Chelyabinsk meteor

The Chelyabinsk meteor was a superbolide that entered Earth's atmosphere over Russia on 15 February 2013 at about 09:20 YEKT (03:20 UTC). It was caused by an approximately near-Earth asteroid with a speed relative to Earth of 19.16 ± 0.15 kilometres per second (60,000–69,000 km/h or 40,000–42,900 mph). It quickly became a brilliant superbolide meteor over the southern Ural region. The light from the meteor was brighter than the Sun, visible up to away. It was observed over a wide area of the region and in neighbouring republics. Some eyewitnesses also felt intense heat from the fireball.
Due to its high velocity and shallow angle of atmospheric entry, the object exploded in an air burst over Chelyabinsk Oblast, at a height of around . The explosion generated a bright flash, producing a hot cloud of dust and gas that penetrated to , and many surviving small fragmentary meteorites, as well as a large shock wave. The bulk of the object's energy was absorbed by the atmosphere, with a total kinetic energy before atmospheric impact estimated from infrasound and seismic measurements to be equivalent to the blast yield of 400–500 kilotons of TNT (about 1.4–1.8 PJ) range – 26 to 33 times as much energy as that released from the atomic bomb detonated at Hiroshima, and the rough equivalent in energy output to the former Soviet Union's own mid-August 1953 initial attempt at a thermonuclear device.
The object was undetected before its atmospheric entry, in part because its radiant (source direction) was close to the Sun. Its explosion created panic among local residents, and about 1,500 people were injured seriously enough to seek medical treatment. All of the injuries were due to indirect effects rather than the meteor itself, mainly from broken glass from windows that were blown in when the shock wave arrived, minutes after the superbolide's flash. Some 7,200 buildings in six cities across the region were damaged by the explosion's shock wave, and authorities scrambled to help repair the structures in sub-freezing temperatures.
With an estimated initial mass of about 12,000–13,000 tonnes (13,000–14,000 short tons), and measuring about in diameter, it is the largest known natural object to have entered Earth's atmosphere since the 1908 Tunguska event, which destroyed a wide, remote, forested, and very sparsely populated area of Siberia. The Chelyabinsk meteor is also the only meteor confirmed to have resulted in many injuries. (Injuries and deaths from the 1490 Ch'ing-yang event are uncertain.) No deaths were reported.
The earlier-predicted and well-publicized close approach of a larger asteroid on the same day, the roughly 367943 Duende, occurred about 16 hours later; the very different orbits of the two objects showed they were unrelated to each other.
Initial reports.
Local residents witnessed extremely bright burning objects in the sky in Chelyabinsk, Kurgan, Sverdlovsk, Tyumen, and Orenburg Oblasts, the Republic of Bashkortostan, and in neighbouring regions in Kazakhstan, when the asteroid entered the Earth's atmosphere over Russia. Amateur videos showed a fireball streaking across the sky and a loud boom several minutes afterwards. Some eyewitnesses claim they felt intense heat from the fireball.
The event began at 09:20:21 Yekaterinburg time, several minutes after sunrise in Chelyabinsk, and minutes before sunrise in Yekaterinburg. According to eyewitnesses, the bolide appeared brighter than the sun, as was later confirmed by NASA. An image of the object was also taken shortly after it entered the atmosphere by the weather satellite Meteosat 9. Witnesses in Chelyabinsk said that the air of the city smelled like "gunpowder", "sulfur" and "burning odors" starting about 1 hour after the fireball and lasting all day.
Atmospheric entry.
The visible phenomenon due to the passage of an asteroid or meteoroid through the atmosphere is called a meteor. If the object reaches the ground, then it is called a meteorite. During the Chelyabinsk meteoroid's traversal, there was a bright object trailing smoke, then an air burst (explosion) that caused a powerful blast wave. The latter was the only cause of the damage to thousands of buildings in Chelyabinsk and its neighbouring towns. The fragments then entered dark flight (without the emission of light) and created a strewn field of numerous meteorites on the snow-covered ground (officially named Chelyabinsk meteorites).
The last time a similar phenomenon was observed in the Chelyabinsk region was the Kunashak meteor shower of 1949, after which scientists recovered about weighing over in total. The Chelyabinsk meteor is thought to be the biggest natural space object to enter Earth's atmosphere since the 1908 Tunguska event, and the only one confirmed to have resulted in many injuries, although a small number of panic-related injuries occurred during the Great Madrid Meteor Event of 10 February 1896.
Preliminary estimates released by the Russian Federal Space Agency indicated the object was an asteroid moving at about in a "low trajectory" when it entered Earth's atmosphere. According to the Russian Academy of Sciences, the meteor then pushed through the atmosphere at a velocity of The radiant (the apparent position of origin of the meteor in the sky) appears from video recordings to have been above and to the left of the rising Sun.
Early analysis of CCTV and dashcam video posted online indicated that the meteor approached from the southeast, and exploded about 40 km south of central Chelyabinsk above Korkino at a height of , with fragments continuing in the direction of Lake Chebarkul. On 1 March 2013 NASA published a detailed synopsis of the event, stating that at peak brightness (at 09:20:33 local time), the meteor was 23.3 km high, located at 54.8°N, 61.1°E. At that time it was travelling at about —almost 60 times the speed of sound. In November 2013, results were published based on a more careful calibration of dashcam videos in the field weeks after the event during a Russian Academy of Sciences field study, which put the point of peak brightness at 29.7 km altitude and the final disruption of the thermal debris cloud at 27.0 km, settling to 26.2 km, all with a possible systematic uncertainty of ±0.7 km.
The United States space agency NASA estimated the diameter of the bolide at about 17–20 m and has revised the mass several times from an initial , until reaching a final estimate of 10,000 tonnes. The air burst's blast wave, when it hit the ground, produced a seismic wave which registered on seismographs at magnitude 2.7.
The Russian Geographical Society said the passing of the meteor over Chelyabinsk caused three blasts of different energy. The first explosion was the most powerful, and was preceded by a bright flash, which lasted about five seconds. Initial newspaper altitude estimates ranged from with an explosive equivalent, according to NASA, of roughly , although there is some debate on this yield (500 kt is exactly the same energy released by the Ivy King nuclear explosion in 1952). According to a paper in 2013, all these ~500 kiloton yield estimates for the meteor airburst are "uncertain by a factor of two because of a lack of calibration data at those high energies and altitudes".
The hypocentre of the explosion was to the south of Chelyabinsk, in Yemanzhelinsk and Yuzhnouralsk. Due to the height of the air burst, the atmosphere absorbed most of the explosion's energy. The explosion's blast wave first reached Chelyabinsk and environs between less than 2 minutes 23 seconds and 2 minutes 57 seconds later. The object did not release all of its kinetic energy in the form of a blast wave as some 90 kilotons of TNT of the total energy of the main airburst's fireball was emitted as visible light according to NASA's Jet Propulsion Laboratory, and two main fragments survived the primary airburst disruption at ; they flared around , with
one falling apart at and the other remaining luminous down to
, with part of the meteoroid continuing on its general trajectory to punch a hole in the frozen Lake Chebarkul, an impact that was fortuitously captured on camera and released in November 2013.
The infrasound waves given off by the explosions were detected by 20 monitoring stations designed to detect nuclear weapons testing run by the Comprehensive Test Ban Treaty Organization (CTBTO) Preparatory Commission, including the distant Antarctic station, some away. The blast of the explosion was large enough to generate infrasound returns, after circling the globe, at distances up to about . Multiple arrivals involving waves that travelled twice around the globe have been identified. The meteor explosion produced the largest infrasounds ever to be recorded by the CTBTO infrasound monitoring system, which began recording in 2001, so great that they reverberated around the world several times, taking over a day to dissipate. Additional scientific analysis of US military infrasound data was aided by an agreement reached with US authorities to allow its use by civilian scientists, implemented only about a month before the Chelyabinsk meteor event.
A preliminary estimate of the explosive energy by astronomer Boris Shustov, director of the Russian Academy of Sciences Institute of Astronomy, was , another using empirical period-yield scaling relations and the infrasound records, by Peter Brown of the University of Western Ontario gave a value of and represents a best estimate for the yield of this airburst; there remains a potential "uncertainty [in the order of] a factor of two in this yield value". Brown and his colleagues also went on to publish a paper in November 2013 which stated that the "widely referenced technique of estimating airburst damage does not reproduce the [Chelyabinsk] observations, and that the mathematical relations found in the book "The Effects of Nuclear Weapons" which are based on the effects of nuclear weapons—[which is] almost always used with this technique—overestimate blast damage [when applied to meteor airbursts]". A similar overestimate of the explosive yield of the Tunguska airburst also exists; as incoming celestial objects have rapid directional motion, the object causes stronger blast wave and thermal radiation pulses at the ground surface than would be predicted by a stationary object exploding, limited to the height at which the blast was initiated-where the object's "momentum is ignored". Thus a meteor airburst of a given energy is "much more damaging than an equivalent [energy] nuclear explosion at the same altitude".
The seismic wave produced when the primary airburst's blast struck the ground yields a rather uncertain "best estimate" of 430 kilotons (momentum ignored), corresponding to the seismic wave which registered on seismographs at magnitude 2.7.
Brown also states that the double smoke plume formation, as seen in photographs, is believed to have coincided near the primary airburst section of the dust trail (as also pictured following the Tagish Lake fireball), and it likely indicates where rising air quickly flowed into the center of the trail, essentially in the same manner as a moving 3D version of a mushroom cloud. Photographs of this smoke trail portion, before it split into two plumes, show this cigar-shaped region glowing incandescently for a few seconds. This region is the area in which the maximum of material ablation occurred, with the double plume persisting for a time and then appearing to rejoin or close up.
Injuries and damage.
The blast created by the meteor's air burst produced extensive ground damage over an irregular elliptical area around a hundred kilometres wide, and a few tens of kilometres long, with the secondary effects of the blast being the main cause of the considerable number of injuries. Russian authorities stated that 1,491 people sought medical attention in Chelyabinsk Oblast within the first few days. Health officials said 112 people had been hospitalised, with two in serious condition. A woman with a broken spine was flown to Moscow for treatment. Most of the injuries were caused by the secondary blast effects of shattered, falling or blown-in glass. The intense light from the meteor, momentarily 30 times brighter than the Sun, also produced injuries, leading to over 180 cases of eye pain, and 70 people subsequently reported temporary flash blindness. Twenty people reported ultraviolet burns similar to sunburn, possibly intensified by the presence of snow on the ground. Vladimir Petrov, when meeting with scientists to assess the damage, reported that he sustained so much sunburn from the meteor that the skin flaked only days later.
A fourth-grade teacher in Chelyabinsk, Yulia Karbysheva, was hailed as a hero after saving 44 children from imploding window glass cuts. Despite not knowing the origin of the intense flash of light, Karbysheva thought it prudent to take precautionary measures by ordering her students to stay away from the room's windows and to perform a duck and cover maneuver and then to leave a building. Karbysheva, who remained standing, was seriously lacerated when the blast arrived and window glass severed a tendon in one of her arms and left thigh; none of her students, whom she ordered to hide under their desks, suffered cuts. The teacher was taken to a hospital which received 112 people that day. The majority of the patients were suffering from cuts.
After the air blast, car alarms went off and mobile phone networks were overloaded with calls. Office buildings in Chelyabinsk were evacuated. Classes for all Chelyabinsk schools were cancelled, mainly due to broken windows. At least 20 children were injured when the windows of a school and kindergarten were blown in at 09:22. Following the event, government officials in Chelyabinsk asked parents to take their children home from schools.
Approximately of a roof at a zinc factory collapsed during the incident. Residents in Chelyabinsk whose windows were smashed quickly sought to cover the openings with anything available, to protect themselves against temperatures of . Approximately 100,000 home-owners were affected, according to Chelyabinsk Oblast Governor Mikhail Yurevich. He also said that preserving the water pipes of the city's district heating was the primary goal of the authorities as they scrambled to contain further post-explosion damage.
By 5 March 2013 the number of damaged buildings was tallied at over 7,200, which included some 6,040 apartment blocks, 293 medical facilities, 718 schools and universities, 100 cultural organizations, and 43 sport facilities, of which only about 1.5% had not yet been repaired. The oblast governor estimated the damage to buildings at more than 1 billion rubles (approximately Chelyabinsk authorities said that broken windows of apartment homes, but not the glazing of enclosed balconies, would be replaced at the state's expense. One of the buildings damaged in the blast was the Traktor Sport Palace, home arena of Traktor Chelyabinsk of the Kontinental Hockey League (KHL). The arena was closed for inspection, affecting various scheduled events, and possibly the postseason of the KHL.
The irregular elliptical disk shape/"spread-eagled butterfly" ground blast damage area, produced by the airburst, is a phenomenon first noticed upon studying the other larger airburst event: Tunguska.
Reactions.
The Chelyabinsk meteor struck without warning. Dmitry Medvedev, the Prime Minister of Russia, confirmed a meteor had struck Russia and said it proved that the "entire planet" is vulnerable to meteors and a spaceguard system is needed to protect the planet from similar objects in the future. Dmitry Rogozin, the deputy prime minister, proposed that there should be an international program that would alert countries to "objects of an extraterrestrial origin", also called potentially hazardous objects.
Colonel General Nikolay Bogdanov, commander of the Central Military District, created task forces that were directed to the probable impact areas to search for fragments of the asteroid and to monitor the situation. Meteorites (fragments) measuring were found from Chebarkul in the Chelyabinsk region.
On the day of the impact, Bloomberg News reported that the United Nations Office for Outer Space Affairs had suggested the investigation of creating an "Action Team on Near-Earth Objects", a proposed global asteroid warning network system, in face of 's approach. As a result of the impact, two scientists in California proposed directed-energy weapon technology development as a possible means to protect Earth from asteroids. Furthermore, the NEOWISE satellite was brought out of hibernation for its second mission extension to scan for near-earth objects. Later in 2013 NASA began annual asteroid impact simulation testing.
Frequency.
It is estimated that the frequency of airbursts from objects 20 metres across is about once in every 60 years. There have been three incidents in the previous century involving a comparable energy yield or higher: the 1908 Tunguska event, the 1930 Curuçá River event, and in 1963 off the coast of Prince Edward Islands in the Indian Ocean. Two of those were over unpopulated areas.
Centuries before, the 1490 Ch'ing-yang event, of an unknown magnitude, apparently caused 10,000 deaths. While modern researchers are skeptical about the 10,000 deaths figure, the 1908 Tunguska event would have been devastating over a highly populous district.
Origin.
Based on its entry direction and speed of 19 kilometres per second, the Chelyabinsk meteor apparently originated in the asteroid belt between Mars and Jupiter. It was probably an asteroid fragment. The meteorite has veins of black material which had experienced high-pressure shock, and were once partly melted due to a previous collision. The metamorphism in the chondrules in the meteorite samples indicates the rock making up the meteor had a history of collisions and was once several kilometres below the surface of a much larger LL chondrite asteroid. The Chelyabinsk asteroid probably entered an orbital resonance with Jupiter (a common way for material to be ejected from the asteroid belt) which increased its orbital eccentricity until its perihelion was reduced enough for it to be able to collide with the Earth.
Meteorites.
In the aftermath of the air burst of the body, many small meteorites fell on areas west of Chelyabinsk, generally at terminal velocity, about the speed of a piece of gravel dropped from a skyscraper. Analysis of the meteor showed that all resulted from the main breakup at 27–34 km altitude. Local residents and schoolchildren located and picked up some of the meteorites, many located in snowdrifts, by following a visible hole that had been left in the outer surface of the snow. Speculators were active in the informal market that emerged for meteorite fragments.
In the hours following the visual meteor sighting, a wide hole was discovered on Lake Chebarkul's frozen surface. It was not immediately clear whether this was the result of an impact; scientists from the Ural Federal University collected 53 samples from around the hole the same day it was discovered. The early specimens recovered were all under in size and initial laboratory analysis confirmed their meteoric origin. They are ordinary chondrite meteorites and contain 10% iron. The fall is officially designated as the Chelyabinsk meteorite. The Chelyabinsk meteor was later determined to come from the LL chondrite group. The meteorites were LL5 chondrites having a shock stage of S4, and had a variable appearance between light and dark types. Petrographic changes during the fall allowed estimates that the body was heated between 65 and 135 degrees during its atmospheric entry.
In June 2013, Russian scientists reported that further investigation by magnetic imaging below the location of the ice hole in Lake Chebarkul had identified a -size meteorite buried in the mud at the bottom of the lake. Before recovery began, the chunk was estimated to weigh roughly .
Following an operation lasting a number of weeks, it was raised from the bottom of the Chebarkul lake on 16 October 2013. With a total mass of , this is the largest found fragment of the Chelyabinsk meteorite. Initially, it tipped and broke the scales used to weigh it, splitting into three pieces.
In November 2013, a video from a security camera was released showing the impact of the fragment at the Chebarkul lake. This is the first recorded impact of a meteorite on video. From the measured time difference between the shadow generating meteor to the moment of impact, scientists calculated that this meteorite hit the ice at about 225 metres per second, 64 percent of the speed of sound.
Media coverage.
The Russian government put out a brief statement within an hour of the event. Serendipitously the news in English was first reported by the hockey site Russian Machine Never Breaks before heavy coverage by the international media and the Associated Press ensued, with the Russian government's confirmation less than two hours afterwards. Less than 15 hours after the meteor impact, videos of the meteor and its aftermath had been viewed millions of times.
The number of injuries caused by the asteroid led the Internet-search giant Google to remove a Google Doodle from their website, created for the predicted pending arrival of another asteroid, . New York City planetarium director Neil deGrasse Tyson stated the Chelyabinsk meteor was unpredicted because no attempt had been made to find and catalogue every near-Earth object. Doing so would be very difficult, and current efforts only aim at a complete inventory of near-Earth objects. The Asteroid Terrestrial-impact Last Alert System, on the other hand, could now predict some Chelyabinsk-like events a day or so in advance, if and only if their radiant is not close to the Sun.
On 27 March 2013, a broadcast episode of the NOVA science television series titled "Meteor Strike" documented the Chelyabinsk meteor, including the significant contribution to meteoritic science made by the numerous videos of the airburst posted online by ordinary citizens. The NOVA program called the video documentation and the related scientific discoveries of the airburst "unprecedented". The documentary also discussed the much greater tragedy "that could have been" had the asteroid entered the Earth's atmosphere more steeply.
Impactor orbital parameters.
Multiple videos of the Chelyabinsk superbolide, particularly from the dashboard cameras and traffic cameras which are ubiquitous in Russia, helped to establish the meteor's provenance as an Apollo asteroid. Sophisticated analysis techniques included the subsequent superposition of nighttime starfield views over recorded daytime images of the same cameras, as well as the plotting of the daytime shadow vectors shown in several online videos.
The radiant of the impacting asteroid was located in the constellation Pegasus in the Northern hemisphere. The radiant was close to the Eastern horizon where the Sun was starting to rise.
The asteroid belonged to the Apollo group of near-Earth asteroids, and was roughly 40 days past perihelion (closest approach to the Sun) and had aphelion (furthest distance from the Sun) in the asteroid belt. Several groups independently derived similar orbits for the object, but with sufficient variance to point to different potential parent bodies of this meteoroid. The Apollo asteroid is one of the candidates proposed for the role of the "parent body" of the Chelyabinsk superbolide. Other published orbits are similar to the 2-kilometre-diameter asteroid to suggest they had once been part of the same object; they may not be able to reproduce the timing of the impact.
Coincidental asteroid approach.
Preliminary calculations rapidly showed that the object was unrelated to the long-predicted close approach of the asteroid 367943 Duende, that flew by Earth 16 hours later at a distance of 27,700 km. The Sodankylä Geophysical Observatory, Russian sources, the European Space Agency, NASA and the Royal Astronomical Society all concluded that the two asteroids had widely different trajectories and therefore could not have been related.


Solar eclipse of July 23, 2036

A partial solar eclipse will occur on Wednesday, July 23, 2036. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. A partial solar eclipse occurs in the polar regions of the Earth when the center of the Moon's shadow misses the Earth.
Images.
Animated path


Michael J. Kurtz

Michael J. Kurtz (born 20 Oct 1947) is an astrophysicist at Harvard University, He has held the title of Astronomer at the Harvard-Smithsonian Center for Astrophysics since 1983, and the additional post of Computer Scientist at the Smithsonian Astrophysical Observatory since 1984. He is especially known both for his research into the distribution of galaxies, and for his creation of the Astrophysics Data System.
Biography.
Kurtz received a BA in Physics from San Francisco State University in 1977 and a Ph.D. from Dartmouth College in 1982. From 1984 to 1992 he was Director of the Image Processing Laboratory.
Publications.
His h-index is 38.
Astronomy.
His most cited papers in astronomy are:
Bibliometrics/Scientometrics.
His most cited publications in bibliometrics/scientometrics are


Solar eclipse of December 7, 2094

A partial solar eclipse will occur on Tuesday, December 7, 2094. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. A partial solar eclipse occurs in the polar regions of the Earth when the center of the Moon's shadow misses the Earth.
It will be visible across North America.


Sednoid

A sednoid is a trans-Neptunian object with a perihelion well beyond the Kuiper cliff at . Only three objects are known from this population: 90377 Sedna, , and 541132 Leleākūhonua (), but it is suspected that there are many more. All three have perihelia greater than . These objects lie outside an apparently nearly empty gap in the Solar System and have no significant interaction with the planets. They are usually grouped with the detached objects. Some astronomers, such as Scott Sheppard, consider the sednoids to be inner Oort cloud objects (OCOs), though the inner Oort cloud, or Hills cloud, was originally predicted to lie beyond 2,000 AU, beyond the aphelia of the three known sednoids.
One attempt at a precise definition of sednoids is any body with a perihelion greater than and a semi-major axis greater than .
However, this definition applies to , , , , , and , which have a perihelion at 50.02 AU and a semi-major axis of about 700 AU but it is thought to not belong to the Sednoids, but to the same dynamical class as , and .
With their high eccentricities (greater than 0.8), sednoids are distinguished from the high-perihelion objects with moderate eccentricities that are in a stable resonance with Neptune, namely , , , and .
Unexplained orbits.
The sednoids' orbits cannot be explained by perturbations from the giant planets, nor by interaction with the galactic tides. If they formed in their current locations, their orbits must originally have been circular; otherwise accretion (the coalescence of smaller bodies into larger ones) would not have been possible because the large relative velocities between planetesimals would have been too disruptive. Their present elliptical orbits can be explained by several hypotheses:
Known members.
The three published sednoids, like all of the more extreme detached objects (objects with semi-major axes > 150 AU and perihelia > 30 AU; the orbit of Neptune), have a similar orientation (argument of perihelion) of ≈ 0° (). This is not due to an observational bias and is unexpected, because interaction with the giant planets should have randomized their arguments of perihelion (ω), with precession periods between 40 Myr and 650 Myr and 1.5 Gyr for Sedna. This suggests that one or more undiscovered massive perturbers may exist in the outer Solar System. A super-Earth at 250 AU would cause these objects to librate around ω = for billions of years. There are multiple possible configurations and a low-albedo super-Earth at that distance would have an apparent magnitude below the current all-sky-survey detection limits. This hypothetical super-Earth has been dubbed Planet Nine. Larger, more-distant perturbers would also be too faint to be detected.
, 27 known objects have a semi-major axis greater than 150 AU, a perihelion beyond Neptune, an argument of perihelion of , and an observation arc of more than 1 year. , , , , , and are near the limit of perihelion of 50 AU, but are not considered sednoids.
On 1 October 2018, Leleākūhonua, then known as , was announced with perihelion of 65 AU and a semimajor axis of 1094 AU. With an aphelion over 2100 AU, it brings the object further out than Sedna.
In late 2015, V774104 was announced at the Division for Planetary Science conference as a further candidate sednoid, but its observation arc was too short to know whether its perihelion was even outside Neptune's influence. The talk about V774104 was probably meant to refer to Leleākūhonua () even though V774104 is the internal designation for non-sednoid .
Sednoids might constitute a proper dynamical class, but they may have a heterogeneous origin; the spectral slope of is very different from that of 90377 Sedna.
Theoretical population.
Each of the proposed mechanisms for Sedna's extreme orbit would leave a distinct mark on the structure and dynamics of any wider population. If a trans-Neptunian planet were responsible, all such objects would share roughly the same perihelion (≈80 AU). If Sedna had been captured from another planetary system that rotated in the same direction as the Solar System, then all of its population would have orbits on relatively low inclinations and have semi-major axes ranging from 100–500 AU. If it rotated in the opposite direction, then two populations would form, one with low and one with high inclinations. The perturbations from passing stars would produce a wide variety of perihelia and inclinations, each dependent on the number and angle of such encounters.
Acquiring a larger sample of such objects would therefore help in determining which scenario is most likely. "I call Sedna a fossil record of the earliest Solar System", said Brown in 2006. "Eventually, when other fossil records are found, Sedna will help tell us how the Sun formed and the number of stars that were close to the Sun when it formed." A 2007–2008 survey by Brown, Rabinowitz and Schwamb attempted to locate another member of Sedna's hypothetical population. Although the survey was sensitive to movement out to 1,000 AU and discovered the likely dwarf planet Gonggong, it detected no new sednoids. Subsequent simulations incorporating the new data suggested about 40 Sedna-sized objects probably exist in this region, with the brightest being about Eris's magnitude (−1.0).
Following the discovery of Leleākūhonua, Sheppard et al. concluded that it implies a population of about 2 million Inner Oort Cloud objects larger than 40 km, with a total mass in the range of (several times the mass of the asteroid belt and 80% the mass of Pluto).


Boris Komitov

Boris Petrov Komitov () (b. April 5, 1954, Stara Zagora, Bulgaria) is a Bulgarian astronomer and geophysicist. He is an active researcher in the fields of physics of planetary and comet atmospheres, solar physics and solar-climate relationships. He has authored more than 70 peer-reviewed science articles, 50 popular-science articles as well as 3 books concerning the physics of the Solar System, the Sun and the Solar-Earth Connections. In 2008 the Minor Planet Centre at the International Astronomical Union named an asteroid from the main asteroid belt (between Mars and Jupiter) after him in recognition of his scientific contributions and educational work (20363 Komitov 1998KU1).


Joseph Baxendell

Joseph Baxendell (1815–1887) was a British meteorologist and astronomer.
Background.
He was the son of Thomas Baxendell and Mary his wife, née Shepley, and was born at Manchester on 19 April 1815. He received his early education at Thomas Whalley's school in Cheetham Hill, Manchester.
He left school at the age of fourteen, but not before his natural love of science had been noticed and fostered by his mother and by his schoolmaster.
He made good use of his powers of observation during six years spent at sea from his fourteenth to his twentieth year. In the Pacific he witnessed the shower of meteors in November 1833. When he abandoned seafaring life in 1835 he returned to Manchester, and for a while assisted his father, who was a land steward.
Career.
Baxendall afterwards had a business of his own as an estate agent. From the time of his return to Manchester he pursued, in a quiet unobtrusive way, his studies in astronomy and meteorology, in the former of which pursuits he had the advantage of the use of the observatory of his friend Robert Worthington at Crumpsall Hall, near Manchester.
His first contribution to the Royal Astronomical Society was made in 1849. He subsequently wrote for the Royal Society's "Proceedings", the Liverpool Astronomical Society's "Journal", and several other publications, but the greater and more important portion of his work was contributed to the Manchester Literary and Philosophical Society, of which he became a member in January 1858. In the following year he became a Member of Council, and in 1861 became joint Secretary as well as Editor of the society's 'Proceedings.' The former post he retained until 1885, and the latter until his death. As colleagues in the secretaryship he had Henry Enfield Roscoe until 1873, and afterwards Osborne Reynolds. He was one of the founders of the physical and mathematical section of the society in 1859.
He was enrolled as a fellow of the Royal Astronomical Society in 1858, but did not become a Fellow of the Royal Society until 1884. In February 1859 he succeeded Henry Halford Jones as astronomer to the Manchester corporation. Some years subsequently he superintended the erection of the Fernley meteorological observatory in Hesketh Park, Southport, and was appointed meteorologist to the corporation of Southport. From 1873 to 1877 he was a member of the Crumpsall local board.
His scientific contributions, of which sixty-seven are enumerated in the Royal Society's "Catalogue of Scientific Papers", have been ably summarised by Dr. J. Bottomley in the paper mentioned below. Of his astronomical observations, perhaps the most important are those embodied in various catalogues of variable stars. His meteorological and terrestrial-magnetical researches were of conspicuous importance, and he was one of the main pioneers in detecting the close connection between those sciences and solar physics.
Among other valuable suggestions for the practical application of meteorology was that for the use of storm signals, concerning which he had a protracted controversy with the board of trade. He predicted the long drought of 1868, and helped enable the Manchester corporation to regulate the supply of water and so mitigate the inconvenience that ensued. On another occasion he predicted the outbreak of an epidemic at Southport.
His later years were passed at Birkdale, near Southport, where he died on 7 October 1887. In religion he was a churchman and a staunch Anglo-Israelite.
Family.
He married, in 1865, Mary Anne, sister of Norman Robert Pogson, the government astronomer for Madras, and left an only son, named after himself, who succeeded him as meteorologist to the corporation of Southport.


Geoffrey Davies (cricketer)

Geoffrey Boisselier Davies (26 October 1892 – 26 September 1915) was an English cricketer.
Davies was educated at Rossall School where he played cricket for the school 1909–12, being captain in 1912. He also played for Essex in 1912. He went up to Selwyn College, Cambridge, and played for both Cambridge University and Essex in 1913 and 1914. In the First World War he was commissioned in the Essex Regiment and held the rank of Captain when he was killed in France in 1915.


Nanda Rea

Nanda Rea is a scientific researcher in the field of astrophysics, currently based in Barcelona, Spain working as a staff scientist for the Consejo Superior de Investigaciones Científicas and Institut d'Estudis Espacials de Catalunya.
Education and career.
Nanda Rea was born in Rome from an iItalo-Argentinian dad and an Iranian mother. She studied Physics at the University of Rome Tor Vergata, and specialised in Astrophysics at the end of her Master studies. In 2004, while pursuing her PhD at the National Italian Institute for Astrophysics (INAF), she moved to The Netherlands with an EU Marie Curie fellowship, aimed at training young students to mobility within Europe. She joined the Netherlands Institute for Space Research (SRON) where she graduated and then continued working until 2007. Thanks to an NWO VENI Fellowship she worked at the University of Amsterdam until 2009, when moved to Spain with a Ramon y Cajal Fellowship. Between 2012 and 2016 she moved back to The Netherlands as a Research Group Leader at the University of Amsterdam with a VIDI NWO Award. Since 2016 she is a staff scientist at the Consejo Superior de Investigaciones Científicas (CSIC), where she has a large group founded by an H2020 European Research Council Consolidator Grant.
Selected publications.
9 *"A low-magnetic field Soft Gamma Repeater" – Rea N., Esposito P., Turolla R. et al. 2010, Science 330, 944 (ESA Press Release, NASA Press Releases)


104P/Kowal

104P/Kowal, also known as Kowal 2, is a periodic Jupiter-family comet discovered by Charles T. Kowal in 1979. The orbit was confirmed after new sightings in 1991 and 1998.
In 2003, Gary Kronk and Brian Marsden noticed that an object observed by Leo Boethin in 1973 was actually 104P/Kowal. From Boethin's report, it was apparent that comet Kowal 2 had been in a short, major outburst to apparent magnitude 9.5 in 1973.


Ott Planetarium

The Ott Planetarium is a planetarium at Weber State University in Ogden, Utah, USA. The facility is named for Layton P. Ott and the Ott family. The planetarium is operated by university students and is a place of learning for audiences and staff alike.
The Facility.
The Ott Planetarium star theater seats 60 persons under a 9.1 meter (30 foot) diameter perforated aluminum dome. Images and video are projected onto the dome with a single projector located in the center of the room. The star theater is equipped with 5.1 channel surround sound.
In December 2004 the Ott Planetarium upgraded its main projection system from a 1969 Spitz A4 to a Konica Minolta Mediaglobe fulldome video system. The Mediaglobe upgrade replaced the star projector and over 30 slide and special effects projectors. Shortly after the Mediaglobe upgrade, planetarium staff began producing original content in the new digital format.
In 2006 the planetarium received a $1 Million U.S. Congressional Earmark to fund the development of educational programs. Part of this grant was used to purchase a 128 CPU render cluster and workstations for star show production.
Star Shows.
The Ott Planetarium offers star shows to the public through its public events program. The planetarium is a popular field trip destination - the star theater can be reserved for classes, groups, family outings, Boy Scouts and Girl Scouts. The Ott Planetarium serves over 20,000 people per year through field trips, public nights, and other public programs.
Original Productions.
The Ott Planetarium produces original fulldome content with a stated commitment to scientific accuracy and educational effectiveness.
Astro Otters and Astro Otters Jr. are module-based astronomy education programs. The population and sequence of these modules can be altered to meet the astronomy curriculum requirements of states or provinces. The Astro Otters program modules were produced with Blender 3D.
Cosmic Journey features images from NASA's Great Observatories, including the Hubble Space Telescope and the Spitzer Space Telescope. The show is narrated by astrophysicist, Dr. Stacy Palen. Cosmic Journey was produced with Blender 3D and uses a 3D adaptation of the Ken Burns Effect.


Margaretha Kirch

Margaretha Kirch (b. ca. 1703, d. after 1744) was a German astronomer.
She was the daughter of the astronomers Gottfried Kirch and Maria Margarethe Kirch and the sister of Christfried Kirch. She and her sister Christine Kirch were educated in astronomy from the age of ten and worked as the assistants of their brother. Kirch did the calculations and assisted in the observations for Christfried Kirch.
Few details are known about her life. She was only seven years old when her father died and never married.
Like her sister Christine, she was taught astronomy at the age of 10 and both initially assisted her brother Christfried with his observations. Margaretha later made observations of the weather and the starry sky, which she recorded in a weather observation diary.
On 3 January 1744 she discovered the Great Comet C / 1743 X1 and, using a 2-foot and a 6-foot telescope, led daily observations and measurements of it in her watch book until 25 February 1744.
After the comet had passed the sun, Margaretha observed and drew a streaky splitting of the comet's tail on March 5, which was only observed on the following four days by well-known astronomers such as Joseph-Nicolas Delisle and Gottfried Heinsius in Saint Petersburg, as well as Jean-Philippe de Chéseaux in Lausanne. In particular, her observation of March 7th is also recorded in an engraving.


Star clock

A star clock (or nocturnal) is a method of using the stars to determine the time. This is accomplished by measuring the Big Dipper's position in the sky based on a standard clock, and then employing simple addition and subtraction. This method requires no tools; others use an astrolabe and a planisphere.
A clock's regulator can be adjusted so that it keeps the Mean Sidereal Time rate. When it is then set to an observer's Local Mean Sidereal Time then a star will transit the meridian (passing directly north or south) at the sidereal time of the star's Right Ascension.


Beddgelert meteorite


Variable star designation

In astronomy, a variable star designation is a unique identifier given to variable stars. It uses a variation on the Bayer designation format, with an identifying label (as described below) preceding the Latin genitive of the name of the constellation in which the star lies. See List of constellations for a list of constellations and the genitive forms of their names. The identifying label can be one or two Latin letters or a "V" plus a number (e.g. V399). Examples are R Coronae Borealis, YZ Ceti, V603 Aquilae.
Naming.
The current naming system is:
The second letter is never nearer the beginning of the alphabet than the first, e.g., no star can be BA, CA, CB, DA and so on.
History.
In the early 19th century few variable stars were known, so it seemed reasonable to use the letters of the Latin script. Because very few constellations contained stars with uppercase Latin-letter Bayer designation greater than Q, the letter R was chosen as a starting point so as to avoid confusion with letter spectral types or the (now rarely used) Latin-letter Bayer designations. Although Lacaille had used uppercase R to Z letters in a few cases, for example X Puppis (HR 2548), these designations were either dropped or accepted as variable star designations. The star T Puppis was accepted by Argelander as a variable star and is included in the General Catalogue of Variable Stars with that designation but is now classed as non-variable.
This variable star naming convention was developed by Friedrich W. Argelander. There is a widespread belief according to which Argelander chose the letter R for German "rot" or French "rouge", both meaning "red", because many variable stars known at that time appear red. However, Argelander's own statement disproves this.
By 1836, even the letter S had only been used in one constellation, Serpens. With the advent of photography the number of variables piled up quickly, and variable star names soon fell into the Bayer trap of reaching the end of the alphabet while still having stars to name. After two subsequent supplementary double-lettering systems hit similar limits, numbers were finally introduced.
As with all categories of astronomical objects, names are assigned by the International Astronomical Union (IAU). The IAU delegates the task to the Sternberg Astronomical Institute in Moscow, Russia. Sternberg publishes the General Catalog of Variable Stars (GCVS), which is periodically (approximately once every two years) amended by the publication of a new "Name-List" of variable stars. For example, in December 2011 the 80th Name-List of Variable Stars, Part II, was released, containing designations for 2,161 recently discovered variable stars; these brought the total number of variable stars in the GCVS to 45,678. Among the newly designated objects were V0654 Aurigae, V1367 Centauri, and BU Coronae Borealis.


Michael H. Hecht

Michael H. Hecht is a research scientist, the associate director for research management at the Massachusetts Institute of Technology's Haystack Observatory, and the former deputy project director of the Event Horizon Telescope. He served as the lead scientist for the Microscopy, Electrochemistry, and Conductivity Analyzer instrument on the Phoenix Mars lander, and as the principal investigator for the Mars Oxygen ISRU Experiment (MOXIE) instrument on the Mars 2020 rover.
Hecht obtained an BA in Physics from Princeton University, an MS from the Massachusetts Institute of Technology, and a Ph.D. from Stanford University in 1982.
Hecht joined the staff of California Institute of Technology's Jet Propulsion Laboratory (JPL) in 1982, where he researched microelectromechanical systems, surface and interface science, scientific instrument development, and planetary science. He co-invented the Ballistic Electron Emission Microscopy system and published several highly-cited papers on metal-semiconductor interfaces, for which he received the newly renamed Lew Allen Award for Excellence in 1990. At JPL, as the supervisor of the Microdevices Laboratory's In-Situ Exploration Technology Group, he developed the concept for the Deep Space 2 micro-landers, which flew to Mars in 1999. He was later named the project manager, co-investigator, and project scientist for the Mars Environmental Compatibility Assessment (MECA) instrument for the cancelled Mars Surveyor 2001 mission. The MECA instrument was later flown as the Microscopy, Electrochemistry, and Conductivity Analyzer on the Phoenix mission to Mars in 2007, with Hecht as lead scientist and co-investigator, and was instrumental in the discovery of perchlorate in Martian soil. Based on that work, Hecht published highly-cited papers on the chemistry of Martian soil and the existence of water on Mars.
After almost 30 years at JPL, Hecht began working for MIT's Haystack Observatory. In 2014, the MOXIE instrument, for which Hecht is the principal investigator, was selected as one of the instruments on the "Perseverance" rover for the Mars 2020 mission. In 2019, Hecht was one of the scientists awarded the 2020 Breakthrough Prize in Fundamental Physics for his work with the Event Horizon Telescope to produce the first image of a supermassive black hole.


Camelopardalis in Chinese astronomy

According to traditional Chinese uranography, the modern constellation Camelopardalis is located in Three Enclosures (三垣, "Sān Yuán")
The name of the western constellation in modern Chinese is 鹿豹座 ("lù bào zuò"), meaning "the leopard-deer constellation".
Stars.
The map of Chinese constellation in constellation Camelopardalis area consists of :


Julius Schiller

Julius Schiller (c. 1580 – 1627) was a lawyer from Augsburg, who like his fellow citizen and colleague Johann Bayer published a star atlas in celestial cartography.
In the year of his death, Schiller, with Bayer's assistance, published the star atlas "Coelum Stellatum Christianum" which replaced the pagan names of constellations with biblical and early Christian figures. Specifically, Schiller replaced the zodiacal constellations with the twelve apostles, the northern constellations by figures from the New Testament and the southern constellations by figures from the Old Testament.
The planets, sun and moon were also replaced by biblical figures.
Lucas Kilian was the artist who engraved the plates.
The star atlas was considered merely a curiosity and, in contrast to Bayer's "Uranometria", did not gain wide acceptance.
"Harmonia Macrocosmica" by Andreas Cellarius (1660) included star maps for Schiller's constellations after the pagan ones.


Near-Earth Asteroid Scout

The Near-Earth Asteroid Scout (NEA Scout) is a planned mission by NASA to develop a controllable low-cost CubeSat solar sail spacecraft capable of encountering near-Earth asteroids (NEA). The NEA Scout will be one of 13 CubeSats to be carried with the Artemis 1 mission into a heliocentric orbit in cis-lunar space on the maiden flight of the Space Launch System (SLS) planned to launch in 2021. The most likely target for the mission is 1991 VG, but this may change based on launch date or other factors. After deployment in cislunar space, NEA Scout will perform a series of lunar flybys to achieve optimum departure trajectory before beginning its two-year-long cruise.
NASA's Marshall Space Flight Center (MSFC) and Jet Propulsion Laboratory (JPL) are jointly developing this mission with support from NASA's Goddard Space Flight Center (GSFC), Lyndon B. Johnson Space Center (JSC), Langley Research Center (LRC), and NASA Headquarters. The principal investigator (science) is Julie Castillo-Rogez from NASA's JPL. The principal investigator (solar sail) is Les Johnson from NASA MSFC.
Overview.
The mission is funded by NASA's Human Exploration and Operations Mission Directorate. Near-Earth asteroids (NEAs) are of interest to science, and as NASA continues to refine its plans to possibly explore these small objects with human explorers, initial reconnaissance with inexpensive robotic precursors is necessary to minimize risks, and inform the required instruments for future reconnaissance missions. The characterization of NEAs that are larger than in diameter is also of great relevance to plan mitigation strategies for planetary defense.
The NEA Scout spacecraft will be one of thirteen CubeSats carried as secondary payload on the maiden flight of the Space Launch System (SLS), a mission called Artemis 1. To measure the physical properties of a near-Earth object, the spacecraft will be performing a slow (10–20 m/s) close () flyby.
Goal.
The NASA Near Earth Asteroid (NEA) Scout mission will demonstrate the capability of an extremely small spacecraft, propelled by a solar sail, to perform reconnaissance of an asteroid at low cost. The goal is to develop a capability that would close knowledge gaps at a near-Earth asteroid in the 1–100 m range. NEAs in the 1–100 m range are poorly characterized due to the challenges that come with detecting, observing, and tracking these for extended periods of time. It has been thought that objects in the 1–100 m size range are fragments of bigger objects. However, it has also been suggested that these objects could actually be rubble-piles.
The mission researchers argue that "characterization of NEAs that are larger than 20 m in diameter is also of great relevance to inform mitigation strategies for planetary defense".
Target.
The planned target, subject to change, is near-Earth object 1991 VG. 1991 VG was discovered shortly before passing just 0.003 AU from Earth on 6 November 1991, and returned within 0.06 AU of Earth in August 2017. It raised interest due to the close approach, and the expectation that such an Earth-similar orbit would not have long term orbital stability. Once the flyby is complete, and if the system is still fully functioning, an extended mission will be contemplated, perhaps leading to the reconnaissance of another asteroid or a re-flyby of 1991 VG several months later.
Payload.
Observations will be achieved using a CubeSat performing a close (~10 km) flyby, equipped with a high resolution science-grade monochromatic camera to measure the physical properties of a near-Earth object. The camera is the ECAM M-50 from Malin Space Science Systems. The measurements to be addressed include target's accurate positioning (position and prediction), rotation rate and pole position, mass, density, mapping of particles and debris field in target vicinity, albedo and asteroid spectral type, surface morphologies and properties, and regolith properties. The mission will use NASA's Deep Space Network as the primary component for communications and tracking.
Design.
The spacecraft architecture, first presented in 2014, is based on a 6-unit CubeSat with a stowed envelope slightly larger than 10 × 20 × 30 cm, a mass of , cold gas thruster system, and primarily based on the use of commercial off-the-shelf parts. While it is possible for a 6U CubeSat to reach an NEA with conventional chemical propulsion, both the number of targets and the launch window would be tightly constrained. By utilizing solar sail propulsion, intercepting a large number of targets in any launch window is made possible. The mission duration is estimated at 2.5 years.
After deployment in cislunar space, NEA Scout will deploy its solar panels and antenna. Following a lunar flyby, the solar sail will deploy and spacecraft checkout will begin. NEA Scout will then perform a series of lunar flybys to achieve optimum departure trajectory before beginning its 2.0 – 2.5 year-long cruise to the asteroid 1991 VG.
Four 6.8 m booms will deploy the single 85 m2 aluminized polyimide solar sail, which is 2.5 μm thick. The sail deployment mechanism is a modification of those of NanoSail and The Planetary Society's LightSail 2 spacecraft. The deployment time for the full sail is approximately 30 minutes.
The avionics module accommodates the printed circuit boards for telecommunications, power distribution unit, command and data handling system, Sun sensors, and a miniaturized star tracker. This module also includes reaction wheels, lithium batteries, and a camera. The solar sail spacecraft attitude control system consists of three actuating subsystems: a reaction wheel control system, a reaction control system, and an adjustable mass translator system.
The cold gas propulsion system is situated below the solar sail and provides detumbling, initial impulsive maneuvers (required for lunar-assisted escape trajectories), and momentum management.
The spacecraft will use the Iris transponder for communications in the X-band.
Photovoltaic solar panels, with rechargeable batteries.


Morris Observatory

Charles S. Morris Observatory is an astronomical observatory owned and operated by Manchester University. Built in 1973, it is located in North Manchester, Indiana.


Nadezhda Aleksandrovna Bobrinskaya

Countess Nadezhda Aleksandrovna Bobrinskaya, née Polovtsova, (May 1865 – 20 March 1920) was an early Russian astronomer and humanitarian volunteer. She published a correction of the orbit of the asteroid 300 Geraldina.
Life.
Her parents were the historian Alexander Polovtsov, who founded the Russian Historical Society, and Nadezha Mikhailovna Polovtsova, who inherited a significant fortune via her adoptive father Alexander von Stieglitz.
In February 1883, she married the statesman and archaeologist Aleksei Aleksandrovich Bobrinsky; it has been suggested that during her marriage she and her husband encouraged the Grand Duke Nicholas Mikhailovich to conspire against the Empress, but the evidence is circumstantial.
At some point, she was an employee of the Pulkovo Observatory, where she made her observations of the asteroid 300 Geraldina. She also made observations of the asteroid 147 Protogeneia.
By 1906, she was divorced.
During the Russo-Japanese War, she worked for the Russian Red Cross in an unknown capacity. She continued charitable work throughout World War I, and died in March 1920 of typhoid fever, contracted during the evacuation of the Ural Army.


Karl Schwarzschild

Karl Schwarzschild (; 9 October 1873 – 11 May 1916) was a German physicist and astronomer.
Schwarzschild provided the first exact solution to the Einstein field equations of general relativity, for the limited case of a single spherical non-rotating mass, which he accomplished in 1915, the same year that Einstein first introduced general relativity. The Schwarzschild solution, which makes use of Schwarzschild coordinates and the Schwarzschild metric, leads to a derivation of the Schwarzschild radius, which is the size of the event horizon of a non-rotating black hole.
Schwarzschild accomplished this while serving in the German army during World War I. He died the following year from the autoimmune disease pemphigus, which he developed while at the Russian front. Various forms of the disease particularly affect people of Ashkenazi Jewish origin.
Asteroid 837 Schwarzschilda is named in his honour, as is the large crater "Schwarzschild", on the far side of the Moon.
Life.
Karl Schwarzschild was born on the 9th of October 1873 in Frankfurt on Main to Jewish parents. His father was active in the business community of the city, and the family had ancestors in the city dating back to the sixteenth century. The family owned two fabric stores in Frankfurt. One of his brothers is the painter Alfred Schwarzschild.  Karl attended a Jewish primary school until 11 years of age and then the Lessing-Gymnasium (as in secondary school). He received an all-encompassing education, including subjects like Latin, Ancient Greek, music and art, but developed a special interest in astronomy early on. In fact he was something of a child prodigy, having two papers on binary orbits (celestial mechanics) published before he was sixteen.
After Graduation in 1890 he attended the University of Strasbourg to study astrology.After 2 years he transferred to the Ludwig Maximilian University of Munich where he obtained his doctorate in 1896 for a work on Henri Poincaré's theories.
From 1897, he worked as assistant at the Kuffner Observatory in Vienna. His work here was dedicated towards photometry of star clusters and laid the foundations for a formula linking the intensity of the star light, exposure time, and the resulting contrast on a photographic plate. An integral part of that theory is the Schwarzschild exponent (astrophotography). In 1899 he returned to Munich to complete his Habilitation.
From 1901 until 1909 he was a professor at the prestigious institute at Göttingen, where he had the opportunity to work with some significant figures, including David Hilbert and Hermann Minkowski. Schwarzschild became the director of the observatory in Göttingen. He married Else Rosenbach, a great granddaughter of Friedrich Wöhler and daughter of a professor of surgery at Göttingen, in 1909. Later that year they moved to Potsdam, where he took up the post of director of the Astrophysical Observatory. This was then the most prestigious post available for an astronomer in Germany.
From 1912, Schwarzschild was a member of the Prussian Academy of Sciences.
At the outbreak of World War I in 1914 he joined the German army, despite being over 40 years old. Yet he volunteered for service. He served on both the western and eastern fronts specifically helping with ballistic calculations.Thereby he rose to the rank of lieutenant in the artillery.
While serving on the front in Russia in 1915, he began to suffer from a rare and painful autoimmune skin disease called pemphigus. Nevertheless, he managed to write three outstanding papers, two on the theory of relativity and one on quantum theory. His papers on relativity produced the first exact solutions to the Einstein field equations, and a minor modification of these results gives the well-known solution that now bears his name — the Schwarzschild metric.
In March 1916 Schwarzschild was cleared from service due to his sickness and returned to Göttingen. Two months later, on May 11, 1916, Schwarzschild's struggle with pemphigus probably eventually led to his death at the age of 42.
He rests in his family grave at the Stadtfriedhof Göttingen.
With his wife Else he had three children: Agathe Thornton (1910-2006) who emigrated to Great Britain in 1933. In 1946 she moved New Zealand where she became a Classics professor at the University of Otago in Dunedin; Martin who went on to become a professor of astronomy at Princeton University; and Alfred (1914-1944) who took his own life due to the persecution of Jews in the Holocaust.
Work.
Thousands of dissertations, articles, and books have since been devoted to the study of Schwarzschild's solutions to the Einstein field equations. However, although Schwarzschild's best known work lies in the area of general relativity, his research interests were extremely broad, including work in celestial mechanics, observational stellar photometry, quantum mechanics, instrumental astronomy, stellar structure, stellar statistics, Halley's comet, and spectroscopy.
Some of his particular achievements include measurements of variable stars, using photography, and the improvement of optical systems, through the perturbative investigation of geometrical aberrations.
Physics of photography.
While at Vienna in 1897, Schwarzschild developed a formula, now known as the Schwarzschild law, to calculate the optical density of photographic material. It involved an exponent now known as the Schwarzschild exponent, which is the formula_1 in the formula:
formula_2
(where formula_3 is optical density of exposed photographic emulsion, a function of formula_4, the intensity of the source being observed, and formula_5, the exposure time, with formula_1 a constant). This formula was important for enabling more accurate photographic measurements of the intensities of faint astronomical sources.
Electrodynamics.
According to Wolfgang Pauli (Theory of relativity), Schwarzschild is the first to introduce the correct Lagrangian formalism of the electromagnetic field as
formula_7
where formula_8 are the electric and magnetic field, formula_9 is the vector potential and formula_10 is the electric potential.
He also introduced a field free variational formulation of electrodynamics (also known as "action at distance" or "direct interparticle action") based only on the world line of particles as
formula_11
where formula_12 are the world lines of the particle, formula_13 the (vectorial) arc element along the world line. Two points on two world lines contribute to the Lagrangian (are coupled) only if they are a zero Minkowskian distance (connected by a light ray), hence the term formula_14. The idea was further developed by Tetrode
and Fokker in the 1920s and Wheeler and Feynman in the 1940s and constitutes an alternative/equivalent formulation of electrodynamics.
Relativity.
Einstein himself was pleasantly surprised to learn that the field equations admitted exact solutions, because of their "prima facie" complexity, and because he himself had only produced an approximate solution. Einstein's approximate solution was given in his famous 1915 article on the advance of the perihelion of Mercury. There, Einstein used rectangular coordinates to approximate the gravitational field around a spherically symmetric, non-rotating, non-charged mass. Schwarzschild, in contrast, chose a more elegant "polar-like" coordinate system and was able to produce an exact solution which he first set down in a letter to Einstein of 22 December 1915, written while Schwarzschild was serving in the war stationed on the Russian front. Schwarzschild concluded the letter by writing: "As you see, the war treated me kindly enough, in spite of the heavy gunfire, to allow me to get away from it all and take this walk in the land of your ideas." In 1916, Einstein wrote to Schwarzschild on this result:
Schwarzschild's second paper, which gives what is now known as the "Inner Schwarzschild solution" (in German: "innere Schwarzschild-Lösung"), is valid within a sphere of homogeneous and isotropic distributed molecules within a shell of radius r=R. It is applicable to solids; incompressible fluids; the sun and stars viewed as a quasi-isotropic heated gas; and any homogeneous and isotropic distributed gas.
Schwarzschild's first (spherically symmetric) solution "does not" contain a coordinate singularity on a surface that is now named after him. In Schwarzschild coordinates, this singularity lies on the sphere of points at a particular radius, called the Schwarzschild radius:
where "G" is the gravitational constant, "M" is the mass of the central body, and "c" is the speed of light in a vacuum. In cases where the radius of the central body is less than the Schwarzschild radius, formula_16 represents the radius within which all massive bodies, and even photons, must inevitably fall into the central body (ignoring quantum tunnelling effects near the boundary). When the mass density of this central body exceeds a particular limit, it triggers a gravitational collapse which, if it occurs with spherical symmetry, produces what is known as a Schwarzschild black hole. This occurs, for example, when the mass of a neutron star exceeds the Tolman–Oppenheimer–Volkoff limit (about three solar masses).
Cultural references.
Karl Schwarzschild appears as a character in the science fiction short story "Schwarzschild Radius" (1987) by Connie Willis.
Schwarzschild's Cat is a comic on XKCD.com comparing the size and cuteness of cats.
Works.
The scientific estate of Karl Schwarzschild is stored in a special collection of the Lower Saxony National- and University Library of Göttingen.


Kristen Sellgren

Kristen Sellgren is a retired American astronomer and Professor Emerita at the College of Natural and Mathematical Sciences, Ohio State University. She won the Newton Lacy Pierce Prize in Astronomy in 1990. She is the founder of SGMA: the AAS committee for orientation & gender minorities in astronomy.
Education and career.
Sellgren graduated from the University of California, San Diego in 1976 with a BA in physics. She obtained a PhD in physics from the California Institute of Technology in 1983 under the advisement of B.T. Soifer and G. Neugebauer. Her graduate thesis was entitled "Near Infrared Studies of Reflection Nebulae." Her areas of expertise include the galactic center of the Milky Way, interstellar dust, and infrared astronomy generally.
After graduating with her bachelor's degree, Sellgren completed a summer research fellowship at Arecibo Observatory in Puerto Rico. After receiving her doctorate, she took a postdoctoral research position at the Space Telescope Science Institute in Baltimore, Maryland. In 1984, Sellgren joined the Institute for Astronomy at the University of Hawaii first as assistant astronomer, and then in 1989, as associate astronomer.
Since 1990, Sellgren has held several appointments at Ohio State University beginning with assistant professor. She was later named associate professor in 1994, and then reached full professorship in 2000 before entering into emerita status in 2011. Also in the year 2000, Sellgren served briefly as visiting professor at the University of Texas at Austin.
Honors and recognition.
In 1973, Sellgren won recognition as a National Merit Scholar. In the same year, she was bestowed the UC Regents Fellowship at the University of California, San Diego. She was awarded the Newton Lacy Pierce Prize in 1990 and later served as Alfred P. Sloan Research Fellow from 1991 to 1993. She was also a AAAS Fellow in 2011. Sellgren is a current member of the American Astronomical Society as well as the International Astronomical Union.


Linda Spilker

Linda Spilker is an American planetary scientist who served as the project scientist for the Cassini mission exploring the planet Saturn. Her research interests include the evolution and dynamics of Saturn's rings.
Career.
Spilker received a B.A.in Physics from California State University, Fullerton in 1977 and an M.S. in Physics from California State University, Los Angeles in 1983. She obtained a Ph.D. in Geophysics and Space Physics from UCLA in 1992. She joined the Jet Propulsion Laboratory in 1977, initially working on the Voyager missions that were launched the same year. She became a Cassini mission scientist in 1990. In 1997, she was the editor of a NASA publication that summarizes the mission's legacy. In 2010 she became the Cassini mission project scientist, a role in which she directed the entire team's scientific investigations. She has appeared as herself in multiple television documentary programs, including several in the PBS Nova series.


Gemini Observatory

The Gemini Observatory is an astronomical observatory consisting of two 8.1-metre (26.6 ft) telescopes, Gemini North and Gemini South, which are located at two separate sites in Hawaii and Chile, respectively. The twin Gemini telescopes provide almost complete coverage of both the northern and southern skies. They are currently among the largest and most advanced optical/infrared telescopes available to astronomers. "(See List of largest optical reflecting telescopes)".
The National Science Foundation (NSF) of the United States, the National Research Council of Canada, CONICYT of Chile, MCTI of Brazil, and MCTIP of Argentina own and operate the Gemini Observatory. The NSF is currently (2017) the majority partner, contributing approximately 70% of the funding needed to operate and maintain both telescopes. The operations and maintenance of the observatory is managed by the Association of Universities for Research in Astronomy (AURA), through a cooperative agreement with NSF. NSF acts as the Executive Agency on behalf of the international partners.
The Gemini telescopes house a suite of modern instruments, offer superb performance in the optical and near-infrared, and employ sophisticated adaptive optics technology to compensate for the blurring effects of the Earth's atmosphere. Gemini is a world-leader in wide-field adaptive optics assisted infrared imaging, and has recently commissioned the Gemini Planet Imager, an instrument that allows researchers to directly image and analyze exoplanets that are a millionth as bright as the host star around which they orbit. Gemini continues to support research in almost all areas of modern astronomy, including the Solar System, exoplanets, star formation and evolution, the structure and dynamics of galaxies, supermassive black holes, distant quasars, and the structure of the Universe on the largest scales.
Past participants in the Gemini Observatory include Australia and the United Kingdom. The UK dropped out of the partnership at the end of 2012 and the Gemini Observatory has responded to the loss of funding by significantly reducing its operating costs, streamlining its operations, and implementing energy savings measures at each site. Both telescopes are also now operated remotely from Base Facility Operations centers in Hilo, Hawaii, and La Serena, Chile.
Overview.
The Gemini Observatory's international Headquarters and Northern Operations Center is located in Hilo, Hawaii at the University of Hawaii at Hilo University Park. The Southern Operations Center is located on the Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile.
Together, the two telescopes cover almost all of the sky except for two areas near the celestial poles: Gemini North cannot point north of declination +89 degrees, and Gemini South cannot point south of declination −89 degrees.
Both Gemini telescopes employ a range of technologies to provide world-leading performance in optical and near-infrared astronomy, including laser guide stars, adaptive optics, multi conjugate adaptive optics, and multi-object spectroscopy. In addition, very high-quality infrared observations are possible due to the advanced protected silver coating applied to each telescope's mirrors, the small secondary mirrors in use (resulting in an f16 focal ratio), and the advanced ventilation systems installed at each site.
History.
It is estimated that the two telescopes cost approximately US$187 million to construct, and a night on each Gemini telescope is worth tens of thousands of U.S. dollars.
The two 8-meter mirror blanks, each weighing over , were fabricated from Corning's Ultra Low Expansion glass. Each blank was constructed by the fusing together of and subsequent sagging of a series of smaller hexagonal pieces. This work was performed at Corning's Canton Plant facility located in upstate New York. The blanks were then transported via ship to REOSC, located south of Paris for final grinding and polishing.
One decision made during design to save money was eliminating the two Nasmyth platforms. This makes instruments like high resolution spectrographs and adaptive optics systems much more difficult to construct, due to the size and mass requirement inherent with Cassegrain instruments. A further challenge in designing large instruments is the requirement to have a specific mass and center-of-mass position to maintain the overall balance of the telescope.
UK funding crisis.
In November 2007 it was announced that the UK's Science and Technology Facilities Council (STFC) had proposed that, to save £4 million annually, it would aim to leave the telescope's operating consortium. At a consortium meeting in January 2008, the conclusion was made that the UK would officially withdraw from the Gemini Partnership and the Gemini Observatory Agreement effective February 28, 2007. This decision significantly disrupted observatory budgets, and resulted in the cancellation of at least one instrument in development at that time, the Precision Radial Velocity Spectrograph.
Since the reason for the UK breaking its part of the agreement seemed to be entirely financial, there was public outcry, including the "Save Astronomy" movement which asked citizens to speak up against the astronomy budget cuts. The UK rethought their decision to withdraw from Gemini, and requested reinstatement into the agreement, and were officially welcomed back on February 27, 2008. However, in December 2009 it was announced that the UK would indeed leave the Gemini partnership in 2012, as well as terminating several other international science partnerships, due to continuing funding limitations.
Directorship.
The first director of Gemini was Matt Mountain, who after holding the post for eleven years left in September 2005 to become director of Space Telescope Science Institute (STScI). He was succeeded by Jean-René Roy, who served for nine months, after which time Doug Simons held the directorship from June 2006 to May 2011. He in turn was succeeded by an interim appointment of the then-retired Fred Chaffee, former director of W. M. Keck Observatory. Chaffee was succeeded in August 2012 by Markus Kissler-Patig, who held the post until June 2017. Dr. Laura Ferrarese succeeded Dr. Kissler-Patig in July 2017 with an interim appointment. The current director is Dr. Jennifer Lotz since September 6, 2018.
Governance and oversight.
The Observatory is governed by the Gemini Board, as defined by the Gemini International Agreement. The Board sets budgetary policy bounds for the Observatory and carries out broad oversight functions, with advice from a Science and Technology Advisory sub-Committee (the STAC) and a Finance sub-Committee. The U.S. holds six of the 13 voting seats on the Gemini Board. The U.S. members of the Board typically serve three year terms and are recruited and nominated by the National Science Foundation (NSF), which represents the US community in all aspects of Gemini operations and development. Gemini is currently managed by the Association of Universities for Research in Astronomy (AURA), Inc., on behalf of the partnership through an award from NSF. AURA has operated Gemini since its construction in the 1990s.
NSF serves as the Executive Agency and acts on behalf of the international participants. NSF has one seat on the Gemini Board; an additional NSF staff member serves as the Executive Secretary to the board. Programmatic management is the responsibility of an NSF Program Officer. The Program Officer monitors operations and development activities at the Observatory, nominates U.S. scientists to Gemini advisory committees, conducts reviews on behalf of the partnership, and approves funding actions, reports, and contracts.
Instrumentation.
Adaptive optics.
Both Gemini telescopes employ sophisticated state-of-the-art adaptive optics systems. Gemini-N routinely uses the ALTAIR system, built in Canada, which achieves a 30–45% Strehl ratio on a 22.5-arcsecond-square field and can feed NIRI, NIFS or GNIRS; it can use natural or laser guide stars. In conjunction with NIRI it was responsible for the discovery of HR8799b.
At Gemini-S the Gemini Multi-Conjugate Adaptive Optics System (GeMS) may be used with the FLAMINGOS-2 near-infrared imager and spectrometry, or the Gemini South Adaptive Optics Imager (GSAOI), which provides uniform, diffraction-limited image quality to arcminute-scale fields of view. GeMS achieved first light on December 16, 2011. Using a constellation of five laser guide stars, it achieved FWHM of 0.08 arc-seconds in H band over a field of 87 arc-seconds square.
An adaptive secondary mirror has been considered for Gemini, which would provide reasonable adaptive-optics corrections (equivalent to natural seeing at the 20th-percentile level for 80% of the time) to all instruments on the telescope to which it is attached. However, , there are no plans to implement such an upgrade to either telescope.
Instruments.
In recent years the Gemini Board has directed the observatory to support only four instruments at each telescope. Because Gemini-N and Gemini-S are essentially identical, the observatory is able to move instruments between the two sites, and does so on a regular basis. Two of the most popular instruments are the Gemini Multi-Object Spectrographs (GMOS) on each of the telescopes. Built in Edinburgh, Scotland by the UK Astronomy Technology Centre, these instruments provide multi-object spectroscopy, long-slit spectroscopy, imaging, and integral field spectroscopy at optical wavelengths. The detectors in each instrument have recently been upgraded with Hamamatsu Photonics devices, which significantly improve performance in the far red part of the optical spectrum (700–1,000 nm).
Near-infrared imaging and spectroscopy are provided by the NIRI, NIFS, GNIRS, FLAMINGOS-2, and GSAOI instruments. The availability and detailed descriptions of these instruments is documented on the Gemini Observatory Web site.
One of the most exciting new instruments at Gemini is GPI, the Gemini Planet Imager. GPI was built by a consortium of US and Canadian institutions to fulfill the requirements of the ExAOC Extreme Adaptive Optics Coronagraph proposal. GPI is an extreme adaptive-optics imaging polarimeter/integral-field spectrometer, which provides diffraction-limited data between 0.9 and 2.4 microns. GPI is able to directly image planets around nearby stars that are one-millionth as bright as their host star.
Gemini also supports a vigorous visitor instrument program. Instruments may be brought to either telescope for short periods of time and used for specific observing programs by the instrument teams. In return for access to Gemini, the instruments are then made available to the entire Gemini community, so that they may be used for other science projects. Instruments that have made use of this program include the Differential Speckle Survey Instrument (DSSI), the Phoenix near-infrared echelle spectrometer, and the TEXES mid-infrared spectrometer. The ESPaDOnS spectrograph situated in the basement of the Canada–France–Hawaii Telescope (CFHT) is also being used as a "visitor instrument", even though it never moves from CFHT. The instrument is connected to Gemini-North via a 270 meter long optic fibre. Known as GRACES, this arrangement provides very high resolution optical spectroscopy on an 8-meter class telescope.
Gemini's silver coating and infrared optimization allow sensitive observations in the mid-infrared part of the spectrum (5–27 µm). Historically, mid-infrared observations have been obtained using T-ReCS at Gemini South and Michelle at Gemini North. Both instruments have imaging and spectroscopic capabilities, though neither is currently being used at Gemini.
Instrumentation development issues.
The first phase of Gemini instrumentation development did not run smoothly; schedules slipped by several years, and budgets sometimes overran by as much as a factor of two. In 2003 the instrument-development process was re-analysed in the Aspen report; for example, an incentive program was introduced where instrument developers were guaranteed substantial allocations of telescope time if they delivered the instrument on time and lose it as the instrument is delayed.
A wide-field multi-object spectrograph achieved substantial scientific support, but would have required major changes to the design of the telescope – effectively it would have required one of the telescopes to be devoted to that instrument. The project was terminated in 2009.
Second-round instrumentation development.
In January 2012, the Gemini Observatory started a new round of instrumentation development. This process has since resulted in the development of a high-resolution optical spectrograph known as GHOST, to be commissioned in 2018. More recently, the Gemini Instrument Feasibility Studies (GIFS) process has led to a solicitation for a medium-resolution, wide-band (350 nm to 2.5 µm in a single exposure) spectrograph. Proposals have been received and a contract is expected to be placed in early 2017, with development to begin shortly thereafter.
Observing and community support.
The Gemini Observatory's primary mission is to serve the general astronomical communities in all of the participant countries; indeed, the Observatory provides the bulk of general access to large optical/infrared telescopes for many of the participants, and represents the only public-access 8 meter class facility in the U.S. The observatory reaches out to its community through National Gemini Offices (NGOs), the U.S. office being located in Tucson at the National Optical Astronomy Observatory. The NGOs provide general support to the users, from proposal preparation through data acquisition, reduction, and analysis.
In any given year the two telescopes typically provided data for over 400 discrete science projects, over two-thirds of which are led by U.S. astronomers. About 50-70 percent of the top-ranked "Band 1" proposals reach 100 percent completion in any given year. Of order 90 percent of the available (clear weather) time is used for science, the rest being allocated to scheduled maintenance or lost to unforeseen technical faults.
Gemini has in recent years developed innovative new observing modes. These include the ‘Large and Long’ program to support requests for large amounts of telescope time and the ‘Fast Turnaround’ program to provide quick access to the telescope. These and other modes have been approved by the Gemini Board of Directors and are proving popular with the user community. In 2015 up to 20 percent of available telescope time was used for Large and Long programs, which in terms of hours of observing attracted five times more user demand than could be accommodated. In the same period approximately 10 percent of telescope time was assigned to the Fast Turnaround program, which in the second half of 2015 was over-subscribed by a factor of 1.6. In 2015 the remaining U.S. time allocation on Gemini was over-subscribed by a factor of approximately 2, consistent with recent years.
Prospects (2017 onwards).
In 2010, the U.S. National Research Council (NRC) conducted its sixth decadal survey in astronomy and astrophysics to recommend key science questions and new initiatives for the current decade. Since both the NRC recommendations and current programs could not be accommodated within subsequent budget projections, the National Science Foundation's Division of Astronomical Sciences, through the Advisory Committee of the Directorate for Mathematical and Physical Sciences (MPS), conducted a community-based portfolio review to make implementation recommendations that would best respond to the decadal survey science questions. The resulting report, Advancing Astronomy in the Coming Decade: Opportunities and Challenges, was released in August 2012 and included recommendations related to all of the major telescope facilities funded by NSF. The Portfolio Review Committee report ranked Gemini Observatory as a critical component of the U.S.'s future astronomical research resources and recommended that the U.S. retain a majority share in the international partnership for at least the next several years. However, given the constraints that were considered, the Committee recommended that the U.S. contribution to Gemini operations be capped in 2017 and beyond.
NSF has since commissioned a National Research Council study, titled "A Strategy to Optimize the U.S. Optical/Infrared System in the Era of the Large Synoptic Survey Telescope". The report made a recommendation that NSF work with its partners in Gemini to ensure that Gemini-South is well positioned for faint-object spectroscopy early in the era of the Large Synoptic Survey Telescope (LSST). Observatory support for the development of a next-generation medium-resolution spectrograph over the next 5–6 years addresses this recommendation directly.
With the signing of the new International Agreement in late 2015, support from the five signatories (the U.S., Canada, Argentina, Brazil, and Chile) is secured for the period 2016-2021. There is also a strong possibility that current limited-term partners, Australia and Korea, will continue their relationship with the observatory in this manner, or will seek to transition to being full participants before the end of the current agreement.
Observations and Research.
The Gemini was one of the telescopes that observed the turn-on of a nuclear transient, along with the Swift space telescope (aka Neil Gehrels "Swift" Observatory since 2018) and the Hiltner telescope (MDM observatory). The transient event was called PS1-13cbe and was located in the Galaxy SDSS J222153.87+003054.2


Caroline Furness

Caroline Ellen Furness (June 24, 1869 – February 9, 1936) was an American astronomer who taught at Vassar College in the early twentieth century. She studied under Mary Watson Whitney at Vassar and was the first woman to earn a PhD in astronomy from Columbia.
Furness was born on 24 June 1869 in Cleveland, Ohio. Her father was a high school science teacher and encouraged her early interest in science. She graduated from Vassar in 1887 and followed in her fathers footsteps becoming a high school science teacher, her true interest was in research though and after three years she returned to Vassar as a research assistant for Mary Watson Whitney. Under Whitney she took part in a nearly decade long program of comet and planet observations. In 1896 she began working at Columbia University under Harold Jacoby and would publish her Ph.D. dissertation "Catalogue of stars within one degree of the North pole and optical distortion of the Helsingfors astro-photographic telescope deduced from photographic measures" there in 1900. In 1903 she returned to Vassar as an instructor.
She collaborated on variable star observations with Whitney from 1909 to 1911. In 1915, she authored the authoritative textbook "Introduction to the Study of Variable Stars".
She became a fellow of the Royal Astronomical Society in 1922.
She died on 9 February 1936 in New York City.
She was an advocate for women's education, particularly in other countries; she wrote a number of articles about the situation of women's higher education in Japan; she was an important member of the local branch of the National Alliance of Unitarian Women.


Patricia Whitelock

Professor Patricia Ann Whitelock (born 22 February 1951) is a British-born astrophysicist with dual British-South African nationality. She is a Fellow of the Royal Society of South Africa (of which she was Vice-President in 2002); a member of the Academy of Science of South Africa; and a member of the South African Institute of Physics (SAIP), (of which she was President in 2001-2003).
She was acting director of the South African Astronomical Observatory from June 2002 to November 2003 and was the director in 2012. Her research is focused on our understanding of the late stages of stellar evolution and mass-loss of evolved stars, the structure of the Milky Way galaxy, and the stellar content of the local group galaxies. Whitelock has been published in 148 peer-reviewed scholarly articles with 36 being as first author, which has been cited in 2883 other publications.
She has been influential in maintaining the position of South Africa as a centre of astronomical excellence. She helped to establish the National Astrophysics and Space Science Program where she served as the first chair of its steering committee between 2002 and 2013. She was also one of the key drivers behind the successful bid by South Africa to host the International Office of Astronomy for Development of the IAU. An important part of her activity has been raising the profile of astronomy amongst the wider African education community. In 2018, she was awarded the De Beers Gold Medal by the SAIP, for "her outstanding research career in astronomy and astrophysics, and for her distinguished and extensive contributions to leadership, education and human capacity development of the Physics and Astronomy community"
Education and early life.
Patricia Whitelock was born in Tynemouth, UK, to Marie (née Galloway) and Philip Whitelock.
Fascinated by the night skies even as a child, she was encouraged to pursue a career in Astronomy in a correspondence with famous British populariser of astronomy Patrick Moore. She attended Sherrardswood School where her aptitude for the quantitative sciences was spotted and nurtured by her physics teacher, Tony Rook. After gaining a 1st Class degree in Astronomy from University College, London in 1972, she completed a PhD, "Ground-based infrared photometry of some astronomical sources", at Imperial College,London in 1976.
After her marriage in 1977 to fellow astronomer John Menzies, they moved to Cape Town to take up posts together at the SAAO, where they continue to work.


Roper Mountain Science Center

Roper Mountain Science Center is located in Greenville, South Carolina. It encompasses a campus containing facilities for studying life and natural sciences, space and physical sciences. Among its facilities are the Living History Farm, the Darrell W. Harrison Hall of Natural Sciences, the Simms Hall of Science, the T.C. Hooper Planetarium, and the Daniel Observatory. The center is a part of the Greenville County School District.
History.
Roper Mountain Science Center was started as a unique partnership between public and private resources. Initial planning for the center began in 1982 and the center opened in 1985.
Charles E. Daniel Observatory.
The principal telescope at the observatory is a refracting telescope. the objective lens was made by Alvan Clark and Sons. The telescope, which was finished in 1882, was installed at the Halsted Observatory of Princeton University. The telescope was rebuilt in 1933 by J. W. Fecker Company. The telescope was transferred to the US Naval Observatory in 1964. In 1968, it was offered to the Greenville County School District. The telescope was renovated and an observatory was built through a donation from the Charles E. Daniel Family Foundation. It is the eighth largest refractor telescope in the United States.


Ingram Planetarium

Ingram Planetarium is a planetarium located at Sunset Beach in Brunswick County, North Carolina. The Board of Trustees of the Ocean Isle Museum Foundation, Inc. is the governing body of Ingram Planetarium as well as the Museum of Coastal Carolina, located at Ocean Isle Beach, North Carolina.


Johann Hommel

Johann Hommel (also "Johannes Homelius", "Hummelius", "Homilius", "Hummel"; 2 February 1518, Memmingen – 4 July 1562, Leipzig) was a German astronomer and mathematician.
Work.
Hommel was appointed professor of mathematics at the University of Leipzig in 1551.
In 1552 or 1553, Richard Cantzlar introduced transversal dot lines in graduations. It was a variant of the zigzag line system introduced by Hommel. Tycho Brahe obtained the zigzag line system from Hommel.
The lunar crater Hommel is named after him.


Exeter Cathedral astronomical clock

The Exeter Cathedral Astronomical Clock is a fifteenth-century astronomical clock in Exeter Cathedral, England. It displays the hour of the day, the day of the lunar month and the phase of the moon. The modern clock mechanism was installed in 1885 by Gillett & Bland of Croydon, and restored in 1910.
History and description.
The clock is thought to date from around 1484.
The outermost numbered circle of the main dial is decorated with a fleur-de-lis which represents the sun, and which orbits the dial once every 24 hours. This indicates the hour of the day, counted from I to XII in Roman numerals in first the right and then the left hemispheres of the clockface. This is an example of a 24-hour analog dial. The tail of the sun's fleur-de-lis points to the day in the lunar month on the inner numbered ring. The half-black, half-silver moon inside the lunar month ring rotates on its axis to show the correct phase of the moon. The earth is represented as a fixed golden ball in the centre of the dial. The Latin inscription "Pereunt et imputantur" below the main dial may be translated as "The hours pass and are reckoned to our account".
A small bell located behind the clock dial chimes the quarter-hours. On the hour, this is followed by the striking of the Peter Bell in the tower above.
In 1759 the smaller upper dial was added, with a single hand to indicate the minutes.
The clock-room is behind the dial on the north wall of the transept, and still houses the clock mechanism. Access is via a doorway visible in the stone wall directly beneath the clock. Legend suggests that the round hole cut in the bottom of the door was for the cathedral cat to gain entry to keep the clock clear of mice and rats. The modern clock mechanism was installed in 1885 by Gillett & Bland of Croydon.
The clock was restored in 1910 by John James Hall FRAS.
The clock is reputed to be the source of the nursery rhyme Hickory Dickory Dock, probably inspired by the round hole in the door described above.


Sarah Frances Whiting

Sarah Frances Whiting (August 23, 1847 – September 12, 1927) was an American physicist and astronomer. She was essential to the founding of the Whitin Observatory at Wellesley College, and was the instructor to several astronomers, including Annie Jump Cannon.
Biography.
Whiting graduated from Ingham University in 1865.
Whiting was appointed by Wellesley College president Henry Fowle Durant, one year after the College's 1875 opening, as its first professor of physics. She established its physics department and the undergraduate experimental physics lab at Wellesley, the second of its kind to be started in the country.
At the request of Durant, she attended lectures at the Massachusetts Institute of Technology given by Edward Charles Pickering. He invited Whiting to observe some of the new techniques being applied to astronomy, such as spectroscopy.
In 1880, Whiting started teaching a course of practical astronomy at Wellesley.
In 1895, as told by biographer Annie Jump Cannon,
An especially exciting moment came when the Boston morning papers reported the discovery of the Rontgen or X-rays in 1895. The advanced students in physics of those days will always remember the zeal with which Miss Whiting immediately set up an old Crookes tube and the delight when she actually obtained some of the very first photographs taken in this country of coins within a purse and bones within the flesh.
Between 1896 and 1900, Whiting helped Wellesley College trustee Sarah Elizabeth Whitin to establish the Whitin Observatory, of which Whiting became the first director.
Tufts College bestowed an honorary doctorate on Whiting in 1905.
Sarah Whiting was also known for supporting prohibition.
Whiting retired from Wellesley in 1916 and was a Professor Emeritus until her death in 1927 in Wilbraham, Massachusetts. She is buried in Machpelah Cemetery in Le Roy, New York, near her now-defunct alma mater, Ingham University.
Writings.
Whiting wrote the textbook "Daytime and evening exercises in astronomy, for schools and colleges".
She was an author of several articles in popular astronomy, including:
She also wrote the obituary for Margaret Lindsay Huggins, "Lady Huggins".
She described her experiences in physics in the Wellesley College News article "The experiences of a woman physicist"
Achievements.
Honors:
Tenures:
Education:


Musca in Chinese astronomy

The modern constellation Musca is not included in the Three Enclosures and Twenty-Eight Mansions system of traditional Chinese uranography because its stars are too far south for observers in China to know about them prior to the introduction of Western star charts. Based on the work of Xu Guangqi and the German Jesuit missionary Johann Adam Schall von Bell in the late Ming Dynasty, this constellation has been classified under the 23 Southern Asterisms (近南極星區, "Jìnnánjíxīngōu") with the names Bee (蜜蜂, "Mìfēng") and Sea and Mountain (海山, "Hǎishān").
The name of the western constellation in modern Chinese is 苍蝇座 ("cāng ying zuò"), meaning "the housefly constellation".
Stars.
The map of Chinese constellation in constellation Musca area consists of:


Beauvais astronomical clock

The Beauvais Astronomical Clock is a nineteenth-century astronomical clock in Beauvais Cathedral in northern France.
History and description.
The clock was built between 1865 and 1868 by Lucien Auguste Vérité. It is 12 metres high, and 6 metres wide.
The 52 dials display the times of the rising and setting sun and moon, the position of the planets, the current time in 18 cities around the world, and the tidal times.
The clock also displays the epact (i.e. age of the moon in days on January 1) and the golden number used in calculating the date of Easter.
The hours and minutes are shown in the large central face which depicts Jesus Christ and the twelve apostles.
An 1886 edition of "Blackwood's Edinburgh Magazine" remarks that: "In the eyes of the neighbourhood the chief wonder of Beauvais is not the cathedral, but the astronomical clock...The mechanical part is admirable. It tells everything which any one can wish to know."