Information:  - Astronomy is a natural science that studies celestial objects and phenomena. It applies mathematics, physics, and chemistry, in an effort to explain the origin of those objects and phenomena and their evolution. Objects of interest include planets, moons, stars, galaxies, and comets; while the phenomena include supernovae explosions, gamma ray bursts, and cosmic microwave background radiation. More generally, all astronomical phenomena that originate outside Earth's atmosphere are within the purview of astronomy. A related but distinct subject, physical cosmology, is concerned with the study of the Universe as a whole.  - The araB gene promoter is a bacterial promoter, activated by e L-arabinose binding.  - WZ Sagittae ("WZ Sge") is a cataclysmic dwarf nova star system in the constellation Sagitta. It consists of a white dwarf primary being orbited by a low mass companion. The white dwarf is about 0.85 solar masses while the companion is only 0.08 solar masses. This implies that the companion is a spectral class L2 star, although this has yet to be confirmed. The distance to this system has been determined by parallax measurements using the fine guidance sense on the Hubble Space Telescope, yielding a distance of 43.5 parsecs.  - The Henry Draper Catalogue ( HD ) is an astronomical star catalogue published between 1918 and 1924 , giving spectroscopic classifications for 225,300 stars ; it was later expanded by the Henry Draper Extension ( HDE ) , published between 1925 and 1936 , which gave classifications for 46,850 more stars , and by the Henry Draper Extension Charts ( HDEC ) , published from 1937 to 1949 in the form of charts , which gave classifications for 86,933 more stars . In all , 359,083 stars were classified . The original HD catalogue covers the entire sky almost completely down to an apparent photographic magnitude of about 9 ; the extensions added fainter stars in certain areas of the sky . The construction of the Henry Draper Catalogue was part of a pioneering effort to classify stellar spectra , and its catalogue numbers are commonly used as a way of identifying stars .  - S Doradus (also known as S Dor) is one of the brightest stars in the Large Magellanic Cloud (LMC), a satellite of the Milky Way. It is a Luminous Blue Variable and one of the most luminous stars known, but so far away that it is invisible to the naked eye.  - A star is a luminous sphere of plasma held together by its own gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye from Earth during the night, appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth. Historically, the most prominent stars were grouped into constellations and asterisms, the brightest of which gained proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. However, most of the stars in the Universe, including all stars outside our galaxy, the Milky Way, are invisible to the naked eye from Earth. Indeed, most are invisible from Earth even through the most powerful telescopes.  - KW Sagittarii is a red supergiant, located approximately 2,400 parsecs away from our Sun in the direction of the constellation Sagittarius. It has a size of (up to by some estimates), making it one of the largest known stars. If placed at the center of the Solar System, the star's surface would engulf Mars.   - The apparent magnitude of a celestial object is a number that is a measure of its brightness as seen by an observer on Earth. The brighter an object appears, the lower its magnitude value (i.e. inverse relation). The Sun, at apparent magnitude of 27, is the brightest object in the sky. It is adjusted to the value it would have in the absence of the atmosphere. Furthermore, the magnitude scale is logarithmic; a difference of one in magnitude corresponds to a change in brightness by a factor of , or about 2.512.  - Astrophotography is a specialized type of photography for recording images of astronomical objects and large areas of the night sky. The first photograph of an astronomical object (the Moon) was taken in 1840, but it was not until the late 19th century that advances in technology allowed for detailed stellar photography. Besides being able to record the details of extended objects such as the Moon, Sun, and planets, astrophotography has the ability to image objects invisible to the human eye such as dim stars, nebulae, and galaxies. This is done by long time exposure since both film and digital cameras can accumulate and sum light photons over these long periods of time.   - A star catalogue (Commonwealth English) or star catalog (American English), is an astronomical catalogue that lists stars. In astronomy, many stars are referred to simply by catalogue numbers. There are a great many different star catalogues which have been produced for different purposes over the years, and this article covers only some of the more frequently quoted ones. Star catalogues were compiled by many different ancient peoples, including the Babylonians, Greeks, Chinese, Persians, and Arabs. Most modern catalogues are available in electronic format and can be freely downloaded from space agencies data center.  - An astronomical catalog or catalogue is a list or tabulation of astronomical objects, typically grouped together because they share a common type, morphology, origin, means of detection, or method of discovery. Astronomical catalogs are usually the result of an astronomical survey of some kind.  - Babylonia was an ancient Akkadian-speaking state and cultural area based in central-southern Mesopotamia (present-day Iraq). A small Amorite-ruled state emerged in 1894 BC, which contained at this time the minor city of Babylon. Babylon greatly expanded during the reign of Hammurabi in the first half of the 18th century BC, becoming a major capital city. During the reign of Hammurabi and afterwards, Babylonia was called "Mt Akkad" "the country of Akkad" in the Akkadian language. It was often involved in rivalry with its older fellow Akkadian-speaking state of Assyria in northern Mesopotamia. Babylonia briefly became the major power in the region after Hammurabi (fl. c. 1792  1752 BC middle chronology, or c. 1696  1654 BC, short chronology) created a short-lived empire, succeeding the earlier Akkadian Empire, Third Dynasty of Ur, and Old Assyrian Empire; however, the Babylonian empire rapidly fell apart after the death of Hammurabi.  - Before the advent of photometers which accurately measure the brightness of astronomical objects, the apparent magnitude of an object was obtained by taking a picture of it with a camera. These images, made on orthochromatic photoemulsive film or plates, were more sensitive to the blue end of the visual spectrum than the human eye or modern photometers. As a result, bluer stars have a lower (i.e. brighter) photographic magnitude than their modern visual magnitude, because they appear brighter on the photograph than they do to modern photometers. Conversely, redder stars have a higher (i.e. fainter) photographic magnitude than visual magnitude, because they appear dimmer. For example, the red supergiant star KW Sagittarii has a photographic magnitude of 11.0 to 13.2 but a visual magnitude of about 8.5 to 11. It is also common for star charts to list a blue magnitude (B) such as with S Doradus and WZ Sagittae.  - Henry Draper (March 7, 1837  November 20, 1882) was an American doctor and amateur astronomer. He is best known today as a pioneer of astrophotography.  - The human eye is an organ which reacts to light and pressure. As a sense organ, the mammalian eye allows vision. Human eyes help provide a three dimensional, moving image, normally coloured in daylight. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth. The human eye can differentiate between about 10 million colors and is possibly capable of detecting a single photon.  - A photometer, generally, is an instrument that measures light intensity or optical properties of solutions or surfaces. Photometers measure:  - American English (variously abbreviated AmE, AE, AmEng, USEng, en-US), also called United States English or U.S. English, is the set of varieties of the English language native to the United States. English is the most widely spoken language in the United States and is the common language used by the federal government, considered the "de facto" language of the country because of its widespread use. English has been given official status by 32 of the 50 state governments. As an example, while both Spanish and English have equivalent status in the local courts of Puerto Rico. Under federal law, English is the official language for any matters being referred to the United States district court for the territory.    Given the information above, choose from the list below the object entity that exhibits the relation 'instance of' with the subject 'henry draper catalogue'.  Choices: - astronomical catalog  - astronomical object  - astronomical survey  - catalog  - catalogue  - city  - cloud  - constellation  - country  - data  - data center  - direction  - distance  - district  - dwarf  - dynasty  - federal government  - fell  - fine  - gene  - government  - human  - instrument  - language  - magnitude  - march  - mass  - mathematics  - natural science  - nova  - november  - object  - organ  - perception  - photograph  - photography  - promoter  - region  - result  - scale  - set  - size  - sky  - space  - sphere  - star  - star catalogue  - star system  - state  - surface  - system  - telescope  - three  - united states district court  - value  - variable  - vision
A:
astronomical catalog