Itâs Not the Needle That Hurts. I believe the pain is due to the solution used to clean the eye prior to the injection and not the needle itself. The solution is called âBetadineâ and is commonly used to cleanse the eye prior to intraocular injection. Most retina specialists use this a part of their routine.
For numerical convenience, an object brighter than 0th magnitude has a negative magnitude; the brightest star, Sirius is magnitude -1.4; the full moon is magnitude -13, and the Sun is a blazing -26th magnitude.
Astronomers define star brightness in terms of apparent magnitude (how bright the star appears from Earth) and absolute magnitude (how bright the star appears at a standard distance of 32.6 light years, or 10 parsecs). Astronomers also measure luminosity â the amount of energy (light) that a star emits from its surface.