- Star Tales - Pictor (ianridpath.com)
One of the constellations representing technical and artistic apparatus introduced into the southern sky by the Frenchman Nicolas Louis de Lacaille after his observing expedition to the Cape of Good Hope in 1751–52. It lies under the keel of the now-dismembered Greek constellation Argo Navis, the ship of the Argonauts, next to the bright star Canopus. In fact the four brightest stars in Pictor, labelled α, β, γ, and δ by Lacaille, had been catalogued by the Dutch explorer Frederick de Houtman as part of Argo a century and half earlier.
- Absolute magnitude (Wikipedia)
In astronomy, absolute magnitude (M) is a measure of the luminosity of a celestial object on an inverse logarithmic astronomical magnitude scale. An object’s absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it were viewed from a distance of exactly 10 parsecs (32.6 light-years), without extinction (or dimming) of its light due to absorption by interstellar matter and cosmic dust. By hypothetically placing all objects at a standard reference distance from the observer, their luminosities can be directly compared among each other on a magnitude scale. For Solar System bodies that shine in reflected light, a different definition of absolute magnitude (H) is used, based on a standard reference distance of one astronomical unit.