AST-1001 Lecture Notes - Lecture 1: Right Ascension, Orbital Inclination, Ecliptic
Document Summary
Chapter 2: a user"s guide to the sky. In ancient times, constellations= brightest stars that appeared to form groups. Position in the sky told stories handed down from generation to generation over thousands of years. Constellation stars only appear to be close to one another, have a projection effect, and may be located at very different distances from earth. Irrespective of presence or absence of bright stars in those regions. Alpheratz is shared between the andromeda and pegasus constellations. Sirius is the brightest star in the night sky. Stars are named by a greek letter according to their relative brightness within their constellation. The alpha star in one constellation doesn"t have to be as bright as the alpha star in another. First magnitude stars appear 100x brighter than sixth magnitude stars. One magnitude difference gives a factor of 2. 512 in apparent brightness; non-linear scale. The magnitude scale system can be extended; negative numbers are brighter than positive numbers.
