What is the difference between omega constellation women's watch 1262.30.00 and 1272.30.00?
The 1272 is a 25 mm case while the 1262 is a 22.5 mm case. The 1272 is the ladies Constellation whil ethe 1262 is the Ladies Constellation Mini Leigh Ross
A constellation (in casual usage) is an imaginary pattern composed of a group of several stars. Strictly speaking, astronomers would call such a pattern an "asterism", and use the term "constellation" to mean "a specifically designated patch of sky". This patch of sky will, of course, contain many stars.