1 Almach (Gamma (a) Andromedae)

Although a close pair separated by 9.4 arcseconds, Almach is not difficult to split. It is the third in a line of bright stars extending eastward from Alpheratz (Alpha (_) Andromedae) in the northeastern corner of the Great Square of Pegasus. From mag. +2.0 Alpheratz, move 7° northeast to mag. +3.3 Delta (b) Andromedae, then a further 8° northeast to mag. +2.0 Mirach. Finally, move 12.5° northeast to find Almach.

The brighter A component is spectral class K3 that appears gold at 63x magnification. The fainter B companion – noticeably dimmer at mag. +4.8 – is actually a triple star system in itself. With all three components in such close apparent proximity to each other (under 0.2 arcseconds) they appear as one blue star to all but the very highest specification amateur equipment. Two of these components are type-B main sequence stars orbiting each other. The other is a type A0 star, which may possibly be the reason they merge to take on a greenish hue at 200x.

Golden Almach and creamy yellow 107 Aquarii both have companions that contribute to a greenish tinge under the right conditions

Almach (Gamma (a) Andromedae) Magnitudes +2.3 and +5.0 Separation 9.4” (This and all similar images are acurate renders)