Re: (IAAC) Obj: Albireo (Beta Cygni) - Inst: 102 mm f/9.8 Achromatic refractor

:If Capella was close to the horizon as you mentioned prismatic dispersion
:have caused the color change.

Absolutely!  This effect is very apparent with a low-lying bright star,
such as Sirius.  I am sure Capella looked much yellower (and more stable in
color) as it moved to a higher position.

:Dave Mitsky