Castor is a system that looks like a pair of cats eyes at high power consisting of a pair of magnitude 1.9 and 2.9 white stars with only 3" separation. There is a third star in the system which can be seen of magnitude 8.8, this star is very red by its spectra but I didn't see any colour.
Delta
Delta was a nice double though due to the magnitude difference between the two stars (A=3.5,B=8.2) the companion was more difficult to view than it should have been. Visually Delta was itself pale yellow in colour and the companion 5.8" away was deep orange.