In a few cases you have a choice and you can consult the descriptions to see which one you like better.

Remember that a smaller magnitude number is a brighter star, if that is your preference.

66 Alpha is Castor, a bright and well-known star. It is probably the one to choose, although technically 69Upsilon is the correct choice if your year is L or L+1 in the 1950 era.

66Alpha GEM (Castor)
Birthday from Jack’s initial research: July 13
Magnitude: 1.6, 23rd brightest star.
Spectrum/Star type: Whitish
Distance in Light Years: 52
Diameter compared to Sun: System A has Two 2xDIA stars & system B has Two 1.5xDIA stars.
Luminosity compared to Sun: 49 total
Date best observed: Feb 2
Additional information: Six stars!!! The A and B systems (each doubles!) have a period of
445 yrs, and around all of them is a pair of Red Dwarfs that take at least 14,000 yrs to orbit the inner 4! The December Meteor Shower- “The Geminids” radiates nearby on the 13th or 14th-60/hr.
Castor is The Twin on the right, remember it has an “r” in its name! In a large telescope you can only see 2 stars. Castor was a horseman, and was mortal.

69Upsilon GEM
Birthday from Jack’s initial research: July 14
Magnitude: 4.1
Spectrum/Star type: Red Giant
Distance in Light Years: 240
Diameter compared to Sun: 30
Luminosity compared to Sun: 115
Date best observed: Feb 28
Additional information: A double star. Upsilon is dimmer than both Castor and Pollux, but in reality is much larger!