Image of the day

Captured by
Terry Wood

Jupiter (clearer) Nov 5th 2023 w/Mewlon 180c

My Account

New to Astromart?

Register an account...

Need Help?

Colimination of Achromatics

Started by qbose, 10/31/2012 11:44AM
Posted 10/31/2012 11:44AM Opening Post
Recently I had to Coliminate my 6" CR150 (trying for perfection) and in looking for a decent star I stumbled on the best one to use!

Betelgeuse!!!

Because it's red the center is more defined when you defocus the star and it's more apparent how centered the optics are. Must have to do with the fact that the achromatics have color and so red Betelgeuse is more defined and does not blend in like a normal white star however bright it may be as Sirius was not as good. Believe me it's the best! Use Betelgeuse and you will have a much easier time getting closer to perfection. Once you get perfect the color seems to go away on axis or is at least is less noticeable in this particular scope.

Regards,
Greg
Posted 11/01/2012 02:37AM #1
Great tip. Thank you!

Maybe Antares could be substituted during the warm months?