Problems wit Orion OAG

[E_ri_k (Erik)]

Hey everyone, I have been having trouble with my Orion OAG and GSO RC10. I managed to collimate the scope on Achernar tonight, then moved on to setting up the OAG. Got my imaging camera focused, and then after a lot of mucking around trying to find a star, got a reasonable focus in the guide camera.

The problem is the stars in the guider are very oval, and I can't get them into sharp focus. Did a bit of a google search, and found some stuff about field curvature becoming a problem the further away the guide chip is from the pick off prism.

Any thought on correcting this, or is it just one of those things you have to live with???

Not to sure how it's effecting guiding because it's been blowing like mad outside, and the corrections being made in Maxim are quite large, but a 60 second exposure produces pretty round stars still.

Erik.

[Visionoz (Bill)]

Erik

FWIW I normally ignore the cigar-shaped "guide" star and just guide - with modern software/guide imagers as I understand it, they can guide based on the centroid so it works!

HTH
Cheers
Bill

[E_ri_k (Erik)]

Thanks for that reassurance. After 90 minutes of trying to space and focus the OAG I felt like I just took 10 steps backwards when I saw the oval stars.
I guess it did guide OK, but ti was hard to tell because of the crazy wind.

Erik

[Marke (Mark)]

It cant be avoided sometimes as you are picking off stars at the very outer edge of your FOV , making them prone to feild curvature.