Collimation Issues?

[Scott Tilley]

Hi, would be grateful if someone could confirm that this image's issues are due to collimation? Had a go at M13 last night and this was the result, don't think the scope has been knocked (or no-ones owning up to it!) If it isn't collimation then perhaps the title of the thread should have been "where did all the comets come from:D"

Shot was about 20 seconds single exposure on motorised EQ5 mount. Also tried shots as low as 3 seconds but with same effect.

Help much appreciated!

Scott

[Peter Drew]

Hello Scott. If the comatic images were from miscollimation the tails would all be in the same direction. From your photo it appears that they are radial suggesting that it is field coma. What optical system were you using?

[Breakintheclouds]

Scott,

Were you flying towards M13 very very fast?

[Doc]

It's defintely not collimation. I think it's coma, this makes stars at the edge of the field look like blurry comets whose tails point out radially from the centre of the field.

Problem is yours look pretty bad. I think you will need a coma corrector.

[Scott Tilley]

Thanks All! Peter this was taken through skywatcher 200p and Baadar zoom eyepiece with canon 50d attached. I will have a go tonight and try with and without the eyepiece to see if this is causing the problem.

Cheers

Scott

[Breakintheclouds]

Ah! The zoom eyepiece might explain it. When I looked at buying one of these for my own 200P, people on this forum did warn me that for a fast scope I could expect to see a lot of coma with the Baader zoom. Unfortunately, it looks like they were right.

Hopefully Doc's suggestion of a corrector might sort you out for photography, though.

[Scott Tilley]

Hi All, thanks for your advice, it was the zoom eyepiece! Took this out of the equation last night and problem solved.

Thanks

Scott