Lots of lovely little Seagulls. 130 PDS and Collimation

[Terrierist]

Hi All.

I Joined the 130PDS club over the weekend after reading the reviews and seeing the shots with the 'scope. 

I've never seen the Pleiades as beautiful or as sharp and was itching to get a camera on the set up.

When I did, the stars all appeared like little Seagulls, all the way from the centre out to the edges, is this likely to be a collimation issue (with it being a new scope) or is the mount/tripod moving likely to be more the issue?

A little confusing to see such bright stars that appeared sharp through the eyepiece and then the sky looking like Blackpool sea front when I switched to the camera.

I forgot to take an image to display the problem, I apologise.

Looking forward to getting the Cheshire from @FLO when Royal Mail can be bothered to deliver it...

 

Kev

[carastro]

It's probably a spacing issue, have you got a coma corrector?  If so you need to get the spacing right.  though normally this would be more severe towards the corners. 

Shame you didn't get a photo, would make it easier to diagnose. 

Carole 

Edited November 19, 2018 by carastro

[Terrierist]

5 minutes ago, carastro said:

It's probably a spacing issue, have you got a coma corrector?  If so you need to get the spacing right.  though normally this would be more severe towards the corners. 

Shame you didn't get a photo, would make it easier to diagnose. 

Carole 

Morning Carole..

No, no coma corrector at the moment.

 

[david_taurus83]

Tracking? Guiding? You wouldn't notice any minute movements visually through the eyepiece but a camera will record them.

[Terrierist]

4 minutes ago, david_taurus83 said:

Tracking? Guiding? You wouldn't notice any minute movements visually through the eyepiece but a camera will record them.

After looking at what equipment I was using last night, I *think* that this is the answer.

I'd taken my steel (round) legged EQ5 tripod apart for the puck at the top. This has gone to my friends to be incorporated in the pier I am building with his help.

I was using an EQ3-2 tripod (square legged) and noticed it was about as steady as me after six pints.???

Could I be on the right track?

 

[RichLD]

Could be pinched optics, it might be worth checking the tightness of the primary mirror clips. The mirror should be able to move slightly - when tightening the screws, a lot of people put a little bit of thin card inbetween the clip and the mirror, then remove it to leave a very small gap.

It may be that the camera picked up the problem but the mk1 eyeball missed it. Always worth checking anyhow.

[ollypenrice]

I'd read this characteristically excellent article by Jerry Lodigruss. Seagulls are in there!

http://www.astropix.com/html/i_astrop/Diagnosing_Trailed_Stars.html

Which looks like a 'best fit' with your problem?

The fact that a scope is new doesn't mean you should expect it to be collimated after delivery. This is unlikely, alas.

Olly

[Terrierist]

13 minutes ago, ollypenrice said:

 

Which looks like a 'best fit' with your problem?

The fact that a scope is new doesn't mean you should expect it to be collimated after delivery. This is unlikely, alas.

Olly

Hi, Olly, and thanks for the link.

I've got seagulls everywhere! I'll have to wait for the collimator to arrive and see what I can find with that, but I do think that the EQ3-2 Tripod the scope and mount were attached to last night certainly added to the issue.

[Steve1984]

Hi Terrierist,
Did you ever get to the bottom of your seagull stars issue? I am having the same issue with my 8" Newtonian and can't seem to get to the bottom of it. I have collimated the hell out of it and still can't seem to resolve the issue. My seagulls originated after I had taken the primary mirror out to center spot it and it's been there ever since.

Would love to here how you resolved your issue.

 

Many thanks,

Steve