Guiding Woes sorted at last... :-)

[JohnP]

Well I have finally got to bottom of my guiding (drift) issues. As you all probably know I have issues where although guiding works fine but I get shift between the subs. I had tried everything to eliminate the problem which although didn't really effect images too much the stars were marginally mis-shaped which obviously means I must also be loosing detail in what I am imaging. Some of the things I tried were different telescopes, different mount methods (ontop V's side-by-side), all the different guide progs going, polar alignment, drift alignment, guide rings & probably other things as well.

Well last night I borrowed Jim's (thanks mate) OFF AXIS GUIDER. I attached to ED80 with my imaging camera. I had only ED80 on my mount. I did a very quick polar alignment (didn't bother with drift or anything) & then set up focus on the OAG (a little tricky at first but not too bad). I then pointed at a random area of sky calibrated my guide prog (Guidemaster) & off I went. I did 4x5mins & 3x10mins. I couldn't believe difference every sub downloaded right ontop of previous (no drift) & had perfectly round stars. Below are stacks of the 7 images I took (50mins total). The first stack I have aligned the individual subs with 2-star alignment & the second is with no alignment at all - I just stacked the subs one on top of each other. If I had done this previously with my setup I would have had horrible eggshaped stars.

Anyway I am well chuffed - Can't wait to try an image something with the new setup.

Cheers, John

[Mike]

Sounds like the problem may have been flexure then.

What is the OAG model you used?

[JohnP]

Yep definitely even though I had what I thought was a rock solid setup something was still moving. I even eliminated the mirrors by trying different scopes for guiding - It really did my head in. Anyway if last night wasn't a fluke then the OAG is definitely the way to go. The one I borrowed off Jim is the BrightStar one from Bern - He is selling them for £94 - You need something like 30mm of back focus to insert it but no probs for ED80 (might be for reflectors).

John

[RobertM]

I think a lot of trouble is with the focuser, even the Moonlite's have some movement though I wouldn't have expected that much with a light camera like your's.  Anyway, whatever the cause, the results speak for themselves.

Well sorted !!!

Robert

PS. Of course we'll be expecting even better images...

[JohnP]

PS. Of course we'll be expecting even better images...

I flippin hope so the amount of grief it has given me. Even though my images are OK the mis-shapen stars were really bugging me & were obviously loosing detail in image. At least now I know image quality should be down to seeing/ light pollution & not hardware.

Cheers,  John

[mickw]

Nice result John

[JohnP]

Cheers Mick - Yep think it is the best I have EVER had for 10min subs... fingers crossed next time I image something.  Good luck for tonight - John

[Mac]

Nice to finally get to the bottom of things,

Mac.

[JohnP]

Ta Mac - John.....

[Rocket Pooch]

Out you go then its clear tonight

[MarkS]

Excellent news John.  I'm just a bit concerned for Jim - what will he do without his OAG?

[JohnP]

Cheers Mark.

Jim doesn't use his OAG so no probs... 

Seriously though I am going to get one - Jim's one is <£100 so may get same model. If it is clear tonight I may test it on a DSO.

Cheers,  John.

PS - Any joy down in France - did you manage any imaging at all?

[RobertM]

There's one on uk astro buy sell for £65...

[JohnP]

Oh cheers Robert will take a look - John

[RobertM]

I think he's marked it as Pending now as it looks to be the same as this one on eBay which has just under two hours to go (he can't withdraw with less than a day to go):

eBay link

Robert

(Edit - URL inside tags, hopefully -- Rick)