First guided image

[spectre]

I think I’ve finally got my guiding under control. This is 54 min of 180 sec subs with the equipment in my sig. 20 Darks, flats, and bias used for calibration. Captured with BYEOS and processed in PS. Now that I don’t have much trailing I’m seeing other problems. Any ideas what’s causing the strange stars around the edges of my image? Collimation, flexure, field rotation? I’ve no clue. Any help would be appreciated.

Thanks All and clear skies.

[rfdesigner]

First up not a bad first go, you've hit the ground running.

looks like a combination of field rotation and coma.

Take a look at the individual subs.. if you see the corner stars to be much less streaked in single shots then your alignement stage in processing isn't rotating images to fit, it's just shifting them left/right and up/down. There should be an option to align at a higher order.

Do you have a coma corrector?.. if so then I would suggest collimation is out a touch too.

Also I think your flats have problems, I can see a distinct rectangle in your posted image which is likely to happen if the flats were in some way out. Flats are possibly one of the hardest things to get right.

Derek

[Daniel-K]

i thinks its a great start i agree about the flats, i had a play in ps3 just done a simple high pass filter and some simple curves,, it looks like comma on the edge but i think you can just crop it out untill you get a coma correcter. also i have heard that darks already contain bias and if you take bias your just adding more noise into the image dont know how true that is and darks work better on a odd number

[spectre]

Thanks Derek and Daniel,

I'm struggling with flats but this image is way better with the flats I've got so.....

The individual subs look just like this so it's not DSS doing something strange with the rotation.

I'll try DSS again without the bias and see if the noise improves(odd # of darks too)

I have a Celestron .63 FR/FF but not a coma corrector. I'll have to check collimation again, too.

I have a CG5-ASGT and I did the 2-star/4-star calibration routine and then the PA routine from the handset.

Then I shut everything down and went through the alignment routine again. It said my PA was 00 across the board.

Should I get rotation after going through that alignment procedure?

[rfdesigner]

Thanks Derek and Daniel,

I'm struggling with flats but this image is way better with the flats I've got so.....

The individual subs look just like this so it's not DSS doing something strange with the rotation.

In which case you should put some more emphasis on the physical polar alignment, which usually means doing a bit of drift alignement

(mount 'computer' alignement with 2 or 3 stars isn't going to help you, it's all down to just how precisely the mount is aligned to the earths axis that counts)

Derek