New rig help

[Anthonyexmouth]

Can someone with a better eye/knowledge, take a look at this sub. 

First clearish night with my new Stellamira with the dedicated flattener.

Stars in top right and bottom right look a little off. 

180sec sub of the bubble nebula.

 

Is it guiding - tilt- back spacing, or something else? Bubble Test.fits

 

[ONIKKINEN]

Dont know about tilt and all that, but this sub is well out of focus all over the frame, so hard to advice before that is fixed.

[Anthonyexmouth]

16 minutes ago, ONIKKINEN said:

Dont know about tilt and all that, but this sub is well out of focus all over the frame, so hard to advice before that is fixed.

Really? Looks ok on my screen and the auto-focuser seems to be working ok. Bit of high cloud here

[ONIKKINEN]

7 minutes ago, Anthonyexmouth said:

Really? Looks ok on my screen and the auto-focuser seems to be working ok. Bit of high cloud here

Zoom in really close and you'll see that stars are very slightly hollow. Star size measurements also come up with 10''+ fwhm so yes it is well out of focus.

[CKemu]

12 minutes ago, Anthonyexmouth said:

Really? Looks ok on my screen and the auto-focuser seems to be working ok. Bit of high cloud here

I would have to agree, the whole frame seems soft and out of focus. I popped it in Pixinsight to look for aberration in the corners, and it' hard to tell due to focus.

[Anthonyexmouth]

12 minutes ago, ONIKKINEN said:

Zoom in really close and you'll see that stars are very slightly hollow. Star size measurements also come up with 10''+ fwhm so yes it is well out of focus.

What are you using to measure fwhm? PI is telling me 4.3.

[CKemu]

6 minutes ago, Anthonyexmouth said:

What are you using to measure fwhm? PI is telling me 4.3.

Using the script for FWHM, I am getting 4.410px.

The smaller the FWHM, generally the better, my recent test images from my ATIK490EX / Esprit 100ED gave me 1.34px. Your stars are really out of focus, I would either suggest a Bahtinov mask to tighten the focus, or manually tweak it until that number starts shrinking in your test shots.

Edited September 16, 2022 by CKemu

[Anthonyexmouth]

3 minutes ago, CKemu said:

Using the script for FWHM, I am getting 4.410px.

The small the FWHM, generally the better, my recent test images from my ATIK490EX / Esprit 100ED gave me 1.34px. Your stars are really out of focus, I would either suggest a Bahtinov mask to tighten the focus, or manually tweak it until that number starts shrinking in your test shots.

Odd, auto focus is consistently giving me good numbers. 

[ONIKKINEN]

AstoimageJ seems to have the most realistic FWHM measurements of all the software i have used. Examples below:

Multiple stars seeing profile:

Single star example 1:

Single star example 2:

On the 2 latter examples you can see that the measurement is not that of a focused star. The purple line should reach a point (or just continue upwards) at the top but here it starts to dim down a bit before reaching the true center of the star which means the star is hollow: not in focus.

[CKemu]

1 minute ago, Anthonyexmouth said:

Odd, auto focus is consistently giving me good numbers. 

I don't know what to say, except to disable your Auto Focus and go in manually, your stars are disc like, slightly hollow and not right, and that's just using my eyeballs, HD corrected with glasses and a lot of coffee in my system!

[Anthonyexmouth]

ok, high cloud has cleared a bit now. what about this one?

 

I think it might have been the high cloud earlier. 

 

 

0001 Filamentary Nebula -10.00 120 2022-09-16.fits

 

 

[CKemu]

11 hours ago, Anthonyexmouth said:

ok, high cloud has cleared a bit now. what about this one?

 

I think it might have been the high cloud earlier. 

 

 

0001 Filamentary Nebula -10.00 120 2022-09-16.fits 22.31 MB · 5 downloads

 

 

Yeah, that is a heck of a lot better - the stars aren't doughnut brightness, and smudged in to discs. Glad to see you're getting data! I'm sat looking at clear skies waiting for an adapter to come before I can start making useful data again.