Final tweaks before I'm fully dialed in?

[TiffsAndAstro]

After 3ppa in Nina and focusing main and guide scopes and recalibrating phd2 I took the attached pic. It's 23 x 180sec but clouds arrived full calibration frames. It's cropped and a quick post process (which I over did).

My guiding was around 0.18 (1.6) in Nina. I think I could improve that with more medelling and maybe resorting to the backlash in Dec axis via a physical screw, but I'm not keen. It's possible my 3ppa was too accurate. Are the above numbers good enough for my gear?

Also, hfr in phd2 was in red and over 4 most of the time and the zoom on guide star looked a bit big. Is this likely guide scope focus related? I have not changed gain control in phd2 think it defaults to 48.

I also noticed one egg shaped star in top left but not really anywhere else in stacked image (not visible in the attached crop image). Likely a result of stacking not back focus?

Lastly, there's a button in siril I think measures tilt and the top left of the quad overlay seems about 20% more than the other 3 which usually seem less than 10% different. Can a sensor tilt in just one corner, rather than in a plane?

Sorry for continually asking more questions and requests for help. I do think I'm acting on them all and putting them to good use, but I might be a tad bias

 

 

 

 

 

Edited April 25 by TiffsAndAstro
Wrong galaxy pic attached. Easy mistake to make :)

[ONIKKINEN]

Before jumping to conclusions on sensor tilt you should attempt to eliminate all other sources of tilt. This could be focuser tilt or collimation (really these 2 are kind of the same thing). Its not a stacking problem, Siril has some fancy algorithm that will twist and turn every sub to match the reference frame, so all problems in a stack are things that are due to some issue with the scope/kit.

That said, adjusting that tilt away can be tricky so up to you whether you can live with that or not. BlurXterminator would certainly fix that, but it kind of costs an arm and a leg since you also need Pixinsight so probably not the solution you were looking for.

For your guiding its hard to say where the issue is without seeing the guide log. If you want to you could share the guide log for us to look at (just drag and drop it to the attachments, same way you do with images).

* Based on the image i would not actually bother tweaking anything, looks good. You can easily make things worse with tilt adjustments.

Edited April 25 by ONIKKINEN
*

[Elp]

Or do what I do, just crop it out. You can drive yourself crazy trying to fix tilt. Cropping suits me because I setup and breakdown pretty much every session so it'd be a futile exercise for me. It presents an issue if you want to do mosaics, but then again just use a larger overlap to mitigate it.

Edited April 25 by Elp

[TiffsAndAstro]

44 minutes ago, ONIKKINEN said:

Before jumping to conclusions on sensor tilt you should attempt to eliminate all other sources of tilt. This could be focuser tilt or collimation (really these 2 are kind of the same thing). Its not a stacking problem, Siril has some fancy algorithm that will twist and turn every sub to match the reference frame, so all problems in a stack are things that are due to some issue with the scope/kit.

That said, adjusting that tilt away can be tricky so up to you whether you can live with that or not. BlurXterminator would certainly fix that, but it kind of costs an arm and a leg since you also need Pixinsight so probably not the solution you were looking for.

For your guiding its hard to say where the issue is without seeing the guide log. If you want to you could share the guide log for us to look at (just drag and drop it to the attachments, same way you do with images).

* Based on the image i would not actually bother tweaking anything, looks good. You can easily make things worse with tilt adjustments.

ok this ties in with a lot of my thinking atm. perhaps in the future, when i need just a little improvement to beat hubble ( ) i maybe look at any minor tilt issue i have. 

guiding, ill have another go tonight, hopefully,  and share a log, but i was hoping 0.18 (1.5) ish would be ok considering my pixel scale and my other gear. 

i'm using astro sharp in my 'work flow' now and it seems an improvement over not using any blur related software. i doubt its as good as blurxterminator though. 

also looking at my subs there were some plane trails in it. not sure if doing 3 minutes over 2 minute subs is a big advantage for me shooting in colour. 

[TiffsAndAstro]

42 minutes ago, Elp said:

Or do what I do, just crop it out. You can drive yourself crazy trying to fix tilt. Cropping suits me because I setup and breakdown pretty much every session so it'd be a futile exercise for me. It presents an issue if you want to do mosaics, but then again just use a larger overlap to mitigate it.

to be honest, if i can maybe see some tilt in only very far corners, this is the perfect solution for me really. i mean, i usually crop in at least 5 maybe 10 pixels or more as routine anyway

i forgot KISS, sorry

[Elp]

Depends on the individual. If someone say buys a full frame sensor camera, they're going to want the full frame looking good. But me personally, I think defects such as lens issues, noise etc just shows that a person took the image via their equipment, completely smooth images look unnatural to me for example, all digital media generally has noise due to how electronics work.

[TiffsAndAstro]

3 minutes ago, Elp said:

Depends on the individual. If someone say buys a full frame sensor camera, they're going to want the full frame looking good. But me personally, I think defects such as lens issues, noise etc just shows that a person took the image via their equipment, completely smooth images look unnatural to me for example, all digital media generally has noise due to how electronics work

I still want to try cloning over some areas in the starless output from starnet. Just to see any effect on how far I can stretch. Just need a way to see un stretched tiff in gimp without stretching it

[Elp]

I don't think you can. Why not just stretch it and clone stamp that image. I always do the cleanup after stretching.

[900SL]

I think i read that Siril tilt needs a uniform starfield to work. It averages FWHM in center and 4 corners or something, so can be thrown out by irregular star background.

The best check by the way is to use your eyes, rather than fussing over numbers. Egg shaped? Star trails? Looks OK full screen? Good to go. Don't pixel peep, especially with junk gear to start with.

[TiffsAndAstro]

2 hours ago, Elp said:

I don't think you can. Why not just stretch it and clone stamp that image. I always do the cleanup after stretching.

i was hoping to clone over some areas in the starless output from starnet++ before stretching that same file. if i clone after i stretch, i will be cloning more noise. at least that's how i see it in my head i just want to try it out.

im not sure how i'd find which bit to use to clone over other bits, before stretching in gimp, without that changable view option siril has (linear, auto stretch histogram etc). 

Its possible i can copy the initial layer to a new layer, stretch one as a guide for me on the unstretched layer? then delete the guide/stretched layer?

Edited April 25 by TiffsAndAstro

[Elp]

The starless image will have noise regardless so there's no issue cleaning up a stretched image as they'll be noise everywhere anyway.

 

[PhilB61]

Image looks great, just needs lots more total exposure time to reduce the noise. 

My experience using clone and heal tools is that it's best to do so after stretching your image. If you do it on linear data, initially it may look better but when you later stretch the image, the clone/heal "repairs" stand out like a sore thumb. 

I have not found a way to do a temporary screen stretch in GIMP to assist in working on linear data, and would also be interested in hearing of any way of doing the this.

[TiffsAndAstro]

58 minutes ago, PhilB61 said:

Image looks great, just needs lots more total exposure time to reduce the noise. 

My experience using clone and heal tools is that it's best to do so after stretching your image. If you do it on linear data, initially it may look better but when you later stretch the image, the clone/heal "repairs" stand out like a sore thumb. 

I have not found a way to do a temporary screen stretch in GIMP to assist in working on linear data, and would also be interested in hearing of any way of doing the this.

Well I failed with my idea of having two layers, one stretched by me as a guide layer but I'll try again later. I couldn't add two layers lol  it kept replacing one.

I think you're correct about the effect of cloning, I just wanted to try for myself and see.

will update if I get it working in some way.

[TiffsAndAstro]

No clear skies so I've sorted my wiring

It's not perfect lol but an improvement. Shockingly everything seems to work.

Should I lose the pier and use the leg extensions or just leave it as it is? Seems fairly stable this far like the pic.

[Elp]

I don't think you'll have the clearance for the Canon so best to keep the pier in.

[michael8554]

The image looks pretty good.

1.  "hfr in phd2 was in red and over 4 most of the time "

Do you mean HFD ?

Use the HFD figure in the PHD2 Star Profile window to improve focus.

2.  "I've sorted my wiring"

I hope that's the "before "image.  :-<

All the cables bunched with the blue USB are pulling on the mount, which may affect guiding.

Also the cable joins are being pulled apart so may become intermittent, particularly the blue USB into the hub.

You may need some longer cables to avoid that. 

The dew heater cables and the dummy battery cable should be gathered with the rest of the OTA cabling and attached to the OTA, before continuing onwards.

Then gathered into a smooth loop attached to say, one of the the green knobs on the mount.

Make sure that loop doesn't snag anywhere the OTA may point.

3.  The mains setup has no protection for damp, dew, or unexpected rain.

And a mains cable drum should always be fully unwound.

Michael

 

[TiffsAndAstro]

16 hours ago, Elp said:

I don't think you'll have the clearance for the Canon so best to keep the pier in.

Yeah a quick measure and it looks marginal, my "sorted" wiring doesn't help. Need to sort the wiring even more

[TiffsAndAstro]

3 hours ago, michael8554 said:

The image looks pretty good.

1.  "hfr in phd2 was in red and over 4 most of the time "

Do you mean HFD ?

Use the HFD figure in the PHD2 Star Profile window to improve focus.

2.  "I've sorted my wiring"

I hope that's the "before "image.  :-<

All the cables bunched with the blue USB are pulling on the mount, which may affect guiding.

Also the cable joins are being pulled apart so may become intermittent, particularly the blue USB into the hub.

You may need some longer cables to avoid that. 

The dew heater cables and the dummy battery cable should be gathered with the rest of the OTA cabling and attached to the OTA, before continuing onwards.

Then gathered into a smooth loop attached to say, one of the the green knobs on the mount.

Make sure that loop doesn't snag anywhere the OTA may point.

3.  The mains setup has no protection for damp, dew, or unexpected rain.

And a mains cable drum should always be fully unwound.

Michael

 

1 I'm finding focusing my guide scope to be difficult. I can see them in PhD display and the clunky zwo app is as bad. Could I attempt it by changing focus and monitoring the hfr value?

2 no that's pic is after I sorted the wiring, and, as you observed, the blue usb is dragging it down. Will have a go later see if I can do as you suggest. At least somewhat anyway.

3 the mains cable has some red button thermal cutout. Not sure how Id protect it like you say except maybe a plastic bag didn't know to fully unwind it. Could be a trip hazard in dark though.

Ty v much for all that feedback it's really appreciated.

my guiding was ok, but a bit worse than last session - probably a combination of my guide focus and the dragging usb cable. Mount did do a proper meridian flip for the first time - i made the wait before/after values a bit more conservative. it loses me 10 mins of imaging time, but it seemed to work fine so im not changing that. 

Edited April 28 by TiffsAndAstro

[michael8554]

"Could I attempt it by changing focus and monitoring the hfr value?"

Again, I don't know what you mean by hfr.

Do you mean HFD ?

Monitor that as you alter the focus.

Michael

[TiffsAndAstro]

53 minutes ago, michael8554 said:

"Could I attempt it by changing focus and monitoring the hfr value?"

Again, I don't know what you mean by hfr.

Do you mean HFD ?

Monitor that as you alter the focus.

Michael

i think its half flux radius? nina displays it in the image pane for last/current image taken in the sequencer and phd2 also shows it and colour codes it - above about 4.5 it shows as red?

also shows on the graph of number of stars and hfr ?

Edited April 28 by TiffsAndAstro