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Focus issues? Absolute beginner.

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#1 Whendewsday

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Posted 06 October 2024 - 05:31 AM

I recently got an AP rig for DSO imaging. I am an absolute beginner to AP, and photography in general. I think I have focus issues still. Rather than go down too many rabbit holes, I figured asking here was the best route first. I'm close...I think...

 

I'm working in ASIAIR and my stars have trails after not much exposure time. After my first 300s exposure, I realized the EAF was not on so I thought that was the trick. After turning on EAF, the images got way worse! I do have a Bahtinov mask, so I tried that again and was able to see the 3 spikes crossing correctly but the spikes were very small compared to other images I've seen online. They were also pretty far away from the star itself, if that matters. I was able to focus (I thought) and get plenty of detected stars around 2.2 in size. Any suggestions would be amazing!  

 

Here is a link to 4-5 images: https://drive.google...lf?usp=sharing 

 

This is all ZWO hardware paired with the Askar 71f, and W.O.'s newer 50/200 guide scope.  



#2 Bob2023CL

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Posted 06 October 2024 - 05:47 AM

It looks like your mount isn't tracking?  Can you describe what mount you are using?



#3 Whendewsday

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Posted 06 October 2024 - 05:49 AM

It looks like your mount isn't tracking?  Can you describe what mount you are using?

AM3. I am able to get it to sync and it stays solid red, but after I GoTo and start shooting I did notice it's blinking red.

 

Edit: No issues with plate solving or polar alignment either.


Edited by Whendewsday, 06 October 2024 - 05:52 AM.


#4 Tapio

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Posted 06 October 2024 - 05:51 AM

What mount?
And if it's equatorial then have you done polar alignment?

#5 Whendewsday

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Posted 06 October 2024 - 05:52 AM

What mount?
And if it's equatorial then have you done polar alignment?

AM3, just edited the message but no issues with polar alignment.



#6 maxsid

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Posted 06 October 2024 - 06:05 AM

-- start

-- if out of focus - focus

-- polar align

-- slew to a couple of places and plate solve to have the sky model roughly built

-- set/calibrate the guider - near equator/meridian

-- go to target

  - plate solve

  - focus

  - start imaging


Edited by maxsid, 06 October 2024 - 06:08 AM.


#7 Whendewsday

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Posted 06 October 2024 - 06:21 AM

-- start

-- if out of focus - focus

-- polar align

-- slew to a couple of places and plate solve to have the sky model roughly built

-- set/calibrate the guider - near equator/meridian

-- go to target

  - plate solve

  - focus

  - start imaging

I am able to do all of this but I must not have guiding set correctly? 



#8 soojooko

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Posted 06 October 2024 - 06:47 AM

I do have a Bahtinov mask, so I tried that again and was able to see the 3 spikes crossing correctly but the spikes were very small compared to other images I've seen online.

Masks don't work very well on average stars using short exposures. You need to go-to a big bright star - then you'll see the nice long spikes we all love!


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#9 kathyastro

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Posted 06 October 2024 - 07:14 AM

Your focus doesn't look terrible.  I'd say, leave the focus issue for now and focus on the elephant in the room: the star trails.

 

The trails I see in your images are discontinuous.  Your mount appears to be moving in jumps.  That means the gears are out of adjustment, you bumped it, or you have really bad backlash.  Something mechanical, anyway.

 

If those are stacked images, it could be that the frames didn't register properly.  That could be caused by the software registering on hot pixels instead of stars.  From what I am seeing, though, I think this is less likely.


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#10 Bob2023CL

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Posted 06 October 2024 - 09:35 AM

Can you provide a picture of your setup?  How heavy is your rig?  Can you provide a description of the components?



#11 Whendewsday

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Posted 06 October 2024 - 10:35 AM

Can you provide a picture of your setup?  How heavy is your rig?  Can you provide a description of the components?

Here you go: https://drive.google...iew?usp=sharing

 

After removing all of the gear off the mount, the gear weights 11 lbs on the scale out of the maximum of ~18 lbs for the mount, without counterweight.

 

AM3 mount, TC40 tripod, Askar 71f (no reducer yet), Willams Optics 50/200mm guide scope, ZWO EAF, ASIAIR Plus, ZWO 2600MC and ZWO 120mm mono guild scope. I also happened to ruin an Optolong filter already too (yay), so I removed my filter drawer and set up the imaging train based on the Askar manual. 

 

After seeing what maxsid said earlier in this thread, I don't think my guide was working. I had no error corrections showing in the bar graph history for RA and DEC, no lines at all even. I found this link and wondered if this is my issue? https://eastwindastr...aggression.html and would this cause issues with my mount tracking and see trails?



#12 kathyastro

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Posted 06 October 2024 - 10:50 AM

After seeing what maxsid said earlier in this thread, I don't think my guide was working.

That certainly would explain the trails in your images.  We'd need to see your guide log to know what was going on, but it should have been making corrections that would show up in the graph.



#13 DeepSky Di

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Posted 06 October 2024 - 11:02 AM

That blog is good - it stopped posting for a while and started again. 

 

In the guiding setup, are you seeing stars in the guide camera image? Is it focused? Are there red and blue lines in the graph? What numbers? The correction lines can be turned on and off on the ASIAIR guiding page.

 

Has the guiding been calibrated and is the calibration showing right angles between RA and DEC?

 

If these questions are confusing, I'm looking for screenshots or video ...



#14 idclimber

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Posted 06 October 2024 - 11:16 AM

Here you go: https://drive.google...iew?usp=sharing

 

After removing all of the gear off the mount, the gear weights 11 lbs on the scale out of the maximum of ~18 lbs for the mount, without counterweight.

 

AM3 mount, TC40 tripod, Askar 71f (no reducer yet), Willams Optics 50/200mm guide scope, ZWO EAF, ASIAIR Plus, ZWO 2600MC and ZWO 120mm mono guild scope. I also happened to ruin an Optolong filter already too (yay), so I removed my filter drawer and set up the imaging train based on the Askar manual. 

 

After seeing what maxsid said earlier in this thread, I don't think my guide was working. I had no error corrections showing in the bar graph history for RA and DEC, no lines at all even. I found this link and wondered if this is my issue? https://eastwindastr...aggression.html and would this cause issues with my mount tracking and see trails?

I am posting the above photo of your setup so others can more easily see what you have setup. My assumption is you have not quite figured out how to post an image here given the size restrictions. 

 

IMG_0963.jpeg

 

Based on this I think you also have some cable drag preventing the mount from freely moving. The rats nest of wires up top won't hurt, but any that are between the base of the mount and the equipment above will be. 

 

My first thoughts are on the 300" subs. You can drop that to 30 or 60" for now. If you have a narrowband filter, remove it. You don't need or want any filter on this camera for now. This will shorten the feedback interval on your primary issue, getting the mount properly tracking and guiding. You should also be using gain 100 with that camera. Set the temperature just below your lowest expected during the night. Colder is not better. 

 

Your issue on guiding is very similar to one earlier this week. You do not have the guide software calibrated so the Air knows which way to command movement on the mount. The software must know where up down and left right are relative to the guide camera. Review the instructions, and make that your primary mission you next session. 

 

If however the above frustrates you in the dark, consider skipping the guiding project for the night. Point the scope at any target and take 30" exposures. You can even drop this to 15" as long as you do have additional filter installed. Take 20 to 30 of these and you have a basic image. They won't be perfect but that is ok. You can alternatively put the Air in live stacking mode.

 

Once you get the tracking working you can put your energies into refining the focus. You have a focus motor. You do not need a focus mask. The Air will focus for you, and more accurately than you can with the mask. Review the instructions. If you want feedback on the sub and how well the focus, tracking etc are upload a couple of those raw files to a shared drive and post a link. 


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#15 DeepSky Di

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Posted 06 October 2024 - 11:19 AM

Here's Peter Zelinka's ASIAIR workflow tutorial: https://youtu.be/ffc...UoYXNfwOBlD22_m - guiding is illustrated at minute 19 approx.

 

I have some comments on this

- 3 seconds is a bit long for guiding exposure with a strain wave mount. I use 1s or 0.5s if there's enough light in the guide camera. However this is not a showstopper

- use Centigrade not Fahrenheit because... 

- the camera cooler can cool -35C below ambient. -20C will only be reached if the temperature is below +15C (which is 59F). More cooling also takes more power, and power in AP is limited by power supplies and batteries. I cool to 0C in summer and -10C in winter. The key is to have the camera running at a controlled temperature to match with darks. However, for the 2600 and 533 sensors there's a debate about how important dark calibration is. It may not make a noticeable difference - but taking darks twice a year and saving just the masters is all that's necessary so why not. Also not a showstopper for guiding issues.



#16 Whendewsday

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Posted 06 October 2024 - 11:26 AM

That blog is good - it stopped posting for a while and started again. 

 

In the guiding setup, are you seeing stars in the guide camera image? Is it focused? Are there red and blue lines in the graph? What numbers? The correction lines can be turned on and off on the ASIAIR guiding page.

 

Has the guiding been calibrated and is the calibration showing right angles between RA and DEC?

 

If these questions are confusing, I'm looking for screenshots or video ...

I am able to see stars in the guiding setup. I can also click on a group of stars and it seems to zoom in on them. But my guide graph in ASIAIR, such as the very first one on that blog link, never showed any red or blue lines. I don't recall seeing any numbers either.I want to swear up and down it said 'guiding' but I don't have a screenshot from last night, and maybe I hit stop too, who knows.

 

In the guide camera settings, I haven't adjusted the values yet there for calibration, Max DEC or Max RA since I just found this blog this morning. The defaults are still 2000 for calibration, 500 for Max DEC and Max RA durations. I'll update those values tonight for the 120mm mini guide scope and grab a screenshot if there are still issues.

 

Would this fix my tracking issue with trails?



#17 Whendewsday

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Posted 06 October 2024 - 11:31 AM

I am posting the above photo of your setup so others can more easily see what you have setup. My assumption is you have not quite figured out how to post an image here given the size restrictions. 

 

attachicon.gif IMG_0963.jpeg

 

Based on this I think you also have some cable drag preventing the mount from freely moving. The rats nest of wires up top won't hurt, but any that are between the base of the mount and the equipment above will be. 

 

My first thoughts are on the 300" subs. You can drop that to 30 or 60" for now. If you have a narrowband filter, remove it. You don't need or want any filter on this camera for now. This will shorten the feedback interval on your primary issue, getting the mount properly tracking and guiding. You should also be using gain 100 with that camera. Set the temperature just below your lowest expected during the night. Colder is not better. 

 

Your issue on guiding is very similar to one earlier this week. You do not have the guide software calibrated so the Air knows which way to command movement on the mount. The software must know where up down and left right are relative to the guide camera. Review the instructions, and make that your primary mission you next session. 

 

If however the above frustrates you in the dark, consider skipping the guiding project for the night. Point the scope at any target and take 30" exposures. You can even drop this to 15" as long as you do have additional filter installed. Take 20 to 30 of these and you have a basic image. They won't be perfect but that is ok. You can alternatively put the Air in live stacking mode.

 

Once you get the tracking working you can put your energies into refining the focus. You have a focus motor. You do not need a focus mask. The Air will focus for you, and more accurately than you can with the mask. Review the instructions. If you want feedback on the sub and how well the focus, tracking etc are upload a couple of those raw files to a shared drive and post a link. 

Thanks for the reply. That image was from 4 days ago or so when it was first setup. The cabling is much more loose now and I've monitored it when slewing to targets. I can't be for sure it won't snap on a meridian flip since I haven't gotten that far yet. It seems everything is pointed back to guiding being the problem for me.



#18 Whendewsday

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Posted 06 October 2024 - 11:41 AM

Here's Peter Zelinka's ASIAIR workflow tutorial: https://youtu.be/ffc...UoYXNfwOBlD22_m - guiding is illustrated at minute 19 approx.

 

I have some comments on this

- 3 seconds is a bit long for guiding exposure with a strain wave mount. I use 1s or 0.5s if there's enough light in the guide camera. However this is not a showstopper

- use Centigrade not Fahrenheit because... 

- the camera cooler can cool -35C below ambient. -20C will only be reached if the temperature is below +15C (which is 59F). More cooling also takes more power, and power in AP is limited by power supplies and batteries. I cool to 0C in summer and -10C in winter. The key is to have the camera running at a controlled temperature to match with darks. However, for the 2600 and 533 sensors there's a debate about how important dark calibration is. It may not make a noticeable difference - but taking darks twice a year and saving just the masters is all that's necessary so why not. Also not a showstopper for guiding issues.

I was actually using that video but I must not have backed out correctly after setting up guiding. I can't be for sure, maybe I hit stop. I will start tonight calibrating and making sure the guiding stays active. Maybe this is why my mount starts to blink red once I hit GoTo and slew to targets as it doesn't seem to know where it is then? Good to know on exposure and temperature, I was taking 3 or even 5 seconds.


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#19 DeepSky Di

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Posted 06 October 2024 - 11:47 AM

I was actually using that video but I must not have backed out correctly after setting up guiding. I can't be for sure, maybe I hit stop. I will start tonight calibrating and making sure the guiding stays active. Maybe this is why my mount starts to blink red once I hit GoTo and slew to targets as it doesn't seem to know where it is then? Good to know on exposure and temperature, I was taking 3 or even 5 seconds.

Keep an eye on the guide chart. Also make sure the ASIAIR app is updated to 2.2.2 and the associated firmware for the ASIAIR box (11.30). 2.2.1 had horrible guiding issues. For example in my case the DEC numbers were good but the red line on the chart was off the top of the chart and the red line was correct :-(. Another time the RA and DEC would seesaw wildly. All fixed with 2.2.2.


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#20 Bob2023CL

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Posted 06 October 2024 - 11:54 AM

I also have an AM3 and had tracking issues in certain orientations. My telescope setup looks lighter than yours but it turned out I needed a counterweight. My problem starts with RA tracking ignoring the guider all the way to a complete stall. You can see pictures of my rig in my gallery.

#21 Spaceman 56

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Posted 06 October 2024 - 04:01 PM

 

My first thoughts are on the 300" subs. You can drop that to 30 or 60" for now.

totally agree.  300 seconds is madness for a beginner.

 

I will add a couple of ideas for Wednesday to consider.

 

1. shoot some 5 or 7 second subs, and try and get focus manually. its simple. you just adjust focus until the stars are as small as possible.

Don't think its not possible to focus manually. I did it for over a year and achieved some excellent images. 

 

2. only try and focus Manually when you have a very bright star is in the centre of the optics. its pointless trying to focus on a star at the very outside of the picture.

 

3. once you get close add a Bhatnov Mask and fine tune the focus even closer to perfect. you should see something like this.

 

Sirius batnov_24-2-23 LQ.jpg

 

once you get to this point you can go to the next step. (because its close )

 

4. Turn on the EAF and try an autofocus. if the step size is correct it will work just fine.

 

These are the genuine steps that all good astrophotographers Master and can do with ease if they have to.

 

Why ? because sometimes the technology does not work, and we revert to manual processes, so that we can still image and get results.

Some people want to skip all the learning, and just hit RED with an Asair and get software and an EAF to do all the thinking for them. 

 

Good Luck. Spaceman


Edited by Spaceman 56, 06 October 2024 - 04:19 PM.

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#22 Whendewsday

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Posted 06 October 2024 - 08:45 PM

Guiding losing star

 

It seems that my guiding star just slowly drops out of the green box. After a few minutes a yellow flashing box pops up saying it can't find the guide star.  

 

I notice either the RA or DEC just plummet out of the gate once I begin guiding. I think this star peak is lower than I had last night, maybe that was 700ish, but it was the same issue.

 

Edit: 

Another view of RA dropping opposed to the first image where it goes up.

IMG 0015

Edited by Whendewsday, 06 October 2024 - 08:47 PM.


#23 jml79

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Posted 06 October 2024 - 10:58 PM

I don't know anything about the ASIAir but that mount isn't even tracking and PHD is sending panic levels of corrections. Is there a setting to start the mount tracking or set the tracking rate to sidereal??



#24 Bob2023CL

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Posted 07 October 2024 - 04:22 AM

I had exactly the same problem. What you might be seeing is the mount stalling. I had to add a small counterweight to fix it. It works very well now.

#25 Whendewsday

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Posted 07 October 2024 - 06:04 AM

I had exactly the same problem. What you might be seeing is the mount stalling. I had to add a small counterweight to fix it. It works very well now.

Sorry, I missed your first reply here. Interesting, as I am trying to begin shooting just past the meridian so I don't have to worry about the flip as a newbie for now. I think I may just try something not so high and see if it's any better. 

 

 

I don't know anything about the ASIAir but that mount isn't even tracking and PHD is sending panic levels of corrections. Is there a setting to start the mount tracking or set the tracking rate to sidereal??

It does have those settings actually. I thought about using PHD2 just to get tracking going as a test. Maybe I would get more verbose logs than what I am getting out of the ASIair?




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