Hey Guys! Need some help - I purchased my self an asi air plus. Everything is working great - guiding, polar alignment etc! I did a few test shots and noticed there are black streaks on the screen. It ruined my whole imaging session.
2 nights ago I used my laptop and sharpcap and it was fine! I cant see any dust specs. Its only when plugged into the asi air and capturing.
I was using the internal mmc of the asiair to save my captured photos.
I thought stacking flats and darks might fix it but nope!
Ive checked the sensor and the lens for dust but it all looks fine!
Any Ideas?
Gear:
Redcat 51
ZWO ASI533mc PRO
Here's 40 min worth of lagoon and trifid to give you an idea of what I'm talking about.
too dark to see anything what are we supposed to be looking for? can you stretch the image so we can have a better look?
From brightening my screen to max it looks like dirt streaks on the imaging train. Never experienced an issue with the asiair like that. Seems like one bad image may be causing the weird artefacts, check all you images first to see if one is out badly.
My first thought when I looked at the image was that the streaks are all the same in length, shape and direction. They look like dust donuts that have slowly shifted across your image during the run. That to me screams out bad polar alignment, but you said your polar alignment was great so I'm at a loss.
Are you absolutely sure the polar alignment is good? Comparing the first sub and the last sub, did the stars shift a lot between the two?
I used the inbuild polar alignment with asi air plus and I even did it 3 times. I was so close to perfect according to that. when i slewed to my target it was bang on centre. I'm assuming my polar alignment was perfect. I usually use the synscan controller. Ive stretched the image to really show how many marks their are.
bare in mind when using sharp cap and my laptop to take exposures i have zero issues.
Last edited by Fluffyllama95; 10-08-2022 at 11:49 AM.
Ah, OK. I have no experience with the Asiair plus or its polar alignment routine.
The other possibility is something flexing or moving during the run. As a mater of interest, can you post your first and last sub?
I would check through all of your individual subs. AlASIAIR live stacking doesn’t do a very good job at eliminating poor subs so sometimes it tries to integrate these into the final stack and can cause big problems like this
Well you can definitely see them there too… mate that’s a head scratcher!!
And I’m assuming the marks don’t show up on your flats as well? Maybe post your flat frame here too if you have it…
Not sure if this helps, but I had donuts not smudges on my images last week. These did not show up on flats, only on my lights. It was dust on the sensor of the camera, a good clean fixed it up. I also could see nothing visually, it does not take much at all to make a huge imprint on your results.
A stretch of your flat frame reveals a few dust bunnies. That's not a problem, except for the fact that I can see these corresponding dust bunnies overcorrected in your stretched image in post #6. This tells me that your flat maybe isn't calibrating correctly - possibly due to your flat being too bright? I'm not familiar with your camera or ota so someone else may be able to give some more specific advice.
If it were me, I'd just start from scratch the next clear night (clean everything again, new calibrations and data) and see if it gives the same issue again.
Not sure if this helps, but I had donuts not smudges on my images last week. These did not show up on flats, only on my lights. It was dust on the sensor of the camera, a good clean fixed it up. I also could see nothing visually, it does not take much at all to make a huge imprint on your results.
Trying to image through high cloud or fog will do that! The illumination is different in those frames so the dust bunnies are more pronounced and will show in your calibrated stack.
I have had similar things. Usually getting too close to the moon when it is fairly bright. Looking on Sky Safari, that would appear to be the case. Not sure why this happens, but try imaging well away from the moon to see if problem persists!