Is this a camera/filter problem or my own processing problem

ZWO ASI294MC Pro CMOS Processing Deep Sky Artifacts
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mousta avatar
mousta avatar
Folks, 

I have an ASI294MC Pro using it with a Celestron Edge HD8.  I have been having terrible problems with strange artifacts in my images (weird circles, strange gradients).  I think the gradients might be due to me not using flats. Im working on adding them - but the part that is super annoying is the strange circles. Any ideas what that is ? I can't remove them at all - I have used Darks and Bias frames.
chefjedidiah avatar
chefjedidiah avatar
dust
NighttimeskyGuy avatar
NighttimeskyGuy avatar
Take and use flats, you have classic dust donuts and light gradients. You will be amazed how good your stack will look after doing proper calibration !
Best of luck and be sure to show us the one afterwards. 
CS
Helpful Concise Engaging Supportive
Mitch123 avatar
Mitch123 avatar
Clean your camera sensor window before you start a new target.  That will keep the dust to a minimum. Take flats for each filter at the end of the night to remove the rest.
Well written Concise
FiZzZ avatar
FiZzZ avatar
Also to have such “flattened” image says that probably light conditions and exposure do not cope super well…
the pic was taken at astronomical darkness time or before/after ?
or under full moon ?
or it was cloudy ?

Definitely , take flats and calibrate the shots will give a huge improvement smile
resist the temptation to clean the optics (how old is your telescope?) as however dust, pollens, insects and so will come back soon…
mousta avatar
mousta avatar
Thank you All - I will go ahead with the flats tonight and share the results. I dont see this much dust particles 
Take and use flats, you have classic dust donuts and light gradients. You will be amazed how good your stack will look after doing proper calibration !
Best of luck and be sure to show us the one afterwards. 
CS


Thank you - I didnt really see that many dust particles   I guess I cant see them well. Glad to know its not something super bad. I will try with the flats tonight and will make sure to show the result after.
mousta avatar
mousta avatar
Also to have such “flattened” image says that probably light conditions and exposure do not cope super well...
the pic was taken at astronomical darkness time or before/after ?
or under full moon ?
or it was cloudy ?

Definitely , take flats and calibrate the shots will give a huge improvement
resist the temptation to clean the optics (how old is your telescope?) as however dust, pollens, insects and so will come back soon...


Yeah this was under full moon almost three days ago - it was def. after astronomical darkness.  I was super worried it was something bad. I will try the flats and see - Didnt really realize flats will help dust particles. 
Appreciate your advice to resist the temptation to clean the OTA  - I was getting to do this once I saw the responses that it is for sure dust ha!!
Jérémie avatar
Jérémie avatar
Thank you - I didnt really see that many dust particles   I guess I cant see them well.


Indeed, usually your lens or filter looks clean, but in the end you have dusts :-)
When the donut shape is small, it means the dust is closer to the sensor (maybe the case here), so if you have to clean or blow air (not using an air bomb that may contain oils, but a manual dust blower), start by what is right before the sensor, or maybe the sensor itself using specialized tools if that a DSLR (if that’s astro camera, usually you have a window in front of the sensor that protects it.
For filters, when required, I use isopropanol.

Most of the time, just blowing air with a manual dust blower on all optical parts before starting shooting limits those donuts (unfortunately I can’t leave my setup mounted, as I don’t have a fixed home-observatory, and I have to manipulate it frequently, so it is necessary...)

https://www.thedustpatrol.com

https://www.digit-photo.com/GIOTTOS-Poire-Soufflante-rGIOTTOSD44140.html
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mousta avatar
mousta avatar
Thanks everyone for your help! I took the flat frames this morning - And Yup - I couldnt believe how much difference it makes. I still have work to do on color balancing! but boy all the weird gradients and the dust donuts are basically gone
https://photos.app.goo.gl/YMM1e8kYWRVDFHTi9
mousta avatar
mousta avatar
Updated picture
Patrick Graham avatar
Patrick Graham avatar
Moustafa,   Check out my thread "Cleaning Optics" under the "Equipment" subject header in the forum home section.   Lots of great advice and techniques from experts here on how to properly clean and remove dust and smears from your lenses and filters.   Also,  I have found, through trial and mostly error,  that flat frames are essential in producing quality images as we can never completely remove all dust and imperfections from our optics.  Lots of instructional videos and tutorials on how to take flat frames.  It's a little labor intensive but well worth the effort.

Clear skies,

Patrick G
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Jerry Yesavage avatar
Jerry Yesavage avatar
Need flats buddy.. will always be dust around.  Lots of image acquision software does it….
Peter Bresler avatar
Peter Bresler avatar
Those dust motes show up when you shoot under the full moon.
Well written
urban.astronomer avatar
urban.astronomer avatar
The sharper the objects look, the closer to the sensor they are. I guess these dust moths are located on the glas plate directly in front of the sensor. If you apply a strong light source, you will suddenly be able to see them also.
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