Noob astrophotography

CCD vs Film? Lots of time vs no patience? Alright, this is your place to discuss all the astrophotography what's and what's not. You can discuss about techniques, accessories, cameras, whatever....just make sure you also post some nice photos here too!
perchloratepenguin
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Re: Noob astrophotography

Post by perchloratepenguin »

Crux, The Southern Cross. Shot on Olympus OMD EM5 with a Olympus M.Zuiko Digital 45mm F1.8. 45mm, ISO 200, 4s, f/2.2. Stacked 100 times in Siril and touched up on GIMP.
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xorinet
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Re: Noob astrophotography

Post by xorinet »

Exams are over! Expect better pictures from us in the coming June Holidays.

For now, here's my first picture of a galaxy other than the Milky Way (woohoo!)
r_seqbode_stacked-min.jpg
M81 and M82

Shot on 15/5/2022 from 8:30-10:30pm

Shot with Nikon D5500 (full spec mod) with Sigma AF ZOOM APO 70-210mm f2.8
210mm (cropped in postproc), ISO 160, shutter speed 4s, f2.8, custom white balance
1200 pics stacked with Siril in 2 groups, touched up with GIMP

I took advantage of the clear skies and took pictures until I was worried my computer wouldn't be able to stack them all. After exams, a new lens was acquired that allowed me to bump my ISO down to the below 200s, even with only a 4s exposure time. I'd say it was worth it - though the picture may be noisy (somehow even at ISO 160), the galaxies are somewhat visible. A win in my league!
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hhzhang
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Re: Noob astrophotography

Post by hhzhang »

xorinet wrote: Mon May 16, 2022 5:49 pm Exams are over! Expect better pictures from us in the coming June Holidays.

For now, here's my first picture of a galaxy other than the Milky Way (woohoo!)

r_seqbode_stacked-min.jpg
M81 and M82

Shot on 15/5/2022 from 8:30-10:30pm

Shot with Nikon D5500 (full spec mod) with Sigma AF ZOOM APO 70-210mm f2.8
210mm (cropped in postproc), ISO 160, shutter speed 4s, f2.8, custom white balance
1200 pics stacked with Siril in 2 groups, touched up with GIMP

I took advantage of the clear skies and took pictures until I was worried my computer wouldn't be able to stack them all. After exams, a new lens was acquired that allowed me to bump my ISO down to the below 200s, even with only a 4s exposure time. I'd say it was worth it - though the picture may be noisy (somehow even at ISO 160), the galaxies are somewhat visible. A win in my league!
This is a nice brutal force by a massive set of short exposures.

This pair of targets is still on my bucket list -- near the north pole and never climb above 22deg above the Singapore horizon.
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xorinet
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Re: Noob astrophotography

Post by xorinet »

Thanks! Have to make do with short exposures without a tracking mount, heh

maybe in the future, or when we finish our project :mryellow:
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joachim.ong
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Re: Noob astrophotography

Post by joachim.ong »

Always nice to see galaxies taken in sg, and pretty damn incredible without a tracker!!

ISO doesn't really make a difference because most modern cameras are pretty iso invariant, but still higher iso (higher gain) might have slightly lower read noise. Also the stretching done after stacking will negate any pre-set iso level.
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xorinet
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Re: Noob astrophotography

Post by xorinet »

joachim.ong wrote: Tue May 17, 2022 9:36 pm Always nice to see galaxies taken in sg, and pretty damn incredible without a tracker!!

ISO doesn't really make a difference because most modern cameras are pretty iso invariant, but still higher iso (higher gain) might have slightly lower read noise. Also the stretching done after stacking will negate any pre-set iso level.

Ooh, I see. Thanks!
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xorinet
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Re: Noob astrophotography

Post by xorinet »

Two things it seems I am obsessed with now: galaxies in Ursa Major, and wasting my time. Maybe I am a masochist.
r_seqpinwhl_stacked.jpg
M101

Shot on 18/5/2022 from 8:00-10:30pm

Shot with Nikon D5500 (full spec mod) with Sigma AF ZOOM APO 70-210mm f2.8
210mm (cropped in postproc), ISO 320, shutter speed 4s, f2.8, custom white balance
2000 pics stacked with Siril in 4 groups, touched up with GIMP

Yes. 2000 exposures, and it took me 2h30 to capture everything and 2 days of straight processing to process this image. These images were divided into 4 groups, stacked in each group individually, and the resultant stacked files were again stacked to get the final image. In my opinion, it was worth it; not only was I able to get good detail on M101, but other small galaxies in the region can be seen speckled around as well!
I wonder if there's a more efficient way to stack large amounts of exposures - my drive is too small to handle all the files at once. Suggestions are highly appreciated! Thanks in advance!
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perchloratepenguin
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Re: Noob astrophotography

Post by perchloratepenguin »

Omega Centauri at 400mm

f/4.0, 2 seconds, ISO1600, CWB
Stacked 300 times in Siril and edited on Gimp

This photo was taken nearly a month ago. June has been really cloudy so I didn’t get any pics :(
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xorinet
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Re: Noob astrophotography

Post by xorinet »

How ironic: when we're free for a month, there are clouds, so we don't do AP; and now when we're busy again, there are no clouds, and we've restarted AP :mryellow:

Image
Veil Nebulae

Shot on 27/6/2022 from 12am to 4am and 2/7/2022 from 12am to 2am

Shot with Nikon D5500 (full spec mod) with Sigma AF ZOOM APO 70-210mm f2.8
140mm (cropped in postproc), ISO 800, shutter speed 4s, f4, custom white balance
1300 pics stacked with Siril in 3 groups over 2 nights ((400-400), (500)), touched up with GIMP

Many new problems have arised: the first being fringing. Chromatic aberration makes red and IR light focus on a different plane than other wavelengths, and even with my APO lens, you can see the effects of this happening as a light brown halo around most of the stars. I've tried defocusing slightly to try and get the red and blue-green light to be "equally out of focus", but that hasn't helped much. I'm contemplating taking shots where red is in focus and then where blue and green are in focus, and integrating the individual channels together, but I feel like that would be a bit of a hassle.
Secondly, star reduction. GIMP really isn't the best platform for good star reduction. As you can see, I have tried reducing star size and star count in this image (using the guide here), and have failed miserably. Not in the sense that the stars are still there, but that I have removed too much. Dark patches everywhere. I don't want to spend hundreds on PixInsight, so this is what I'll have to put up with for now.

Suggestions/feedback would be appreciated, thanks :)
perchloratepenguin
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Re: Noob astrophotography

Post by perchloratepenguin »

Shot with Olympus Pen Mini EPM2 that I modified to full spectrum with Olympus M.Zuiko Digital 14-42mm f/3.5-5.6
14mm, ISO 640, Shutter speed 8s, f3.5, Custom white balance
800 pictures stacked on Siril and touched up with GIMP

The coma is quite apparent
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