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!
My second attempt at astrophotography from our Bortle 9 skies. Nothing fancy, just UV/IR filter with uncooled zwo585mc camera, sharpstar 61edph iii w reducer/flattener (FL 268mm, F3.9), iOptron cem26 (unguided). All without darks, flats etc, unprocessed other than live-stack using asiair mini.
Very nice images. I'd actually venture to guess that it's really Bortle 7 to 8 at you location rather than Bortle 9 from your images. I'd suggest that you start stacking more than 30 subs (1 hour at 30 s is 120 images, 3 hours is 360 images) and then process offline. Looking at your data, I think it's possible to get pretty good broadband results.
I'm glad that imaging for more than 3 hours a session is possible.
It is quite intuitive to practicing imagers that Bortle class do vary over our small island. (Refer rifleman175's A Method of Determining the Bortle Class at my Observation Site), i do agree with rifleman's finding that "the light pollution at Senkang is around Bortle 7.0 at altitude of 55 degrees looking South". So, there is nothing to guess but for simplicity, we just say Bortle class 9 sky to represent SG in general.
cytan299 wrote: ↑Fri May 03, 2024 7:31 pm
Hi Bernard,
Very nice images. I'd actually venture to guess that it's really Bortle 7 to 8 at you location rather than Bortle 9 from your images. I'd suggest that you start stacking more than 30 subs (1 hour at 30 s is 120 images, 3 hours is 360 images) and then process offline. Looking at your data, I think it's possible to get pretty good broadband results.
I'm glad that imaging for more than 3 hours a session is possible.
Thanks!
cytan
Thanks for the tip. Next round I will try to focus on just 1 or 2 objects with more subs for each of them
I was pretty much a visual observer all these years, so past few sessions have been sort of trial and error to see how many objects can be captured in a short observing session, ie more EAA rather than true astrophotography. Actually I’m quite blown away that with such a small scope, some of the dimmer objects can actually show up with details after just a few stacks. Other than Omega Centauri, most were just tiny grey smudges visually even with 6” or 8” scopes.
PETER LOO wrote: ↑Fri May 03, 2024 8:46 pm
It is quite intuitive to practicing imagers that Bortle class do vary over our small island. (Refer rifleman175's A Method of Determining the Bortle Class at my Observation Site), i do agree with rifleman's finding that "the light pollution at Senkang is around Bortle 7.0 at altitude of 55 degrees looking South". So, there is nothing to guess but for simplicity, we just say Bortle class 9 sky to represent SG in general.
You’re right that I sort of took it as a given that SG skies are Bortle 9 throughout the island as most of the time, only the brightest stars and planets are visible. Especially at street level, which was where I’ve been observing until recently. I never thought that astrophotography is possible in SG, until I saw some of the videos on youtube by “Cuiv the Lazy Geek”, who images from equally light polluted Tokyo. So I thought why not just give it a try?
Images of M51 and M57 taken on Thursday 9 May 2024 through Williams Optics Megrez II 80mm. Unguided subs using Zwo Asi533MC Pro cooled at 0degC. Streaks on M51 image likely due to live stacking. I did not take darks or flats.
M51: 60s x 50 live-stack, stretched using GIMP.
Stacked100_M51_30.0s.jpg
M57: 30s x 20 live-stack, stretched using GIMP.
Stacked11_M57_30.0s_x_20.jpg
Omega Centauri: 180s single-shot, no post-processing.
NGC5139-OmegaCentauri-180s-2024-05-09-crop2.jpg
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Hi Bernard,
Your images look promising for more processing. I’d suggest that you do colour balancing in GIMP to get rid of the green. It’ll look a lot better after you do this.
Thanks for the tip. Yeah, I think I also overstretched some areas like core of M51.
I gotta learn how to properly use these image processing software first. Previously I just do visual and simple EAA with no post processing. Life was much simpler then . But astrophotography can be addictive! (And costly $$$ )
Saturday was first try with GIMP and last night finally figured out how to use Siril to do image stacking without darks and flats. Next will be to learn how to take flats and bias frames, plus do the auto guiding thing .
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