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There are so few clear nights that I have resorted to shooting my latest target (M106) through whispy clouds. I'm just about managing 0.6 to 0.7 arc secs guiding most of the time, but the subs do look washed out and a bit fuzzy. My question is: is it worth it or will it ultimately make my final image worse? My logic for doing it is that I'll get more integration time and the averaging algorithms should sort out the noise and fuzz ... am I right or am I kidding myself/wasting time? |
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7.46
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| My rule is that with hazy skies it ain't worth it, especially now with no astronomical night. You still get data I gather but a lot of effort with little return. If the seeing is also crap just give up. |
6.77
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Probably not worth it. Perhaps only when doing something like Pleiades or similar target, to create a softer and more dreamy image.. maybe?... there are more "artistic" approaches where it could work. But, I wouldn't use it to ad to "proper" data of a target that you're working on. So it's probably better to wait for a proper clear night. |
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6.89
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The problem is even thin clouds are not uniform. They are filaments that move. Not really that much different from fat, clearly defined clouds in terms of the patterns drawn on the image, except they are e.g. 5% white instead of 100% white so they do not kill the subject completely, it is true that some of it gets captured. Generally they are not worth it, except in marginal cases: let's say your composition has very low SNR at the lower left corner because your camera was moved between night 1 (20 subs) and night 2 (200 subs). So the lower left corner stands out (more grainy, different background) despite the integration's best efforts to normalize things. If the weather won't help you and the target is going away, it is probably okay to take another 100 subs through the mild clouds, do some serious background removal to the result and then take just the part corresponding to your low SNR corner and stitch it to the main composition. But the high SNR part of the composition no, it won't benefit from integrating extra cloudy data there. The cloudy data will either be rejected (if it is too few subs) or actively worsen your result. |
7.75
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I wonder whether bright targets like double stars - where in contrast to DSOs faint details are not important - are still doable with reasonable results. Clear skies Wolfgang |
4.72
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| Every now and then I talk myself into imaging during high/thin clouds, and the next day I always regret it. Guiding is bad, data is bad, and I could've spent time doing something else (like sleeping). At this point unless I'm 95% sure it's worth setting up to image, I don't. This Spring was rough for me as well...2 straight months of clouds and basically missed out on Galaxy Season. This is definitely a hobby of patience. |
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11.01
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OK, I have mixed feelings about my attempts with high/thin clouds last night. The first hour was a total wash-out: guiding was >1 arc sec and the image captures were washed out and fuzzy. Thankfully the clouds did clear pretty much for the next 1.5 hours: Guiding dropped to 0.55 arc secs RMS and I got some good subs (BTW: that's about the best guiding I've had with my HEQ5 Pro so far. It's at its limits with my 12Kg payload and 15Kg counterweights). Biggest benefit was, however, that I got to check out my re-collimation of my Newt. I try not to fiddle with the collimation very often (maybe only every 3 months or so), but it was definitely overdue and worth it. |
2.81
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| Because I only have a couple of hours viewing/imaging angle between the trees to the east and neighbor's house to the west, all of my targets require multi-night integrations. Definitely not worth polluting my good data with cloudy data. Will worsen the final result every time. I'd much rather sleep and get good data the next clear night. |
0.00
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If you’re lucky enough to have a rig that can go from off to imaging smoothly in 5-10 minutes, and happily leave it imaging all night whilst you sleep, then what’s to lose? Just time and effort trashing the worst subs when you come around to blink/subframe selector (or equivalent). If you live in a country where clear nights are few and far between and have a setup like above then I’d say worth it. Otherwise you’ll be waiting months before you can finish an image. |
1.81
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| I tried this last year on two nights, the subs didn’t look too bad but cameras these days are very sensitive ☺️ When it came to processing it was a waste of time so I’ve learnt my lesson, don’t bother unless the high cloud is intermittent. |
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2.81
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Andy Wray: The way to answer this question is to do two stacks. One with the cloud affected images included and one without them. Compare the two stacks for things like SNR, FWHM, star roundness etc. Then you can make an informed judgement as to whether or not you are wasting time taking the thin cloud images. |
18.84
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Hi all, my experience is a bit different. I even shoot with thin high clouds. But it depends on the target an whether I want to take Lum or RGB. For RGB I can take some clouds without problem. But in these case I do not guide, since guiding makes things worse when seeing is bad. Here an example from M82, where almost frame where shot through clouds. https://www.astrobin.com/3cxvjp/ On revision B you even can see the clouds passing by on the surveillance camera. So my conclusion is: it depends! Filter, target and reserves have to be taken into consideration. But there is no doubt that quality degrades and there will be Bus more subs to dump. But as the OP pointed out: there are very few really clear nights. In my location at max ten a year. So the decision not to shoot if there a faint clouds is an academic question for me. I have little to no choice - i have to take what I get. Rüdiger |
4.82
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Nope, I can not think of when this ever resulted in anything but frustration. I used to image on nights that are cloudy, any frames with a low score I delete. Even then it is hard as sometimes they are so wispy that you get a decent quality, but in the end it makes it look washed out or muddled. I simply say no to clouds. I understand the desire, I live in FL and it seems that every night is cloudy. |
10.10
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If you can leave the telescope alone outside, collecting photons without control, it can definitely be worth the effort. Drifting clouds and haze can be sorted out, but for sure, disappointments are queuing up, especially during the darkest and longest winter nights. One night last winter I did just that, and of 150 subs I got 9 good ones🥲, but a subframe is a subframe🕺. Usually I get from 60 to 120 good subs. |
9.03
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| Guys, what I do is shoot away since near San Francisco I will be waiting a looong time for perfectly clear skys. BUT, I use subframe selector to eliminate the trash. I can pick up a few good frames as the clouds move. I find that with my new CMOS ASI 6200 my frames are much shorter than my old CCD so I am many more and can be choosy. |
