Astrophotographer Captures 68 Hour-Long Exposure on a Single Target

[KingClinton]

Ok fellow forum friends, what is your longest exposure on one target?
I don't know where the guy in the linked article found quite so many clear nights!
Heck of a project!

https://www.google.com/url?sa=t&source= ... JCatT6cT4O

[Juno16]

Hey Clinton!

That's a lot of time!

All AP'ers have different circumstances to deal with. Some have to struggle to find a clear night, and set up their equipment every time and others start imaging at home on their pc while their equipment is set up in a dark site with pristine skies at a remote location.
Different strokes.
My longest is 14 hours, but I average 6-8. Sometimes I have to cut it down significantly because of the weather.
On Astrobin, it is not uncommon to see images that have integrations of a hundred hours or more!

[KingClinton]

Is there a point where there are enough hours on target and the gains are minimal and no longer adding to the image, does the camera eventually reach a point of maximum saturation?
I wonder what is gained from 100 hours plus, when are the hours on target too many?
Not sure I have worded that very well but AP and the terminology are not my thing, I hope it makes sense.

[bobharmony]

I have gone as far as 9 hours on a single target over multiple nights, I usually get between 2-3 hours on a target due to conditions here. I find that trying to combine several nights data is challenging as sky conditions vary widely from night to night (and even over a single night).

The reason for more integration time is to improve the Signal-to-Noise ratio. In identical conditions that is a simple square root ratio over time. Increasing exposure 4x produces a 2x improvement in SNR, for example.

Bob

[starfield]

Is there a point where there are enough hours on target and the gains are minimal and no longer adding to the image, does the camera eventually reach a point of maximum saturation?
I wonder what is gained from 100 hours plus, when are the hours on target too many?
Not sure I have worded that very well but AP and the terminology are not my thing, I hope it makes sense.

Hey Clinton, this is a tough one. There generally is a point of diminishing return, but a lot depends on the target. What I find as I take more and more exposures, the bright bits of your target reveal themselves first. At some point you just don't see much improvement in the bright bits. Once these bright bits look good, the finer/fainter details/details start showing up as you go longer. So for example, Orion reveals itself really quickly, but if you want to really get the detail in the fine dusty tendrils around the edges, you will need more time.

Figuring out when you have enough detail really boils down to how happy you are with the faint stuff and how much sky time you've got. As was mentioned SNR gets better the more time you've got but its not linear, so as your exposure time increases you have to run much longer for the faint stuff. For multinight targets, what I typically do is run a quick stack of the previous nights run and see how the data looks. If the background looks really noise and the target looks grainy, I'll grab more time. For narrowband work this really is important as sometimes there's a big difference between the HA and OIII signals. If there is, you usually end up taking more OIII subs than HA to get the noise down and a stronger signal.

As for my record, it's 43 hours on a narrowband target from my backyard. Being narrowband it was easier for me to work around the moon and get more time. For LRBG work, I usually drive out to the desert so that usually limits me to one or two nights. On the plus side, shooting 1 hour in the desert gives me the same quality image as shooting 6 hours from home!

CS --Steve

[yobbo89]

about 30 hrs on a 9 panel in ha is about the max done, i did do an extra 70 hrs but had a few bad panels and couldn't complete the full hso image ., i usualy do about 20 hrs for a single panel

[AstroBee]

75hrs 40min is my record on the Lobster Claw.
https://www.theskysearchers.com/viewtopic.php?t=32856

When is enough, enough? It's really about SNR. I've found that shooting narrowband from my backyard (Bortle 8-9) I need about 20-25 hours per filter before the noise is acceptable.
But if I'm shooting that same subject from a Bortle 3 location I can usually get by with about 6-10 hrs per filter.
Of course with modern AI tricks like BlurX and NoiseX, these numbers are lowering.