#I see no diference in taking more data

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kindred swallow
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i used siril and graxpert on both

marble flame
pliant solstice
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it's a game of quickly diminishing returns.... 30h vs 17h only makes for an expected factor in SNR of 1.3

kindred swallow
kindred swallow
pliant solstice
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nope signal to noise (which is really all that matters in astrophotography) scales with the square root of exposure time

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so sqrt(30/17)=1.3

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I would argue that the slight improvement is visible in your images, but given that the processing likely isn't identical (different color choice) it can be pretty hard to tell

kindred swallow
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Would you like to give it a go? I'm curious how much is there to pull out

pliant solstice
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I can try, but I am better at statistics (part of the job) than AP processing πŸ˜‰

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I'm gonna try and remember this when I'm back home and have a GPU at hand.... πŸ™ˆ

kindred swallow
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Alright, no pressure

marble flame
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@kindred swallow i did a thing

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i linearfitted the images, and extracted their L* components, and combined them in a new color image, where the L* from the 30 hrs is put in red, and the L* from 17 hrs is put in green

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and that image is part of the histogram, showing that the 30hrs is in fact less noisy, but not very much difference at all

kindred swallow
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So I need more data?

marble flame
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idk that's for you to decide

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but i just finished to identical processings of both images

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they're stretched to a point where the noise becomes much more apparent than you would make it for aesthetic purposes, but if you switch between them, you can see the difference

pliant solstice
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with a barlow the optics probably suffer and the F-ratio is really painful, I would move on to another target, but that is a very personal decision

marble flame
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i also think you may have had a problem with flats for the first part of the data

pliant solstice
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but yeah @marble flame's side-by-side is convincing, no?

marble flame
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it would both give more FOV, and increase snr to the equivalent of 2x2 binning (witch i would do to this data anyways if i were to make an aesthetic process)

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or maybe not, but i would definitely consider it

white cipher
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the raw 30 hours also is less greenish

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so in fact you should get better collors on it

white cipher
white cipher
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look at the less greens

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also 17hours one seens to have more dust spots

marble flame
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Same with the dust spots

white cipher
white cipher
marble flame
white cipher
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thats the 17 hours

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no wait a sec

kindred swallow
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My flats don't really work for some reason and the dust spots you can see there are mostly defects on my Barlow, the anti-reflection coating is crappy

marble flame
white cipher
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thats the 17 hours

kindred swallow
white cipher
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and thats the 30 hours

marble flame
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There is also some vignetting that should've been removed my flats

white cipher
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see how much i could get the less bright areas without exploding the core?

kindred swallow
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I use masks in gimp to separately controll the core and outer stuff

white cipher
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its a small diference for 15 hours of more data but plays a big role

white cipher
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no masks

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siriL and graxpert

kindred swallow
white cipher
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i had to play graxpert 2 times to get the better details

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but seens way better than the 17 hours

kindred swallow
marble flame
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I'm wondering that myself too

white cipher
kindred swallow
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My nights are 4h long and getting shorter

marble flame
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Same

white cipher
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my nights get 1 hours per night when i get a good night

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i normaly get 1 good night per week

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in a b9 zone

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so thats simply badkekw

kindred swallow
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In peak summer there is a month when the sun never goes below horizon far enough to get any astronomical night

But I'm planning on buying the minicam 8 so I should get muuuch more signal out of even those shor nights

marble flame
kindred swallow
white cipher
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me too🀣

thorn vault
# kindred swallow some time ago i got 17h on Caldwell 4 and this week I added more making it almos...

You just hit your rigs SNR limit. This happened to me too when I was first using my canon. I shot ngc 6888 for 18 hours and I didn't see a slight change. To see any improvement you have to change gear: modify your camera or buy a dedicated one; buy filters, narrowband or broadband. Shooting from less poluted skies is always gonna help.
Anyways, as someone mentioned to you earlier, SNR depends on the square of exposure time, so you get the idea, you would have to shoot for a gazillion years to see improvement.

marble flame
thorn vault
marble flame
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Yup, Ha still improving at 35 hrs

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Just have to double every time

thorn vault
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That's interesting

kindred swallow