Output format

Discussions of Electronically Assisted Astronomy using the Live Stacking feature.
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Tiago Ferreira
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Output format

#1

Post by Tiago Ferreira »

Is there any difference in changing the output format files if i only do live stack and "save as seen" and i don't save any frames?
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12" f/5 Dobsonian GSO
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6" f/5 Dobsonian Go-To Virtuoso Gti
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admin
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Re: Output format

#2

Post by admin »

Hi,

no, since 'save as seen' is always PNG regardless of settings.

cheers,

Robin
MikeHuerto
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Re: Output format

#3

Post by MikeHuerto »

Hi Robin
As a follow -up to Tiago's question, if I am saving as '16 bit FITS file' -do I need to set the camera output format in the top right as 16 bit or FITS? I use the save '16 bits FILE' option to optimize images in other software (e.g Startools), and would like a FITS file with the highest res possible. So I would like to know the best way of doing this.


Finally, as regard the quality/resolution of the PNG file, I assume from your answer above that no increase in resolution of the PNG can be expected by by switching from 8 to 16 bit output format? Is this correct?

Thanks again for developing this software - really great stuff!

Mike
Bortle 5
Skywatcher GOTO Synscan 14" Dobson
Skywatcher 130PDS on HEQ5
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admin
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Re: Output format

#4

Post by admin »

Hi,

the save as 16 bit / save as 32 bit always save as FITS, regardless of any settings (fits is the only format to support 32 bit anyway!).

You should have your camera in 16 bit mode when live stacking (especially if your exposures are more than a couple of seconds) otherwise you will be throwing away detail near the background level. The PNG files saved through 'save with adjustments' and 'save exactly as seen' are 8 bit - any increment from changing to 16 bit (and there isn't a way to do that right now) would be minimal, since the non-linear stretch from the live stack histogram and/or the mini histogram has already been applied.

cheers,

Robin
MikeHuerto
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Re: Output format

#5

Post by MikeHuerto »

Thanks Robin
I've noticed increased /fasterperformance of live stacking in 16 bit compared to 8 bit camera output (haven't rigorously tested this, so might be my imagination)-if so, is that because the extra detail helps pick up the finer detail of faint stars?

Best
Mike
Bortle 5
Skywatcher GOTO Synscan 14" Dobson
Skywatcher 130PDS on HEQ5
ZWOASI224MC and ASI294MCPro
Laptop = Lenovo Legion 5 FullHD 144Hz (Intel Core i7-10750H, 16GB RAM, 512GB SSD, NVIDIA RTX2060-6GB, Windows 10
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Re: Output format

#6

Post by admin »

Hi Mike,

not something I've tested specifically, but star detection is often the slowest part of the live stacking process (aside from the sharpening options), so anything that helps bring out the faint details and make the stars easier to spot may help.

thanks,

Robin
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Tiago Ferreira
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Re: Output format

#7

Post by Tiago Ferreira »

admin wrote: Wed Jul 07, 2021 1:11 pm Hi Mike,

not something I've tested specifically, but star detection is often the slowest part of the live stacking process (aside from the sharpening options), so anything that helps bring out the faint details and make the stars easier to spot may help.

thanks,

Robin
So, should i try it too? Work at Raw16 even just saving as seen with no saved frames? Could it help the live stacking work?
Youtube channel: https://youtube.com/@DobsonianPower

12" f/5 Dobsonian GSO
8" f/6 Dobsonian GSO
6" f/5 Dobsonian Go-To Virtuoso Gti
Dwarf II Smart Telescope
Geoptik Eartha Eq Platform
ZWO ASI224MC + ZWO ASI294MC
User avatar
admin
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Re: Output format

#8

Post by admin »

Hi,

yes, always use high bit depth (RAW12/14/16, MONO 12/14/16) for deep sky or live stacking - otherwise the limitation to only 256 levels of brightness for RAW8/MONO8 can throw away data.

Robin
MikeHuerto
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Re: Output format

#9

Post by MikeHuerto »

Hi Robin
Above, I meant to say "I've noticed increased /faster rperformance of PLATE SOLVING (not live stacking) in 16 bit compared to 8 bit" .... but I guess its bound to help?
Mike
Bortle 5
Skywatcher GOTO Synscan 14" Dobson
Skywatcher 130PDS on HEQ5
ZWOASI224MC and ASI294MCPro
Laptop = Lenovo Legion 5 FullHD 144Hz (Intel Core i7-10750H, 16GB RAM, 512GB SSD, NVIDIA RTX2060-6GB, Windows 10
Tymaishu
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Joined: Mon Sep 06, 2021 5:13 pm

Re: Output format

#10

Post by Tymaishu »

I’ve got a question on this now because the Sharpcap users manual specifically says this.

“If having the option of choosing a higher bit depth (RAW10,12,16 or MONO16), only do so if there can be see no noise that changes from frame to frame in the corresponding 8-bit mode. If there is visible noise in 8 bit, then all that a higher bit depth will do is measure and store more detail of the noise (and make output files twice as big). This means that higher bit depths are only useful at low gains.”

Correct me please if I’m wrong but in cases where you are shooting high gain short exposures 10 sec or less in the case of EAA with an Alt Az mount like a dobsonian, wouldn’t it be better to shoot in Raw 8 if the noise level changes from frame to frame in a five minute set?
Last edited by Tymaishu on Mon Sep 06, 2021 5:26 pm, edited 3 times in total.
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