Sky Background Calculator and Quantum Efficiency

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Topographic
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Sky Background Calculator and Quantum Efficiency

Post by Topographic » Mon Mar 30, 2020 10:39 am

Hi

I am using the ZWO ASI 183MC Pro, the only figure I have for QE is 84% (mono sensor). Do I enter this and then select the colour button?

Thanks

David

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Re: Sky Background Calculator and Quantum Efficiency

Post by admin » Mon Mar 30, 2020 6:25 pm

Hi,

Yes, by selecting the colour option you're effectively allowing for the fact that each colour filter lets through a bit less than one third of the light available. The underlying QE is unchanged, although you do have to remember that the 84% value as a peak value at a particular wavelength and the average across the whole of the visible spectrum will be smaller.

Cheers, Robin

Topographic
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Location: Pays de Serres en Quercy

Re: Sky Background Calculator and Quantum Efficiency

Post by Topographic » Mon Mar 30, 2020 6:41 pm

Robin

I assumed a lower than 'peak' efficiency (-10%).

thanks

Daid

stephen2615
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Re: Sky Background Calculator and Quantum Efficiency

Post by stephen2615 » Thu May 21, 2020 2:12 am

Hi Robin,

I was wondering about what impact the moon has on the sky background calculator. Surely a full moon would have a significant impact on the calculations. I have a cousin who lives in a the darkest skies area I know and I try to take advantage of this location compared to my Bortle 5 skies. The full moon completely changes what I can see so this suggest the calculator should be adjusted for the moon.

regards

Stephen

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Re: Sky Background Calculator and Quantum Efficiency

Post by admin » Thu May 21, 2020 6:37 pm

Hi,

Yes, definitely. The full moon in the sky near to the target that you are trying to image is equivalent to some pretty significant light pollution. The online calculator really only give some guidance – to do this properly it's best to use the smart histogram functionality in SharpCap to actually measure the background brightness level.

Cheers, Robin

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Re: Sky Background Calculator and Quantum Efficiency

Post by stephen2615 » Sat May 23, 2020 1:48 am

Hi Robin

Thanks for the response.

I will have a look at the smart histogram functionality. I have so much going on in setting up the process I almost need a checklist. I am trying to get a good spreadsheet together to give me ideal exposure times.

Regards

Stephen

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