Optimal Exposure and Noise Calculator

[Jasem Mutlaq]

Hello Joseph,

This would be an *outstanding* feature to add to KStars! Thank you for
working on it. It would require an interface and also proper
integration with the rest of KStars & INDI infrastructure, for example, the
filters used..etc.

Would this be better suited for FITS Viewer integration?

SQM & F-Ratios can be retrieved from INDI/Ekos, we probably need to add a
field for the filter band-pass in the equipment manager.

Do you have a development environment ready as per the instructions in
KStars Gitlab? https://invent.kde.org/education/kstars

--
Best Regards,
Jasem Mutlaq



On Fri, Mar 3, 2023 at 8:16 PM joseph.mcgee at sbcglobal.net <
joseph.mcgee at sbcglobal.net> wrote:

> Hi All,
>
> I'm a retired software developer (mostly Java, C, and some C++).  I've
> been using KStars on a Raspberry Pi (Ubuntu), since I got interested in AP,
> (around 2020).  Back in late 2021 I wrote an optimal exposure time
> calculator (in Java), based on the work of Dr Glover.  I just got to
> thinking that it might be a nice addition to KStars, and today I found a
> request for it:
> https://indilib.org/forum/wish-list/5300-exposure-calulator.html?start=12
>
> My current code is pretty simple but has no user interface.  It uses a few
> classes for configuration, a table of sensor gain to read noise,
> observation site location SQM value, optics F ratio data, and
> (experimentally) a filter bandpass table.  The code just iterates through
> all the combinations of the inputs to output tab delimited data to the
> console, that I copy into a spreadsheet.
>
> Keep in mind that the exposure time calculations are optimal (per Dr
> Glover), but not necessarily practical.  I've seen a slow optic, with a
> filter, in very dark skies,  produce a optimal sub exposure time
> calculation that exceeded 3 hours.
>
> If this were integrated into KStars, we would obviously need to provide a
> means for a user to input some of their own configuration information.
>
> Please let me know if you'd like to consider integrating this into KStars,
> (I would need coaching/help if I were to take this on).
>
> Example output:
>
> I have my code configured for the read noise for my main imaging camera,
> (a ZWO ASI-071 Color), SQM data for four observation sites.  F ratios for
> four optics, and bandpass info for two filters.  And I'm using an allowable
> noise increase of 5%.
>
> A small section of the output provides this information for a given site,
> optic, and sensor gain selection:
>
>
>
>
>
> *Site Name:*
>
> Chuchupate
>
>
> *Sky Quality:*
>
> 21.65
>
> magnitude per arc-second2
>
> *Light Pollution Base Rate:*
>
> 19.6
>
> e per second
>
>
>
>
>
>
> *Optic Name:*
>
> Esprit 100
>
>
> *Light Pollution Rate:*
>
> 0.65
>
> e per second for f/5.5 optic
>
>
>
> *Camera Sensor Gain:*
>
> 50
>
> *Read Noise:*
>
> 2.78
>
>
>
> *Filter*
>
> *Optimal Sub-exposure (sec)*
>
> *Shot pollution electrons*
>
> *Exposure shot noise*
>
> *Exposure total noise*
>
> No Filter
>
> 349.1
>
> 226.2
>
> 15
>
> 15.3
>
> Optolong l-Pro
>
> 634.8
>
> 411.3
>
> 20.3
>
> 20.5
>
> Optolong l-Enhance
>
> 3174
>
> 2056.3
>
> 45.3
>
> 45.4
>
> And accumulated data for imaging sessions of 1 to 5 hours:
>
>
>
> *3,600.00 seconds*
>
> *7,200.00 seconds*
>
> *10,800.00 seconds*
>
> *14,400.00 seconds*
>
> *18,000.00 seconds*
>
> *Filter*
>
> *Exposure Count*
>
> *Stack Total Time*
>
> *Stack total noise*
>
> *Exposure Count*
>
> *Stack Total Time*
>
> *Stack total noise*
>
> *Exposure Count*
>
> *Stack Total Time*
>
> *Stack total noise*
>
> *Exposure Count*
>
> *Stack Total Time*
>
> *Stack total noise*
>
> *Exposure Count*
>
> *Stack Total Time*
>
> *Stack total noise*
>
> No Filter
>
> 10
>
> 3491.44
>
> 48.37
>
> 21
>
> 7332.03
>
> 70.09
>
> 31
>
> 10823.47
>
> 85.16
>
> 41
>
> 14314.92
>
> 97.93
>
> 52
>
> 18155.51
>
> 110.29
>
> Optolong l-Pro
>
> 6
>
> 3808.85
>
> 50.14
>
> 11
>
> 6982.89
>
> 67.89
>
> 17
>
> 10791.73
>
> 84.4
>
> 23
>
> 14600.58
>
> 98.17
>
> 28
>
> 17774.62
>
> 108.31
>
> Optolong l-Enhance
>
> 1
>
> 3174.04
>
> 45.43
>
> 2
>
> 6348.08
>
> 64.25
>
> 3
>
> 9522.12
>
> 78.69
>
> 5
>
> 15870.2
>
> 101.59
>
> 6
>
> 19044.24
>
> 111.29
>
>
>
>
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