Functionality of flat panel and Flat Wizard

[Timothy Hutchison]

I am new to NINA, so please forgive any new user mistakes or misconceptions. However, I believe there is an issue with using the Flat Wizard with a flat panel.

I am currently using a USB controlled flat panel from Artesky. I can connect to the panel and can manually control the brightness.

With my current astrophotography tool, I manually (SGP) or automatically (Voyager) determine the flat panel brightness that corresponds to taking a 5 second flat exposure for each filter/bin. So, for example, it may look something like this:

L: 1x1: 28%
R: 1x1: 41%
G: 1x1: 32%
B: 1x1: 29%
Ha: 1x1: 60%
Oiii: 1x1: 45%
Sii: 1x1: 55%

(These numbers are not actual, just representative of goal). The way I generate this in SGP is manually. I keep adjusting the brightness panel and take a 5 second exposure, looking for an exposure at the middle of the range, and repeat for each filter/bin. Voyager does the same automatically. I simply set the min and max exposure to 5s and it automatically finds the appropriate panel brightness setting. I then record (manually for SGP, automatically for Voyager) the brightness setting and 5s exposure time for flats for each filter and bin level. When I take flats, the sequencer sets the brightness of the panel based on the recorded values for each filter/bin before starting the exposures.

The reason to do it this way is that I only need to have 1 set of flat darks, 5s in duration, to be used with the flats for each filter.

I tried to accomplish the same task with NINA. Setting the Flat Wizard to 5s for min and max exposure did not work. NINA started with the panel brightness at 100%. Too bright try again. It lowered it to something less (I can’t remember exactly what), lets say 50%. Took an exposure. Too bright, try again. It again lowered it to something less, say 20%. It then came up with an error message that said the light source was too faint, increase the light source and start over (I’m paraphrasing). What it should have done in my opinion would be to increase slightly and keep cycling until it found an acceptable ADU value for a 5 second exposure.

No big deal…I’ll try manually just like with SGP. However, once I determine the appropriate values, I cannot see how I can manually enter the brightness levels for each bin/filter combination.

I believe the behavior of the Flat Wizard is incorrect. I could simply do it manually with the additional feature of being able to manually edit/enter the values.

Thank you!

[Timothy Hutchison]

Additionally, the flat panel control only allows a percentage input. The panel has values from 0 - 255 in all other applications. Each percentage point is then 2.5. The issue is that:

1. You cannot tell if you will get 2 or 3.
2. I cannot set a value of +/- 1 unit.

I know this sounds small, but with this flat device and camera 1 unit is 4000 ADU’s, which is more than 10% of the median value of ~32k.

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[Stefan B]

Flat wizard can now specify a specific panel brightness to find an exposure time for.

In a future release this might also be able to be reversed that the exposure time is fixed and a panel brightness can be found.

[Timothy Hutchison]

Stefan:

I appreciate that you have taken the time to look into this issue, but your change has done nothing to address the issue. The issue is that you should be able to adjust the panel on a per filter basis to allow for a single exposure time for flats across all filters. This allows for a single use of flat darks to be used rather than having a separate set of flat darks for each filter. Without that ability we are unable to use the panel for the purpose it was intended.

As I said in the original posting, a much more simple solution would be to allow for the manual editing of the brightness settings and exposure times for each filter.

Again, thank you for listening.

Tim.

[Stefan B]

The flat wizard currently is designed to find exposure times. As i said in a future version this might be changed to allow for fixed exposure time and finding the correct birghtness instead.

As for manual editing the trained values to be used inside a sequence, there is an open pull request, which i will review soon.