Optimal exposure calculator

[Damian Mlakar]

I have Altair Astro hypercam 294c pro tec, with sharpcap sensor analise result. Seem that optimal exposure not use HCG-LCG control, becouse i get wrong readings from: example i put 200 gain (with HCG ON in camera settings) is same as 900 gain in sharpcap sensor analise results. But optimal exposure calculator usunig result of gain 200 from sharpcap (not correct ) . If i write down gain 900, then i get out sharpcap results correct in calculator, but for use calculate with 900gain in use with HCG ON give it 4,5x more, is wrong. Or am i missing something here?

For now i just first write down gain 900, (to pull out correct sensor readings), and after write down again gain 200 (with HCG ON) to use for calculate. Quite disturbing must say. Can be possible that added some function that can use HCG LCG option in optimal exposure calculator? I think if someone not see this issue, can get strange results with calculator. Specialy if someone use many different gains, need extra calculator for sorting and get results correct

[Stefan B]

https://nighttime-imaging.eu/docs/develop/site/troubleshooting/altair_dualgain/

[Stefan B]

The implementation in Sharpcap is automatically toggling the gain. Inside N.I.N.A. the choice is however given to the user how to control the gain value - which is also how the Camera Vendor SDK is designed. As there is no way to know the gain multiplier from the code perspective, designing it like sharpcap would be a constant manual maintenance effort for new cameras. Please refer to the documentation showing a more in-depth explanation about how to translate the gains.

[Damian Mlakar]

Thank you for fast respond. I know that sharpcap automatically toggling the gain and N.I.N.A is not . I was thinking if there is possible to added some option that user can manualy put multiplier that can be use when HCG is ON , becouse is quite hard to figure out if NINA actualy is using it or not. Just a suggestion.
Best regards

[Dale Ghent]

It is possible to know the operating mode as the LCG/HCG switch for ToupTek-based cameras is on the Equipment > Camera screen. In the future we may change this control to be a readout mode of the camera instead of the individual switch.

[Stefan B]

Dale, the toggle is not the problem here but rather the statistics of these compared to sharpcap. 100 gain with HCG enabled can be 200,400,800 or something else in sharpcap depending on the multiplier that is camera model specific

[Damian Mlakar]

Dale. Isnt problem here toggle, hcg - lcg. Problem was for me until i see, that optimal exp. calculator take my camera setting gain (201) and use sharpcap statistic reading 201 gain too. This is ok.

But becouse i have HCG ON in camera settings, my camera actual gain is 201x4.45….that will be similar +- 900 in sharpcap.

Oec take 201 gain (=201 LCG) from sharpcap statistic but actualy need take out gain 900. Becouse hcg is on.

So my solution was…..write down 900 gain(so call out sharpcap correct numbers), and write down 201 gain back and use calculator.

Only saying if user doesnt know this, it take wrong statistic for optimal exposure. Quite complicated.

Best regards

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[Dale Ghent]

Yes, I understand now. It’s unfortunate that SharpCap has deviated from the way that ToupTek presents the gain ranges and domains of their camera. But since the multipliers that Robin decided to use are not published, there is no feasible way for us to match these numbers, especially considering these seem to be model-specific. The native driver in NINA operates as the ToupTek ASCOM driver does - selection of the gain domain and each domain has its own range, 0 to whatever.

[Stefan B]

Removing version: 2.0 Beta (automated comment)