Smart Histogram optimal exposure question

[Lennyk]

Hi Folks,
Apologies if this has been asked but I couldn't find an answer. So I have an AA26C camera and I have completed sensor analysis I open up the smart histogram and it tells me that optimal exposure is for example 30 seconds at gain 200. Is this the actual time I need to shoot or do I need to multiply this value by 3 to take into account the 3 colour channels used in the Debayer process?
I may have confused myself after watching Dr. Glover's excellent video on Deep sky Astro.

Thank you for clarifying this for me.
Lenny

[admin]

Hi Lenny,

the effects of the colour filters over the pixels in the camera are taken into account by the fact that they affect the amount of light measured when doing the sky brightness measurement - that means that you need to use the figure shown, no need to increase it.

That being said, treat the figure shown as a minimum - you can go longer if your mount tracking/guiding will cope with it. Going shorter will degrade the final stacked image. Going longer will not significantly improve the final stacked image, but may be desireable for other reasons (less files created for instance)..

cheers,

Robin

[Lennyk]

Thank you Robin for the reply, I appreciate the response.

[Lennyk]

Can I ask one other question So I re-ran my sensor analysis(using a laptop monitor as a white source with a piece of paper over the screen) and I noticed my e/ADU values look really small. Is this correct or is the refresh rate of the laptop affecting these values?

[admin]

Hi,

those values are correct for that camera - the camera has a full 16 bit ADC (65536 possible ADU), but the full well electron count is only about 53000, so the maximum e/ADU is less than 1. It's the same for the 178 sensor, which has a 14 bit ADC and about 12000-14000 FWD if I remember correctly.

cheers,

Robin

[Lennyk]

Thank you again Robin! and thank you for creating a fantastic piece of SW it truly is remarkable!