How to maximize the exposure time during full moon without errors?

[roywspencer-nsstc]

I'm using my RPi build partly to find nice meteors. I missed a really big one captured by local video cameras because during the full moon the exposure time was 1.6 seconds on a 15 second duty cycle using auto exposure, so the bolide occurred in between exposures. I've tried using manual exposure, but during a bright moon I get "bad image" errors, I assume due to some limit on brightness of the images. How do I use manual exposures to get useful images that might produce saturation of the image around the moon, but still allow me to get (for example) a 15 sec exposure every 17 seconds (with dump time)? If I can do it with my DSLR camera, it seems like I should be able to do it with my ASI676MC camera.

[Alex-developer]

What do you have Remove "Bad Images Threshold High" set to?

[roywspencer-nsstc]

Thanks for replying. I couldn't find what menu that is under. Where is it?

[roywspencer-nsstc]

oh, I did find it before... it's been set to "0" so those checks are disabled.

[Alex-developer]

Can you set the debug level to 4 then let Allsky run so that it discards some of the frames. Once thats done post hte support log info and I'll see fi I can see why they are being discarded

[roywspencer-nsstc]

I increased my exposure time from 12-15 seconds to 30 seconds, and reduced the gain from ~250 to 100, and now everything is working fine in manual exposure mode.

[Alex-developer]

Glad you got it working

[EricClaeys]

@roywspencer-nsstc,

The ZWO auto-exposure algorithm looks at just part of the image to determine what exposure to use. That part is centered on the sensor and is 500 x 500 pixels by default. Look in the "Both daytime and nighttime" section of the WebUI Settings for this:

I use 500 500 60 70 on my Pi so the Sun and Moon don't go through the histogram box.
If you temporarily change the "Overlay Type" to "legacy" you can then display the histogram box to help you determine what numbers to use.

[roywspencer-nsstc]

Hi Eric:
Thanks for the suggestion, I had already figured that solution out and moved the histogram box to an area where neither the sun nor moon will pass through it. I'm still trying to optimize the gain and exposure time settings... I asked Grok, which did a thorough analysis of the ZWO ASI676MC camera sensor and said the optimum was 30 sec with a gain of 180. So far that's working well. Still need to play with the setting that controls exposure change jumps to smooth out the timelapse. But overall I'm pleased with the results, and even got timelapse of the aurora here in N. Alabama... third time this year it's reached this far south, and I really didn't expect to capture it with my new Allsky system since I figured it wouldn't happen here again.
-Roy

[EricClaeys]

@roywspencer-nsstc,
If everything is working would you please close this Discussion?
Thanks - Eric