ASI178 -Lunt Images w SC bu not ASIair pro

[stbkaiser]

Hi All
I know this is not really a SC issue but just wondering.
Experimenting with imaging setups for the upcoming eclipse.
Using my Lunt DBL stack with ASI178 mm camera.
I can Image the sun / surface details, with plenty of exposure latitude with Sharpcap , 0 gain, 8ms up to 15 ms
But When I try to use my ASIair pro at 0 gain, 0.001 exp
I cannot "see" the surface details, in other words it is still over exposed..
Am I wrong 0.001 = 1 ms.
With SC I have to raise my gain from 0 to see the sun at 1ms.
Any idea why the big difference.?
I can only assume AIRAIR pro is not really imaging at 0.001 s..?
Thanks for any input.
Weather is looking better for Eclipse TX . High thin clouds now showing on astrospheric.
Take care

[admin]

Hi,

you are quite correct - 0.001s is 1ms, so that should be a short enough exposure.

I can think of 3 reasons that might be causing this

1) ASI Air is not going all the way down to 1ms exposure - you can check by taking the exposure down in steps and making sure the image gets darker with every step (at some point, raise the gain, or use more light to make it bright enough to see)
2) The same, but not really going down to zero gain. The same trick of reducing gain and making sure each step makes the image darker should check that
You should be able to test 1&2 without needing clear sky - just arrange to get some light on the camera somehow.

3) ASI Air is by default stretching the image (perhaps because that is good for deep sky), which is making it look overexposed when it really isn't. Of course if the saved images also look overexposed then this explanation is unlikely.

Hopefully that will give you something to go on. I do hope that the weather turns out reasonable for the eclipse - the August 1999 eclipse here in the UK was badly hit by cloud

cheers,

Robin

[stbkaiser]

Thanks Robin
I did investigate more .
Strangely , the ASIAIR displayed image improved (somewhat) when I changed to video mode , then back to preview mode.
But I never did store any images to see what is really happening.
I will work this issue later , I think, rather than risk issues during eclipse.
At this time Astrospheric is predicting a close race for clouds appearing in the zone I will be in.
May be high clouds during most of eclipse , then who knows.
Will be keeping close eye on predictions tomorrow afternoon.
Good luck to all.
We will need it.

[admin]

Yes, good luck for tomorrow and the weather!

cheers,

Robin