Help understanding the sky brightness sensor option.

[bluesilver]

Hi, I am not sure what this option in SharpCap Pro is called, but under histogram, you select the brain icon / function.
This then allows you to run a sensor test to measure the sky brightness for an idea exposure time for a selected gain. ( I hope that all makes sense )

What i would like to find out please if possible is, are you suppose to slew the scope to the intended target to be imaged and then do this test?
Or are you suppose to be doing is test a different way?
This is what i have been currently doing.
I am imaging with an asi2600mc, no filters and a Skywatcher Esprit 150
For reference, i am imaging the Keyhole Nebula NGC 3372

I get a result back of 27 seconds at gain 100 and 147 seconds at gain 0, ( this was all done last night under a nearly full moon )
Any help clearing this up would be very much appreciated,
Thanks.

[admin]

Hi,

yes, it's best to run this test when already pointing at the intended target. The test measures the darkest part of the image currently in view and works out optimized camera settings for that (which will automatically be fine for the brighter parts). If you do it in a different area of the sky, it may give results that are not the right ones for your final target (for instance further from or nearer to the moon could have a big effect).

cheers,

Robin