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ASI1600 and offset

Posted: Fri May 18, 2018 6:07 am
by dts350z
I don't see an offset adjustment in the ASI1600 camera controls. v3.1.5181 pro, native ZWO driver.

Does that mean that offset will not be adjusted/taken into account in "the brain"?

Re: ASI1600 and offset

Posted: Fri May 18, 2018 6:12 am
by admin
The offset control on ZWO cameras used to be called 'brightness' - I have heard some talk that it was being disabled on certain models of camera, but I can't recall I noticed myself whether it was there or not when testing the new SDK.

If the brightness control is there then the brain will use it. If it isn't there but the sensor analysis data was done when the control was available then the results might be weird (certainly not something I planned for!). If the brightness has gone then I would suggest re-running sensor analysis and then the brain should work fine as it is capable of working with cameras with no offset control.

cheers,

Robin

Re: ASI1600 and offset

Posted: Fri May 18, 2018 6:28 am
by dts350z
It's there in ASCOM, but only in the ASCOM "show" dialog.

Would that work with the brain?

Re: ASI1600 and offset

Posted: Fri May 18, 2018 6:23 pm
by admin
Hi,

no, sorry, SharpCap can't affect stuff in the ASCOM properties dialog without the user manually showing the dialog and adjusting the controls.

cheers,

Robin

Re: ASI1600 and offset

Posted: Sun May 20, 2018 5:12 pm
by dts350z
Downloaded and installed the latest ZWO driver.

No offset in SharpCap shown, however, in Sequence Generator Pro it is there in their camera settings and per event settings?

Re: ASI1600 and offset

Posted: Sun May 20, 2018 8:21 pm
by admin
Hi,

so my take on this is that the ZWO ASCOM driver you have installed (and that SGP is using) is utilizing an older version of the ZWO SDK that still had offset.

I have the 1600MM-Cool (not Pro) and I still see the 'brightness' control (which is offset for ZWO cameras) in the latest version (see below).

Robin
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Re: ASI1600 and offset

Posted: Sun May 20, 2018 10:04 pm
by dts350z
OK, I see "Brightness" in the Image controls (vs. camera controls). Thanks for clarifying that.

So back to Sensor Analysis, Smart Histogram, and Brain. In the Brain Results section I see Optimal gain but nothing about "Brightness" or offset, and when I hit apply, the gain changes but the Brightness does not.

?

Re: ASI1600 and offset

Posted: Mon May 21, 2018 1:36 pm
by admin
Sorry, that's just inconsistent terminology in the brain dialog, which refers to this setting as 'black level'.

Unfortunately different camera manufacturers describe this as variously

* brightness
* offset
* black level

so it's hard for SharpCap to be consistent with all manufacturers.

Except for very high gains, SharpCap will usually end up setting this to zero - that's because SharpCap takes into account the effect of sky brightness in moving the histogram away from the LHS - usually sky brightness is quite sufficient for this and no additional boost is required.

Robin

Re: ASI1600 and offset

Posted: Mon May 21, 2018 1:54 pm
by turfpit
The camera setting that is used to pull the histogram away from the left hand side

Different names for the same thing:

Altair calls it Black Level

ZWO calls it Brightness

QHY calls it Brightness

Other manufacturers may call it Offset

The Nebulosity manual refers to it as Offset

When I am writing documentation I would use Offset/Brightness/Black Level

It is a good job there are standards or this would all be very confusing :lol:

Dave