Author Topic: Interpreting BasicCCDParameters Script Report from OSC Camera  (Read 175 times)

Offline poochpa

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For an OSC camera, what do the columns represent in the report below from the BasicCCDParameters script? For example, there are different RN and gain numbers in each of four columns, so which one should I use?  Data is from a ZWO ASI071MC-P camera. Thanks.
Mike

Offline sharkmelley

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Re: Interpreting BasicCCDParameters Script Report from OSC Camera
« Reply #1 on: 2020 January 15 09:58:27 »
You are seeing a range of values for gain of 1.574-1.584 and for read noise 2.669-2.736

I consider that to be pretty good agreement.

Mark
Takahashi Epsilon 180ED
H-alpha modified Sony A7S
http://www.markshelley.co.uk/Astronomy/

Offline poochpa

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Re: Interpreting BasicCCDParameters Script Report from OSC Camera
« Reply #2 on: 2020 January 15 10:09:25 »
You are seeing a range of values for gain of 1.574-1.584 and for read noise 2.669-2.736

I consider that to be pretty good agreement.

Mark

Yes, obviously, Mark.  Other values in the report vary significantly between columns, so I’d still like to know what the columns represent with a color camera.

Offline sharkmelley

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Re: Interpreting BasicCCDParameters Script Report from OSC Camera
« Reply #3 on: 2020 January 16 08:59:08 »
You are seeing a range of values for gain of 1.574-1.584 and for read noise 2.669-2.736

I consider that to be pretty good agreement.

Mark

Yes, obviously, Mark.  Other values in the report vary significantly between columns, so I’d still like to know what the columns represent with a color camera.

The Bayer matrix has blocks of 2x2 pixels and in each block there is a red, blue and 2 green pixels - making 4 channels.  Each column in the report represents one of these channels.  So there is a column for the red channel, a column for the blue and 2 columns for green.  However the column order is not always clear.

Mark
Takahashi Epsilon 180ED
H-alpha modified Sony A7S
http://www.markshelley.co.uk/Astronomy/

Offline poochpa

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Re: Interpreting BasicCCDParameters Script Report from OSC Camera
« Reply #4 on: 2020 January 16 17:26:34 »
You are seeing a range of values for gain of 1.574-1.584 and for read noise 2.669-2.736

I consider that to be pretty good agreement.

Mark

Yes, obviously, Mark.  Other values in the report vary significantly between columns, so I’d still like to know what the columns represent with a color camera.

The Bayer matrix has blocks of 2x2 pixels and in each block there is a red, blue and 2 green pixels - making 4 channels.  Each column in the report represents one of these channels.  So there is a column for the red channel, a column for the blue and 2 columns for green.  However the column order is not always clear.

Mark

While that explanation initially makes sense to me, where did you get it from? I have seen others guess that, with an OSC camera, the first 3 columns represent rgb (and they're so labelled) and that the 4th column is some kind of composite. Another explanation is that the columns represent the particular bayer pattern, in order, for that camera.  It would be nice if the developer(s) of the script would weigh in or if there were some documentation on it, but I haven't found it. If the 4 columns represent the bayer pattern, then I'm puzzled why some measurements - dark current, for example - show a variation greater than a factor of 4 in the measurements.

Offline sharkmelley

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Re: Interpreting BasicCCDParameters Script Report from OSC Camera
« Reply #5 on: 2020 January 16 17:54:13 »

While that explanation initially makes sense to me, where did you get it from? I have seen others guess that, with an OSC camera, the first 3 columns represent rgb (and they're so labelled) and that the 4th column is some kind of composite. Another explanation is that the columns represent the particular bayer pattern, in order, for that camera.  It would be nice if the developer(s) of the script would weigh in or if there were some documentation on it, but I haven't found it. If the 4 columns represent the bayer pattern, then I'm puzzled why some measurements - dark current, for example - show a variation greater than a factor of 4 in the measurements.

There's no need for guessing what the columns represent - I arrived at the explanation by looking at the script!

Also the calculation of dark current is erroneous:  https://pixinsight.com/forum/index.php?topic=11800.0
That's why you are seeing the large differences in "dark current".

Mark
« Last Edit: 2020 January 17 04:47:38 by sharkmelley »
Takahashi Epsilon 180ED
H-alpha modified Sony A7S
http://www.markshelley.co.uk/Astronomy/