Mean and SD Units on Histogram

[mike77345]

Robin,

I have a 12-bit camera (ZWO ASI290MC). On my histogram at max resolution the maximum reading is 255 for the mean. For a 12 bit camera this should be 4096. Why the difference?

[turfpit]

Mike

In File > SharpCap Settings > General tab what do you have for the highlighted?

general-settings.JPG (61.04 KiB) Viewed 2197 times

Dave

[admin]

Hi,

Have you put your camera into 12 bit mode by selecting RAW12 or RAW16 as the colour space instead of RAW8 or RGB 24. To me it sounds like you are still in an eight bit colour space.

Cheers, Robin

[mike77345]

Hi Dave and Robin,

I did not have the settings box checked for saving the 12 bit to the FITS format. I also had the file format set to AVI. I realized after I sent my note that one has to specify the correct color space and file format. I have the ZWO ASI290MC planetary camera which is also DSO capable to a limited extent. I wanted to try taking some DSO images for practice before I invested in a 16 bit cooled camera. I did have a couple of questions.

1. My camera does not show a RAW12 setting. Only RAW8 and RAW16. Am I correct is assuming I should choose the RAW16 with the FITS file format
and make sure the settings box is checked?
2. In the settings box it says "Read Documentation". Does this refer to SharpCap or the ZWO camera?

Thanks again. I really like the SharpCap Pro software for CMOS cameras. I was using APT but find it better for DSLR cameras.

Mike

[turfpit]

Mike

I did not have the settings box checked for saving the 12 bit to the FITS format

In File > SharpCap Settings > General tab that is correct for most (normal) use. Best left as the default unchecked.

A search on astrobin.com for your camera turns up 9 pages of images https://www.astrobin.com/search/?q=asi290mc&page=7 .
There are some DSO's in the results, so should give you an indication of what you could expect.

Depending on camera manufacturer you may see RAW8/RAW12, RAW8/RAW16 or even just RAW16 (e.g. my Atik 314E) offered.

• For deep sky, I always use highest bit depth available with the camera because I want detail. viewtopic.php?f=16&t=1871

• For lunar/planetary, I always use 8-bit because I want highest possible frames per second. I could use higher bit depth but its a trade-off and really depends on the atmospherics at the time/location.

• For lunar/planetary I always use SER capture format, because these days I am capturing 5,000 - 30,000 frame videos. SER handles the >10Gb files without issue. viewtopic.php?f=16&t=1675

In the settings box it says "Read Documentation". Does this refer to SharpCap or the ZWO camera?

Reading both will do no harm.

At the end of the day, I have found that there are no hard and fast rules but only 'guidelines'. Sometimes it is better to just try things and evaluate the results.

Dave

[admin]

Hi,

Yes, RAW16 is the way to go if you want the full bit depth of the camera. As Dave points out above whether you want to do that depends on the type of imaging you are doing. Some cameras show the true bit depth in the name of the RAWXX option, but for the ZWO cameras you get RAW16 showing even if the true bit depth of the camera is 12 or 14 bits.

Cheers, Robin