Smart Histogram gave 200 blank images

[donwaters201]

I used the brain for the first time on M13 and got a reading of 16.4 s and gain of 138. I accepted the suggestions.

Then I started capture. When I open the capture folder and loaded the images in DSS, all were blank - totally black.

Next night I repeated the entered the settings manually and started capture, and all worked well.

I must be missing something.

Don Waters

[admin]

Hi Don,

first place to start would be the 'capture settings' files saved alongside each captured images - they record the camera settings in place when the image was captured. Have a look at one from the problem session side-by-side with the one from the session where everything worked and see what is different- the answer might spring directly from the differences you see, but do feel free to post one of each of those capture settings files here for me to have a look if you can't make anything out.

cheers,

Robin

[donwaters201]

The gain is 138 at 29 secs. for my ASI294 MC Pro.

When I load in GIMP and adjust the histogram, the image appears.

This is my first experience with the brain. The images are too faint to stack in DSS, so there must be something else to this.

If the brain selects the optimum settings, I don't see how to proceed with an image that can't be stacked.

Thanks.

Don

[admin]

Hi Don,

can you share an image and a capture settings file corresponding to it? I would have thought that ~30s at 138 gain would give decent images for a 294MC, so I am wondering if something else beyond the gain and exposure was set in a way that is adversely affecting the image.

cheers,

Robin

[donwaters201]

Thanks.
Here you are.
Don

I had to compress the original .tif to .jpg to be < 1MB.

[admin]

Hi Don,

I think the problem is that you were running the camera in 'RGB24' mode - that means that the images being output from the camera are 3 colour channels (R,G,B) with 8 bits per colour channel. The use of 8 bit output means that there are only 256 possible brightness levels, so lots of faint detail that would have been present is being lost due to the values being rounded to the nearest of the 256 available levels.

The correct mode for deep sky imaging is RAW16, whereas for planetary, lunar or solar you would be likely to use the default 'RAW8' mode. RGB24 is really there for terrestrial imaging use cases where you might want to save to AVI or JPG (maybe microscopy).

Unfortunatele the fine information cannot be recovered from your saved images because the choice of RGB24 meant that it was discarded before the image information even reached SharpCap - sorry not to be able to help from that point of view.

thanks,

Robin

[donwaters201]

I agree.

I am new to some of the details of modes, formats, etc. and thought that RGB24 was correct.

DSS would not stack them and reading more about DSS, I see that they recommend RAW16 and let DSS debayer.

The images I got using the RAW16 worked fine (although I have not tried the debayer yet.)

Thank you.

Don

[turfpit]

Don

You might find [url]viewtopic.php?t=2552[/url] explains some of the deep sky imaging concepts.

Dave