SharpCap Forums

My problem with banding in lights and darks may be getting worse.
I have tried 2 different power supplies 2 different USB 3.0 cables from the 26C to the laptop, and more recently a different laptop and the problem doesn't go away.
THe camera (Altair 26C) has been checked out by Altair and is working perfectly.
Equipment and software
Altair 72EDF
Altair 26c camera
SharpCap for recording images
I suppose I could try different imaging software. Any ideas?

Hi,

this seems to be a pretty standard effect with a whole range of modern CMOS cameras. I believe that it is down to fluctuations in the power supply within the camera. Sometimes the effect varies in strength depending on the gain in use.

My experience is that this is never visible in the unstretched images, but almost always becomes visible in stretched images (if you stretch them strongly enough). It seems to be one of those things that you just have to deal with (like you have to deal with high read noise or bleeding of saturated pixels on CCD cameras). Stacking lots of frames helps, as does SharpCap's 'Banding Suppression' function - see https://docs.sharpcap.co.uk/4.0/#!2!Pre-processing and follow the guidance on how to set up the banding suppression parameters.

Hope this helps,

Robin

This IS in unstretched frames and the banding suppression seemed to just average the banding out a bit rather than just the middle.

Ah, well that is different to the banding I was thinking about then... Can you share an image showing the issue please?

The banding suppression will deal with very fine lines visible in the stretched image, not anything more than that.

thanks,

Robin

These thumbnails show the frequency and extent of the banding. This was i9maging Comet ZTF.

I have now had the chance to try out a newer laptop and still had the same problem. So now I have moved the whole rig indoors pointing out of the window imaging hills 7 miles away as it gets dark. I am using my original old laptop. I have everything set up identical to when I experience this banding. I am using the same 50m extension reel plugged in to the mains socket in the garden that I use when imaging. I am using all tyhe same software, Sharpcap, Stellarium and PHD2. I am connecting to the laptop from my desktop as I do when imaging and I am having bno problems at all - I am unable to recreate the banding. I cant think of anything that's different. If I open the lounge french doors and it was clear tonight I could image the Orion Nebula from the lounge and not have the problem I have when outside.

I had kind of the same problem you describe here.
In my case it turned that the power was the culprit. I made used of a non grounded power supply and mount and that caused the banding. Once grounded, it all worked fine.
Is there anything different when it comes to your power set-up you use outside and now inside?

Menno

No it's identical the same outside socket and extension lead.

Hi,

could it be related to the temperature of the equipment? When you set up outside, everything will get cold and may get a little damp. Indoors, it will be nice and warm.

I just had to have my Pegasus focus controller repaired by the excellent folks at Pegasus Astro - it was failing to work outside. When I sent them info about the problem they immediately knew that there had been a small number of cases where the clock chip on the devices became faulty. A faulty clock works pretty much OK most of the time, but the frequency drifts when it gets cold and once it drifts by about 2% the communication with the PC breaks down.

Not suggesting that yours is going to be the same issue, but it is a difference worth investigating between your astro imaging issues and your indoor imaging success.

cheers,

Robin

Well I do have the Pegasus Focus Controller attached (though I only used it manually as I haven't worked out how to set it up to autofocus - an
other thing I must read up on.

Hi,

I should point out that the pegasus issue just stops it from working and will not affect the images in any way. My theory is though that the temperature change may somehow affect your camera/laptop/cable/power supply.

Robin