Lightbox flats help

[OneCosmos]

Hi,


I have one of Peter Miller's excellent light boxes to take my flats. This is my second box and I have used my first one many times with both telescopes and camera lenses, using astro cameras and DSLRs.


I used the new box for the first time this morning to take some flats using the Canon EOS Ra and the Sigma 105mm f/1.4 lens that i used to capture comet Leonard last night.


Unfortunately the light box with this setup produces a weird banding I've never seen before - see photo. Peter is at a loss so just wondered if anyone here can think of what the problem may be.


Cheers,


Chris

[multiweb]

It could be a dew heater or power cable close to the camera USB feed.

[OneCosmos]

Thanks Marc you were very close to the marK and led me to discover the problem.

My original light box had a simple knob to turn to dim the light the new version has a fancy attachment. With it I get the banding, without it I don’t.
Without the dimmer the light is very bright but the DSLR can do 8000th second an Astro camer couldn’t and this would have a problem I presume.

See pics of the module referred to which I hope I can attach to the original post

[sunslayr]

Have you tried adjusting the shutter speed? It looks similar to the banding you get when you shoot video and the framerate doesn't match the lights mains frequency. Setting the brightness up and shutter speed faster might help.