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View Full Version : DFK31 Coronado PST and lines



Drrobin
July 15, 2012, 21:50:40
Hi,

/just tried my DFK31 on a Coronado PST and I appear to be getting parallel dark lines on one side of the image. The camera doesn't appear to do this with other telescopes/filters, even white light solar filters and if I take the DFK out and replace with a webcam of similar pixel size and resolution I don't see the lines.

I tried different exposures and YUY/Y800 but the problem seems to be always there.

Does anyone know if there is a fix for this? Either in the camera or in IC capture.

Stefan Geissler
July 16, 2012, 09:08:45
Hi,

This looks like an interference of the H-Alpha filter you may use and the sensor glass. But I am not sure about this. May be an astronomer or the manufacturer of your telescope knows more about this effect.

Drrobin
July 16, 2012, 15:19:24
Hi,

This looks like an interference of the H-Alpha filter you may use and the sensor glass. But I am not sure about this. May be an astronomer or the manufacturer of your telescope knows more about this effect.

Hi Stefan,

Thanks for the quick reply. Yes, it does look like a diffraction pattern. I did rotate the camera by 90 degrees and the pattern stayed in the same place on the camera, I was thinking it would move round?

Do you know if the IR filter on the front of a DFK31 is removeable? I have never taken the retaining ring with the C/CS thread out, but does this hold the glass in place? I think I would like to try it without the glass, just to be sure. Otherwise a new camera might be needed and I would possibly go for a DMK21.

Regards

Robin

Stefan Geissler
July 16, 2012, 15:45:31
Hello Robin,


Thanks for the quick reply. Yes, it does look like a diffraction pattern. I did rotate the camera by 90 degrees and the pattern stayed in the same place on the camera, I was thinking it would move round?

Well, if it was an interference with the sensor, then the pattern should move when the camera is rotated. The camera itself can not create such a pattern, which means, there must be some optical stuff. I am not an astronomer, therefore, I am the wrong person to ask for these rings. (They are not Newton rings?)

The IR filter is not removable. However, not without dismounting the complete camera.