Strange lines on images

[lukebl]

Hi folks,

Can anyone suggest what's happening with my camera.

This is a stacked image of the Veil nebula, captured in 12x10 minute exposures with my Atik428ex with an HA filter.

If you zoom in on the lower left-hand side and stretch the image, you can see these strange evenly-spaced parallel lines.

The individual frames also show this effect, so it's nothing to do with the stacking program (DSS). It's also nothing to do with the filter, as other images with OIII and no filters show the same effect. I've never had this problem before. Any idea what's going on? Is there a fault with the camera?

Closeup

[symmetal]

I was going to say you were dithering in one direction only, but if it's also on the individual frames I would first try another power source just for the camera. Is it a switch mode or linear PSU? Capacitors in the PSU failing can cause problems like this giving a high frequency noise on the supply output.

Alan

[lukebl]

10 hours ago, symmetal said:

I was going to say you were dithering in one direction only, but if it's also on the individual frames I would first try another power source just for the camera. Is it a switch mode or linear PSU? Capacitors in the PSU failing can cause problems like this giving a high frequency noise on the supply output.

Alan

Not sure of the terminology, but it's powered via a Maplin XM21X regulated DC Power supply if that helps.

[symmetal]

That's a linear PSU that FLO used to sell so should be OK but it's worth trying another power supply to test the camera, just to rule out the supply being the cause.

If it's still there with a different supply I would suggest contacting Atik and see what they say.

Alan

[Whirlwind]

Do the bias and/or similar time length darks show the same feature?

[lukebl]

6 hours ago, Whirlwind said:

Do the bias and/or similar time length darks show the same feature?

The darks look fine, with no apparent lines. Power supply seems fine too.

This is a single 300 second exposure heavily stretched, followed by an image of the detail area showing the streaking.

 

[symmetal]

Did you give the darks and bias the same level of stretch as the image you posted. If they are clean and were taken when the lights shows this effect, then it's an optical effect which would be very odd, as it's so uniform over the image.

Alan

[Whirlwind]

It might be walking floor noise.  How well matched are your darks to the lights temperature wise (and the same for the flats?).  How old is your master dark that was used the calibrate the image?

Another example can be found here.  https://www.cloudynights.com/topic/467758-fixed-pattern-noise/

You can generally dither to remove it, but I would check how well your calibration frames are matched to start with.

 

[symmetal]

1 hour ago, Whirlwind said:

It might be walking floor noise.

That was my first thought when I saw it too, though the effect is visible on the individual lights, though to a lesser extent which I assumed were before calibration.

Alan

[Whirlwind]

I would try dithering to see if it removes the features. If you have fixed pattern noise in your images why would you not expect to see it in an individual uncalibrated frame?