Weird Artifact

[Farooq]

I tried imagimg M15 the other night in LRGB, when processing the image i found that there is a weird artifact not sure what it is. on the face of it it looks like a reflection pf some sort.

Any ideas, it is not consistently repeatable. During the same imaging sessionearlier i did some HA of the cresent nebula, and after the LRGB i did some more Luminance only of M31 and i did not get this artifact in my images.

This same artifact has occured before as well.

Any suggestion on what it could be?

[GlassWalker]

If that was with photographic kit, I'd say it looks exactly like lens flare to me. What were you using at the time? I guess similar could happen to astro kit which isn't that much different.

[rfdesigner]

I tried imagimg M15 the other night in LRGB, when processing the image i found that there is a weird artifact not sure what it is. on the face of it it looks like a reflection pf some sort.

Any ideas, it is not consistently repeatable. During the same imaging sessionearlier i did some HA of the cresent nebula, and after the LRGB i did some more Luminance only of M31 and i did not get this artifact in my images.

This same artifact has occured before as well.

Any suggestion on what it could be?

light leakage on a filter wheel?.. I've come across several instances of this across the web.

[Farooq]

I am using an sbig 8300m and FW5 filter wheel. It seems a pretty tight fit all round, from CCD > Filterwheel >Extension tube> Field flattener >Focusser

I am reasonably sure there is cannot be any leakage anywhere in the imaging train.

I do live on the 7th Floor of an apartment block and well above the street lights and not far from an airport. I have only seen it on LRGB images and not any HA imaging.

So I am a bit confused as to the source.

[Farooq]

Ahaaaa!!!! I just came across the following on the Cyanogen website regarding the SBIG FW8, maybe it applies to the FW5 as well ?.

SBIG's CFW-8 filter wheel uses an optical sensor to detect filter wheel rotation. This may cause light to leak in to the CCD even though the shutter is closed. To correct for this problem, enable

Auto-Expose After Filter Change

. When enabled, the plugin will automatically take a single very short exposure at the highest available binning after every filter wheel movement. This flushes any excess light from the chip, preventing it from corrupting subsequent images.

[squeaky]

nah... you've caught a Klingon War Bird passing through at warp 6. Well done

[Hitesh]

Lol warbird, funny u say that I just had a patient speak to me in Klingon!

[Gina]

Optical position sensor in a filter wheel ??!! :eek: Incredible!!! I rejected that idea from my home made filter wheel knowing light could leak into the camera!!