mystery artefact

[alacant]

Hi everyone

The horizontal line top right. It appears on frames 1 to 16 of a total of 30 or so and won't sigma-thingy out when we stack it. Looked at the sensor and it's clean. 

I suppose the only option is to heal it. What a pain...

Any ideas anyone?

Cheers and clear skies.

1-16:

17-32:

sigma-clip with big hammer stretch:

[JamesF]

How odd.  It looks exactly the same in all the subs it appears in?  How long was each sub?

James

[alacant]

51 minutes ago, JamesF said:

How long was

Hi. Yes, the same on each of the first 16 frames. Maybe fading toward the latter part of the sequence. 7 minute frames IIRC.

[JamesF]

So it's there for the better part of two hours without moving and then suddenly disappears...

I'm sure of ideas, but I'm wondering if perhaps it's nothing in the sky and might be from the local environment.  Light leaking into the camera from somewhere perhaps?  That or aliens is all I can come up with.

James

[alacant]

Yep. Aliens. Has to be:)

[Davey-T]

Spider on the spider if it's a newt, that really doesn't make sense 😂

Dave 

[alacant]

Anyway. Stupid idea. A galaxy cluster with the wrong telescope...

[symmetal]

The 17-32 image is rotated 180 compared to 1-16. Did a flip occur between 16 and 17? This would imply light leakage getting in somewhere. Do you perhaps have a tilt adjuster in the train? I always put black tape around the edge of the adjuster as it can be a route for light to leak in.

Alan

[alacant]

1 hour ago, symmetal said:

Did a flip occur

Hi. Yes. Good point. It flipped. So that must be it. It's one of those awful slippery SW focusers, so certainly not light proof. The light source must be the screen of the computer. Or come to think of it, the mouse emits a bright light too.

EDIT: Yes, of course...The Moon.

Edited February 1, 2020 by alacant

[almcl]

Sounds like you've cracked it, but I think the artefact is present in the second sequence, just in a different place.  Not sure if that affects the diagnosis or not?

[JamesF]

41 minutes ago, almcl said:

Sounds like you've cracked it, but I think the artefact is present in the second sequence, just in a different place.  Not sure if that affects the diagnosis or not?

I'm inclined to agree that it's also present, now you point it out.

James

[alacant]

Yeah, dunno. Strange. There's no sign of it on the flat frames...

[alacant]

Rescued something but not very inspiring. It would look better with a bigger telescope anyway.

Can't heal the darn thing without losing some stars though.