Possible light leak on ZWO ASI 1600MM-C?

[btalcox0715]

https://imgur.com/a/fDJz5L6

 

Anyone have any ideas on this? I’ve had my 1600MM-C since September 2016, and occasionally I’m battling issues with what is occurring in upper right. It’s never in same position (I’ve seen it in lower left coming from the vertical portion of frame), and my obvious first guess is a light leak.

 

My guide camera has a pretty bright red light (Orion SSAG) that I’ve covered up, and the next light I’m planning on covering up is the red ON light from my Orion Sirius mount.

 

A bit ago, I turned on live view with everything connected and telescope cover on, and was shining lights all over the imaging train, but nothing was indicating a light leak. I even did a single 300 second “dark” while shining light in different places in 30 second increments. I’ve never seen this occur while taking my normal darks, as I’ve had my entire imaging train covered and put in the dark.

 

Thanks!

[Wyvernp]

I think this could be to do with a very bright star just out of frame, based on the location and the angle of the light i'd guess the star Acrab.

[btalcox0715]

8 hours ago, Wyvernp said:

I think this could be to do with a very bright star just out of frame, based on the location and the angle of the light i'd guess the star Acrab.

See with Acrab, I’d expect the light to be shining directly down, based on the orientation of the FOV. Acrab is directly above TYC-6209 (the brightest star in my image) 

[Ken82]

It’s a bright star hitting something internally and shinning onto the sensor. 
 

I had this problem using 2”mounted filters. Although I’m using a much larger sensor. You can see the first image is with the 2” filter in place when I rotate the FW the problem is gone - 

[btalcox0715]

1 hour ago, Ken82 said:

It’s a bright star hitting something internally and shinning onto the sensor. 
 

I had this problem using 2”mounted filters. Although I’m using a much larger sensor. You can see the first image is with the 2” filter in place when I rotate the FW the problem is gone - 

Any tips on removing it? I can’t say that I noticed it or saw it in Live View in APT. Really frustrating to have to crop my photos so much to completely rid it

Edited June 14, 2020 by btalcox0715

[Ken82]

4 minutes ago, btalcox0715 said:

Any tips on removing it? I can’t say that I noticed it or saw it in Live View in APT. Really frustrating to have to crop my photos so much to completely rid it

Yea I couldn’t really see it on live view either but it was happening on all my images. So I tried with live view and vega just off axis and the problem was clear. when I then rotated the FW it was gone 😀

I would say try and find the source. Get a very bright star like vega just off axis. What filters are you using 1 1/4 ? If so rotate the FW to an empty slot and see if it appears. if so you know it’s the filter cell. 

if it is the filters you could try moving them closer to the sensor or look at a larger set??
 

How often does it happen ? For me it was literally every single target which was so annoying! 
 

 

 

[btalcox0715]

25 minutes ago, Ken82 said:

Yea I couldn’t really see it on live view either but it was happening on all my images. So I tried with live view and vega just off axis and the problem was clear. when I then rotated the FW it was gone 😀

I would say try and find the source. Get a very bright star like vega just off axis. What filters are you using 1 1/4 ? If so rotate the FW to an empty slot and see if it appears. if so you know it’s the filter cell. 

if it is the filters you could try moving them closer to the sensor or look at a larger set??
 

How often does it happen ? For me it was literally every single target which was so annoying! 
 

 

 

I use the Orion narrowband (HA, OIII, SII) and the ZWO LRGB filters. All are 1.25” mounted. Also, I have the ZWO EFW Mini. Wonder if 31mm unmounted would be any better. 
 

it doesn’t happen all the time, but it’s frequent enough 

Edited June 14, 2020 by btalcox0715

[uhb1966]

Are you using a Newtonian? Some have potential light ingress via their back side...

[btalcox0715]

3 hours ago, uhb1966 said:

Are you using a Newtonian? Some have potential light ingress via their back side...

No I’m using a Sky Watcher Esprit 80 

[sharkmelley]

Your best bet is to take some additional exposures with the frame shifted.  That reflection will then move position (relative to the star field) and that will allow you to replace the existing artefact with clean data.

Mark

[Ken82]

11 hours ago, sharkmelley said:

Your best bet is to take some additional exposures with the frame shifted.  That reflection will then move position (relative to the star field) and that will allow you to replace the existing artefact with clean data.

Mark

Yea I would agree, although when I had this issue by shifting the frame slightly could introduce the problem on the other side from a different star. 
 

In the end the only thing that worked was changing the filters to larger 50mm unmounted. 
 

I’m not sure what the recommended Filter size for you camera is ?(maybe some one can help with that?) but I think 31mm sounds about right. 
 

I think the jagged edge of the baader 2” filters may also have been a contributor for me .