What is my problem?

[Snoani]

Evening all

I have just setup for a night of imaging and have trained my scope on the Horsehead and started the image run as usual.  However, I have just looked at the first light frame to find a 'streak' in the corner that I have never experienced before.  I wonder if anybody could provide some advice about what it may be? 

I am using an ASI 1600MM Pro on a Meade 6000 APO.  It is only the third time I have used the camera, but I did not experience this the first two time.  

I don't know if I have problem in the image train or whether it can be removed with calibration. 

Your help would be appreciated.

Jem

 

[JamesF]

Reflection of Alnitak off some part of the imaging train, perhaps?

Changing the framing might perhaps help.  If you search SGL for posts relating to the Horsehead and Alnitak you might find some other ideas.  My recollection is that it generates of a lot of complaints every winter :)

James

[alacant]

39 minutes ago, Snoani said:

the first light frame

How do second and subsequent light frames appear?

[Snoani]

Thank you for your suggestion James.  I ran a search and looked through numerous posts but couldn't find anything similar.  

All frames are showing the same issue so I decided to end the run on that filter and try others.  It is appearing on all filters apart from H-Alpha, which I assume is because the light frequency is being blocked.  I think that there must be something in my image train.  I am therefore undertaking a significant H-Alpha run tonight, because my mount is guiding as good as it ever does, and tomorrow I'll break down the image train to check for artefacts before the forecast clear sky tomorrow night.  

[symmetal]

It's a flare effect from Alnilam, the middle star in Orion's belt which is just out of the frame in the top left. I took a few frames around the Owl Nebula this evening and Merak, just out of the frame produced the same effect.

Alan

[symmetal]

Changing the framing to put Alnilam further away is the easiest way to remove it, but if you want to keep the framing, adding an extension to the dew shield in that direction, to act like a longer lens hood, could help. Although it's out of frame to the sensor it's likely within the imaging circle of the scope so any hood extension would probably have to bend inwards until the star is blocked from the scopes FOV, which may then cause diffraction issues unless the extension is really matt black. 🙂

Alan

Edited January 7, 2021 by symmetal

[Snoani]

Thank you both for your replies.  That makes sense and now that I have looked at the FOV on Stellarium, it makes complete sense.  I am frankly just glad it is not an equipment issue. 

I left my rig in tact last night and have just setup as I have a lovely clear sky currently, and I will continue to capture as it is and crop the final image.  

I very much appreciate your help with this.