Collimation help - Classic Cassegrain

[AstroRuz]

Hey everyone

I've got a 8" f12 classic cassegrain telescope at the moment and before I began using it in any serious capacity I thought I'd check collimation

 

The diffraction pattern seems pretty good, pretty centered etc 

 

But upon focusing and taking a test shot (30" ISO12800) I'm greeted by this horrendous halo around the star that seems to me to be a collimating issue 

 

Camera was a stock 80D with an IDAS D2 clip in filter and I was pointed at Arcturus

 

I'm not sure where else to go. Adjusting the primary didn't seem to change anything and the secondary seemed in the middle already. 

 

Any help is appreciated

 

Thanks,

Ruzeen

Edited July 20, 2020 by AstroRuz

[AstroRuz]

Forgot to attach the images!

[bottletopburly]

Possibly off the filter try without 

[AstroRuz]

1 minute ago, bottletopburly said:

Possibly off the filter try without 

Was considering that today that it might've been the filter. Just would've thought if it was the filter, then there wouldn't be the donut in it. But won't hurt to try without it anyway 

[johninderby]

Here’s the Orion manual with colimating instructions for the scope. Same scope just black instead of TS white 

https://nimax-img.de/Produktdownloads/62478_1_Anleitung-EN.pdf

[AstroRuz]

13 minutes ago, johninderby said:

Here’s the Orion manual with colimating instructions for the scope. Same scope just black instead of TS white 

https://nimax-img.de/Produktdownloads/62478_1_Anleitung-EN.pdf

Ah awesome I'll give that a read!

[Stuart1971]

That collimation looks pretty darn close to me, something else is at play there...maybe a reflection from the filter... 👍