Is this mirror flop, diff flex or just bad drift?

[Aeseir]

Hey guys,

Other day i completed my package (guidescope and autoguider) so decided to do some shots. Did only basic PA since goal was to get the guidescope tested and working since i never done it before.

I got some nice images but for one i had a decent amount of stretching and my mate advised that its most likely mirror flop, which crushed me considering this is brand new setup (less than 4 months old).

So i thought i upload my two images (tarantula and orion nebulas) for you guys to give me some advice whether its mirror flop, drift or differential flex.

[Owmuchonomy]

Hi, to help us diagnose this can you advise what kit you have, mount, scope etc, and if you have single subs that are affected it may be better to post these to look at together with the parameters used.

[Leveye]

How long are the exposures here?

[Aeseir]

I thought i added it, must have removed by accident.

Mount: CGEM Computerized Mount

Main OTA: C8-XLT (CGE) (8" SCT)

Guidescope: Orion ShortTube 80 Refractor

Rings: Orion 105mm ID Guide Scope Rings

Guidecamera: Orion StarShoort AutoGuider Pro Mono Astrophotography Camera

Imaging Camera: Canon EOS 40D Unmodded

[Aeseir]

Arghhhh keyboard too sensitive.

Those are single subs that were ~333 seconds (5.5 min). It was a test night to learn to use my completed setup. ISO 1000.

DSLR somehow reverted to JPG so i had only them to play with.

Used the basic polar alignment that came with mount (no drift alignment).

[Leveye]

I have a Celestron C8 thats about 2030mm and can get nice round stars autoguiding at over 5 minutes. I think you need to go back to start and do everything over. Your initial mount leveling,basic aligning,balancing, Most of the time If I have any issues with oblong stars  it's usually from from it not being balanced in either DEC or RA. It could be from flop as well though.Depends on what the Alt of the objects were.

[Owmuchonomy]

What proportion of your M42 subs showed the star aberration? I can't see an issue with the other photo, other than colour balance?

At these focal lengths guiding/imaging without an OAG can be a stiff challenge.

[Aeseir]

Unfortunately M42 i had only managed to get one good photo as others got ruined by incoming clouds.

[Owmuchonomy]

I would suggest you compile a set of subs to see if there is a consistent problem rather than assume there may be one just from a single sub. For example, the mount may have been knocked, or a cable snagged etc,....

[Aeseir]

Thanks. I'm gathering all possible reasons this may have occured for M42 and am slowly fixing things up.

If for some miracle we get clear weekend im implementing all these little fixes and trying again. It would really suck for it to be mirror flop considering its brand new equipment.

Makes me want to design and produce my own equipment lol