Triangular Stars

[Mcrogers1]

Hello,

This image is a 5 minute sub using the red fllter with a refractor and not using a focal reducer/corrector. What can cause the triangular stars in the center?

Thanks.

 

Mike

[Davey-T]

Looks like tilt in the focuser possibly,  stars at top left are badly misshapen.

Dave

[zicklurky]

Yeah I'd say there's some tilt as well. Make sure the camera is square to the telescope, and if there's a bit of sag in your focuser then try and tighten it down if you can.

[Mcrogers1]

Thanks, I'll run CCDInspector when I can see the stars again.

[Astrofriend]

For me it looks that it's to some part a tracking error, the triangle is in the same direction to all what I can see. But when I read what equipment you have I think you have control over that. Have it worked correctly earlier? Was the telescope cool down enough?

 

/Lars

[Mcrogers1]

I ordered some screw in adapters so I want be connecting the imaging equipment via the stock compression fittings. Should make it more rigid. I use the FeatherTouch focuser SI recommended for my imaging gear but they come with compression fittings. Hopefully the new adapters will take tilt out of the equation. CCDInspector stated that I had a lot of tilt and bad collimation. I guess the tilt is throwing the collimation off because I took the refractor out of the box and put in on the mount. This refractor can't be collimated so the new adapters are my last option.

The tracking is good and the scope was ice cold because it stays in an unheated observatory.

 

[Astrofriend]

Yes, screw in adapters are much more stable. I have it everywhere.

 

You can read here how I built my APO recfractor and field flattener:

http://astrofriend.eu/astronomy/projects/project-mechanical-construction-adapters-for-apo-refractor/project-mechanical-construction-adapters-for-apo-refractor.html

 

And now I change to this:

http://astrofriend.eu/astronomy/projects/project-three-inch-flattener/project-three-inch-flattener.html

 

Maybe some useful information for you.

 

/Lars

[Mcrogers1]

Thanks, Astrofriend but I have trouble building paper airplanes.