Capella HELP PLEASE!!!

Comment

Comment by Russ Ruggles on October 29, 2014 at 12:34pm

Phil
As a diehard Celestron SCT owner I've read in the past how some off brand FR snuck through with less then quality optics. I bought a used Celestron brand name FR and have never had an issue. I'm not say that this is your problem but the easiest way to find out is the processes of elimination.

Based on your gear listed and assuming the Canon T1i has produced fine images before my first guess still stands. Even if the FR was slightly "off axis" because it was screwed in to the OTA back I suspect that only the stars would be egg shaped from left to right and that reflection wouldn't be quite that bad.

One question - I didn't ask was what ISO setting you are using. Oh and are you using some sort of dew shield to minimize the possibility that stray light is entering the OTA?

In PHD you can enable the graph. Once you start guiding it will keep a record of the guiding pulses and tracking. You'll see red and blue lines - the flatter they are the better your guiding. This is bad - https://www.flickr.com/photos/edhiker/5575358664/

This is good - https://www.flickr.com/photos/astronewb2011/8898208296/

Are you using PHD2 yet??

Russ

Comment by Philip A Cruden on October 29, 2014 at 11:50am

Hi Russ, I new you would come to the rescue, thanks. The image is full frame. Here is some more info. CGEM-800, SCT8, Antares f6.3 reducer, Guide Scope Orion ST-80, Guide Camera ZWO120MC connected with a GPUSB, PHD, Backyard EOS. This is a single image and the only processing was done on the raw file to darken the blacks. So no stacking at all.

On this occasion I had the reducer screwed right into the barrel. Other times I have had it plugged into the external Crawford focuser but for this session I removed the Crawford......I am not sure if that makes a difference?

As you have suggested I will take a photo tonight without the reducer. When I bought the reducer the folks at Optcorp suggested the Antares one because it was made by the same manufacturer as the celestron but $50 cheaper.

Comment by Russ Ruggles on October 29, 2014 at 11:16am

Phil

It's good to see you're getting started on this.
OK - I'm pretty sure that's a reflection on Capella we're seeing. Assuming this is the full frame of the image (not cropped) I would guess this is caused by the focal reducer. Try taking one without it to see if that indeed is the case.

While your stars are an assortment of shapes corner to corner the stars in the center are reasonably round. This suggests that the FR is not quite correcting the optics as well as they could be. What brand name is that FR?

I would ask that you provide a little more info for me as well - Scope size, mount model, autoguide camera and software which will help in assisting you.
Also, did you do any processing to this image?

Thanks
Russ

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