IC2177 Ha

[peter_4059]

Finally some clear nights to play with the belt modded EQ6. I'm still experimenting with guide settings but I'm getting some quite low RMS values. This image is 28x10min subs over two nights this weekend taken with the QSI and ED80. I've got a bit of tilt that I'll need to sort but apart from that I'm really happy with how this setup is working.

Full res version here:
http://astrob.in/88569/0/

[strongmanmike]

Yeah the stars look very slightly elongated diagonally L-R I guess - you use a guide scope don't you? could it be differential flexure? Regardless of this the image looks pretty good Peter with some really nice details. This region must be getting low now?

Well done

Mike

[peter_4059]

Thanks Mike.

I think the elongation is mainly in the bottom left and right corners. I've had the feeler gauges out and it looks like the flattener is sitting square in the draw tube.

Ive got a guide scope but it is pretty rigidly attached to the main OTA although the borg helical focuser has developed a bit of slop.

[strongmanmike]

Hmmm? Ok I see what you mean :confuse3:... well looking at that image train, as far as piggyback setups go, you look to have as good as you are gunna get in that department, nice. I see you have the DSI supported underneath by a bolt, is it just resting on that or is it screwed into the camera housing? If it is screwed in then I think you must be right, something is not sitting square :question:

Mike

[peter_4059]

The bolt was a quick fix for the slop in the focuser. The camera is just sitting on it at the moment. I'm thinking about changing back to the ZWO camera as this has smaller pixels than the DSI and also has a threaded hole in the side so I can fix the guide camera properly.

[strongmanmike]

Well how about a tight rubber band in the meantime? :) That's about the only area I could imagine any DF might originate from in that image train..?

Mike

[RickS]

Did you look at some short subs to determine if there is any elongation in them, Peter? Might help you diagnose the problem.

Cheers,
Rick.

[peter_4059]

How about this...

[peter_4059]

I didn't think to try that but I am getting pretty consistent elongation in the bottom two corners in most images so I suspect tilt is the issue. I think I need to try adjusting the position of the flattener to see if it gets better or worse.

[allan gould]

How was the guiding Peter with the new belts? Very interested as I havnt tried mine out under the stars but from your image it looks pretty good.
Allan

[peter_4059]

Here's a nice period from Friday night. I'm still seeing some spikey periods but I think it is seeing related as I can have a long period of very smooth operation at times.