[gregbradley]

Apparently GSO make a flattener for this OTA, well at least that is what I read on CN and even on Astronomics but so far I have not found it.

Thanks so much for the feed back Greg, much appreciated.[/QUOTE]

Also keep in mind Paul that an RC has no coma. So all the flattener will do it reduce star sizes off axis. A good one will also correct for other aberrations.

But I had a 12.5inch RC for a few years and never used the flattener. My images and those of others with 12.5 inch RC using a flattener looked awfully similar. So the gain is not necessarily massive but probably worth it if not too costly.

Tak often uses 106.2mm and there is often a tolerance of a few mm either side of that figure. I think they also use 86mm as well.

Looking at the image it would seem to be more tracking error although miscollimation is a possibility also. Did you use a Tak collimating scope to get collimation? Another hint collimation may be out is you can see a little black dot in the centre of some stars which is the secondary mirror showing through or perhaps focus was slightly off??

Greg.