[peter_4059 (Peter)]

For quite some time I've been messing with my imaging setup in an attempt to get nice round stars and a flat field across the image. Last night I finally had a breakthrough where it all came together. The final piece of the puzzle was the spacing between the flattener and the camera. For months I've had it pretty much bang on the 55mm as per the manufacturers recommendations. In a passing conversation with Troy (who has the same flattener) he mentioned that his performed better at 65mm so last night I gave it a try at 65mm. after a single 10sec frame I could see I had gone too far so I backed it off to 63 and finally settled on 61mm. Here's the comparison of the 55mm (manufacturers spec) and 61mm.

I'm very happy to finally have this sorted!

The moral of the story is don't assume the publicised spacing is the best for your imaging train.

Thanks for looking!