[DavidH]

Hi All,

Have been grinding and polishing a 6" blank for the past few months. Have got to the stage of being able to test the mirror and found a lot of turned down edge. Have been able to get rid of some of it as the Ronchi images show. The progression is from left to right. There is still a fair amount of TDE in the final image. Am looking for advice on how to proceed from here - continue to move towards a sphere, or try to parabolise. Was aiming for about f5, but have ended up at around f4.7.

Thanks,
David.