I have a 6" mirror ground very close to F/6 and was just wondering what the difference is between the F/6 or F/4 as far as the view in the eyepiece is concerned?

I know the different focal lengths mean different lengths of tube, but does F/6 give better resolution of close bodies like the moon and F/4 is better for deep sky viewing or is there another reason for the different focal lengths?

F/6 has been suggested as the best focal length for this mirror but i still don't know why F/6 is better than say F/4.

I've learnt a lot in the last month and have my telescope nearly ready for first light and as this is a project with my son, I want to get the best result possible.

Any help would be appreciated.

• F6 vs. F4 - bobmay - August 30, 2002 - 18:21 UTC
  • so it may depend... - slamhound - September 9, 2002 - 16:33 UTC