[Jethro777 (Jethro)]

What is the focal ratio of my scope?
I have heard it doesn't change - it's fixed - so that would make it f/7.3 - but I have raised the primary mirror 28mm - so does that make it change for the purposes of calculating a secondary mirror size?

I calculated it now - it seems to still be f/7.3
26" to the secondary, then 5.3" from the secondary to the focal plane.
The primary is 4.3".
So, 26"+5.3"=31.3"
So, 31.3 divide by 4.3 = 7.27

After plugging it all in, it seems as though the current mirror (1.1") is too small by far. The recommendation seems to be - (according to bbastrodesigns anyway) 1.83"

I'm comparing that with the page from Gary. He says it's L divided by F.

f = Telescope’s focal length divided by the diameter of the primary mirror) (in my case, 7.3)
L= Distance from the center of the tube to the focal plane (In my case, 5.3")

5.3 divided by 7.3 = .726??

Now even more confused, lol.. C'mon - what have I done wrong?