[Zuts]

Hi,

I was trying to collimate my 9.25 F10 SCT with an artificial star at home. With the longest distance I could put between the star and the scope ( in my backyard) I could not reach focus with the eyepiece in a diagonal.

By pulling the eyepiece out around 20 cm from the diagonal I could reach focus.

I still had about a metre of backyard left so moved the star back this distance however the focus point had only moved in around a few centimetres.

With a 20mm eyepiece in a 2350 mm scope how much extra distance would I need to reach focus?

Since the magnification is around 100x is it

additional backfocus required by magnification, ie around 20 cm by 100 = 20 m?

The scope is inside the house and the star is on the back fence. There really is no more room. Would it work if I moved the scope say a metre closer to the star to give me room and got a poly pipe to go the extra 20cm of backfocus?

Cheers
Paul