Extension tube

[cookie8]

Using a Philips900nc;a 5x powermate & a 12"LB for planetary photography. Do I need extension tube to bring image into focus and what length?
Anyone with experience out there?
Thanks:screwy:

[gbeal]

No experience with the LB stuff, but in my 10" if I can focus an eyepiece first in the Powermate (I use both a 2.5x and a 5x) then the ToUcam is close to being in focus as well. Best suggestion is try it first.
Gary

[AlexN]

in my 8" with the 5x I still have about 2cm of in-focus and 2.5 of out focus.

I use around 8cm worth of extension tubes to get a rather massive image scale, and still have plenty of focus room to play with....

I dont think you will have any troubles using the 5x + 900NC + 12" at all...