ATM Focuser Postion

[Brad Davy <bdavy@bigdog.fred.net>]

I ordered my eyepieces today, and am down to waiting for optics to arrive.
While I wait, I'm trying to make sure I properly identify the focuser location. 

I built a simple helical focuser using PVC Electrical Conduit fittings.
I'll spare the details for now, but the results are it is 1-3/8" high from
the outer surface of the tube.  Cost about $4 total.  Unfortunately, it only
has about 5/8" travel from fully in to fully out.  Obviously, accurate
positioning from the mirror will be critical.

I ordered the Orion Sirius Plossl eyepieces(40mm and 10mm) and the 2x
Barlow.  Has anybody ever determined the focal plane for these eyepieces?  I
need to determine this so I can ensure the focuser has sufficient travel for
both eyepieces.  Anybody got any suggestions?

Thanks.
Brad
bdavy@fred.net               http://www.fred.net/bdavy/home.html
bdavy@nox.cs.du.edu