Although the my Borg scope has a nice, heavy duty manual focusser I prefer for CCD work to make use of automated focussing provided via a DF-2 focusser from Finger Lakes Instrumentation. I also want to include the CFW8 from SBIG into the setup.
First, I make a direct coupling of the ST10 and CFW8 in the standard SBIG way:
Then I take my two adapters for connecting the DF-2 focusser to the CFW-8 (the bronze one is custom made, while the black one, called AD-2, is the
standard FLI adapter):
The bronze ring is just a spacer to avoid having the black adapter pushed up against the two screws marked in green on the CFW8 body (first image). Even
with this ring in place the thread of the black DF-2 adapter still extends ~3 mm into the CFW8 threading. After I have mounted these two adapters the camera
assembly looks like this:
Now I take the DF2 focusser:
and attach it to the adapter on the camera assembly. Two pointed setscrews (one marked with green arrow above) are tightened, pressing on the angled egde of the DF2
adapter, thereby pulling the two structures firmly together. The extended load capacity of the DF2 focusser is 15 in-lbs. Hence the total weight of the ST10+CFW8
(~3 lbs) with the center-of-mass roughly 2.5 inches behind the DF-2 should be well within specs. With these connections made the assembly now looks like this:
Finally, the camera assembly is screwed into the 7502 adapter on the Borg100ED:
Note the bronze spacer ring I have mounted just after the Borg helical focusser. This is to avoid having to rake this Borg focusser too far out which
I worried might cause some sagging due to the large extended load. Note also that the end of the Borg 7202 adapter is shiny; that's because I milled off
the outermost, unthreaded section. Without doing that the theads were only engaged over ~1 mm. With this modification the engaged thread is ~3 mm, adding
to the rigidity and minimizing the risk of thread damage. The whole setup is now finished:
Here's my mechanical mating page where you can see more examples of custom made adapters.
Comments greatly appreciated! (mikael@leif.org)