general purpose micro-focusser?

[Robert_T]

Hi All, having resolved (well almost) the planetary camera issue the next item on my wish list is a micro-focusser to avoid mirror-shift in fine focussing while imaging - find my ability to get critical focus is letting down my images a little. I can use either 2in or 1.25 in accessories straight into the visual back on my Mewlon, just wondered what products might be out there that I could adapt to the task (failing buying something from Takahashi, which would cause grevious bodily harm to my wallet;) ). Motorised would be nice, but manual cool also. Any advice gratefully received.:)
cheers,
Robert

[[1ponders]]

Hi Rob, if your mewlon has the standard SCT thread at the back, probably the cheapest motorized is the non-motorised JMI , then Meade microfocuser(about $400), then the motorized JMI (about $500 and three speed). The JMI motorized can be used manually as well, but why bother :P

[Robert_T]

Thanks Paul, I think therein lies the problem as it doesn't match the standard SCT back. The mewlon visual back thread is much larger and can take 2 inch barrel accessories direct. Maybe something with a 2in sleeve to micro-up the focussing tube of a rack and pinion refractor would do the job? - if such exists and if the aren't too "thick". cheers, Robert

[[1ponders]]

I doubt that meade would have anything to do that job, but maybe drop JMI a line and see what you can come up with.

I had the Meade when I had an LX200 and it was ok for visual work but found it had too much backlash (well the one I had did) for autofocusing for astrophotography. I could do it manually but there was still a bit of hit and miss. I much prefer the JMI NGF-CM, there is still backlash but not as much I've found, plus I felt it gave better fine control