Quote:
Originally Posted by Moon
Thanks David
In case anyone is considering something like this, I already received confirmation that it does NOT fit in the 3.0" Feather Touch.
James
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That's interesting - how was it confirmed? You made me paranoid so I just went down to the observatory and measured the OD of the Keller corrector and the ID of the focuser with my new Digital Caliper (accurate to 0.03mm). The ID of the drawtube was 76.27mm and the OD of the Keller corrector was 76.18mm, leaving about 0.09mm clearance (close to the 0.125mm specified value difference given the caliper accuracy, and also the fact that an OD reading may be too large and ID too small if you are not very careful taking the reading).
The 76.18mm (+/-0.03) is virtually spot on for the theoretical 76.2mm (3") diameter of the Keller corrector. I would be very surprised if FeatherTouch did not allow some clearance. Of course, it could be a QA issue on either side.
One other thought - I have found with my 2" Moonlite Crayford that because I have the pressure adjusted quite high (to try to cope with the weight of my STL-11000M), that my 2" laser collimator will scrape the bottom of the draw tube when I push it in. When I ease off the pressure, it goes in smoothly. So the extra pressure will tend to deform the drawtube very slightly. I think a 3" Feathertouch is a rack and pinion though? So may not be the problem here as it doesn't rely on high pressure on the draw tube.
