Re: TUBE AND MOUNT DESIGN
bill nelson (billn@hpcvaac.cv.hp.com)
Mon, 10 Apr 1995 17:41:18 -0700
Some diagonals and prisms require as much as 3 inches of inward travel.
It is always possible to set the focus a bit high, and use extension
tubes if necessary for those inserts that require a lot of out travel,
such as a 3x Barlow.
This works best with a 2" diameter focuser - as you get a bit more
vignetting if you set the focal plane too far out on a 1.25" focuser.
Bill