|
Most newt focusers only have about 50mm / 2" of travel, that is all that is needed unless wanting to use photographically too.
Do you want more in travel or out travel. If it only intrudes about 25mm when racked in where does it sit when an eyepiece is in focus. If you are talking about more travel that would imply more travel outward unless you are trying to get a camera to focus which would mean intravel, that creates another set of problems.
What are you trying to achieve by having a longer drawtube. Most newts work perfectly fine with a little intrusion by the drawtube. If wanting more out travel just add an short extension tube though if using the same eyepieces etc that would mean racking the drawtube in further so that it would intrude into the lightpath a bit more and defeats the original premise.
|