2" extension tube for visual Paracorr

[Bender]

I bought recently a visual Paracorr for my newt. As the scope needs usually a 50mm extension tube to come into focus I put the Paracorr into the tube but it turned out that the Paracorr is slightly longer.

Unfortunately I can only find tubes with 50mm or 80mm, the first to short for the Paracorr and the second to long to get into focus.

Does anyone know of a extension tube that is just long enough for the visual Paracorr ( guess 60mm should do)

I could of course use the 50mm tube and let the Paracorr stand out but I don't like the look of this setup

Thanks

Andre

[sixela]

Watch out: the Paracorr actually requires a bit of focuser in-travel, so count on using roughly 15mm less out-travel (it varies, because if the visual Paracorr tunable top is set correctly the Paracorr, unlike your eyepieces, always ends up in the same spot.)

The Paracorr itself is pretty long. Can you install a 2" parfocalisation ring on its barrel so that you can just reach focus with the original focuser racked out? Try to see if you can make the partially inserted Paracorr work without extension tube (of course, ensure there's enough barrel left inserted for it to be stable!)

You might also be able to win a centimetre or so by moving the primary forward on its collimation bolts (assuming the springs are firm enough not to render collimation less stable).