Orion 190mm Mak-Newt Moonlite focuser install

The Orion 190mm Mak-Newt is a great scope for imaging.  With the corrector plate on front it provides pinpoint stars very nearly to the corners of my Canon 60D DSLR.  Trouble is they are no longer being sold by Orion.  I purchased mine second hand and have used it successfully for a couple of years.  Recently I decided I wanted to upgrade the focuser so that I could do automated focusing using Sequence Generator Pro (SGP).  I selected the Moonlite 2" Model CR Newtonian Focuser (with 2" travel) for several reasons.  First they have a good reputation and I read nothing but good things about them.  Second the authors of SGP use them, (seems like some at Moonlite use SGP), so I knew there would be good software support.  Third Moonlite already has an adapter plate specifically for the Orion 190mm Mak-Newt.


First I removed the old focuser.  I was a little concerned with the dent on the lower left side.  It didn't seem to be an issue with the old focuser as my images showed little camera tilt (analyzed via CCDInspector 2).  The old focuser was attached through screws from the outside.  However, to install the Moonlite I needed to remove the corrector plate as the screws had to be installed from the inside.  First I put painters tape across the seem between the corrector plate and the tube.  I did this to help me align the corrector plate when I went to re-install it,(though collimation would still be necessary).  Then I put the cover back on to protect the outside of the corrector plate during the process.  Next remove the six screws on the tube portion.  Once these are out the corrector plate has to be worked out of the tube.  It is a tight fit so work around the entire edge instead of just just trying to work one side.  Once removed I put the plate in a plastic bag to limit dust, etc. while I installed the focuser.



Front end with the corrector plate removed.









The installation of the Moonlite was a snap.  I ordered it with the the motor and it came pre-assembled with the motor and adapter plate for the Orion 190mm.  The adapter comes with a 1/2" spacer which I didn't need so wasn't used.  If using this for visual work it may be beneficial but since I am doing mainly imaging I need the top of the focuser to be less than about 58mm.  Moonlite provided longer installation screws which are required for my version of OTA.  My version has nipples that the focuser screws screw into from the outside.  The longer screws go up through the holes in the nipples and then into the adapter plate on the focuser.  The screws are stainless steel and so I painted them black to hopefully cut down on reflecting stray light.  The adapter plate seems to be large enough that the dent around the focuser hole doesn't seem to be an issue.  Now to get it under some stars to test it out.