Hi Bill,
The WO 50mm is what I used for awhile before I moved to a larger guide scope. I had to insert one 1.25" eyepiece extension to gain proper backfocus. Even with the threads full out there was not enough distance. Plus if you are too far unthreaded, you may start to jiggle and create flexure between guide scope and main scope.?
PEMPro is worth it in my opinion since you can do tracking analysis and upload a PEC correction curve right to the Gemini unit. With a good curve in place your guiding software should not have to work as hard and should be more accurate. PEMPro also uses your main imaging camera for more detailed star tracking than with your guide scope. You have a 60 day trial period, so really you can do the proper analysis and curve upload without have to buy immediately. Then you can try guiding with and without PEC turned on to see if it makes a difference in total error.?
Regards,
John
