GEM28-- Much improved over the CEM25P
I purchased the GEM28/iPolar/Case/LiteRock combo and received it Friday. Set up and tested Sat. night using a BORG 90F3.9 + 200mm guider set up that weighs about 18 lb. This mount seems lighter weight than my CEM25P with the 2" tripod, which is always a good thing. I like the altitude adjust mechanics much better that that of the CEM25P and the GEM45G. Easy to adjust knob without having to use an allen wrench as a wheel lever. ISSUE: Can’t seem to tighten elevation lock adequately, however elevation knob adjuster is a big improvement. I didn't take any stars off for this, as it may be an easy fix. Pole align much simpler with iPolar as compared to the Polemaster on my CEM25P. This mount actually has the polar camera installed correctly. Pole align with altitude adj knob actually makes the red dot move up and down. On my GEM45G the camera must be rotated 90 deg off as the adjust settings are reversed: altitude adj. causes red dot to move left / right. Wish the GEM28 came with the GPS fob... I had to use the GPS fob from my GEM45. I don't remember if the GPS ever synched, as it was not synched within the first 15 minutes when I last looked at it. Since I normally use this mount at my home, if GPS isn't avail, it is not really a problem. I manually entered the Long/Lat into Commander and synched the mount. Once I loaded the latest Commander/ASCOM drivers/software (v7) everything worked without a single problem. Guiding seemed reasonably stable, although the viewing was early in the evening, which at my location is normally a problem. Only time will tell, but I am satisfied with the results. I prefer guiding with PHD2 using mount pulse guide, which eliminates the ST4 guide cable. Slewing the mount and pointing in SkyX was quiet and accurate. The newer RA/Dec gear switch set up is way better than that of the CEM25P with the inaccurate gear tension adjust knobs. Overall the quality and features of iOptron mounts is steadily improving, although not without some issues along the way
This is a great mount for my William Optics Zenithstar 73. It performs very well and has a high quality build. It is a lightweight mount that has strong, quiet motors. I look forward to more clear skies!