Telescope-Equatorial Mounts-iOptron GEM28 German Equatorial Mount with LiteRoc 1.75″ Tripod

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1. Rob B. Verified Buyer – 28 September 2021

   I bought this as an upgrade from my CG-4 mount. Like many, I began with visual and crept into astrophotography. I’ve had my GEM28 out a handful of times now. I love the iPolar, even if it means I have to bring my laptop out with me. My experience with that is aligning declination first, and being slightly ‘off’ so that when I tighten the knob it m

   oves into the position I want. Tightening the knob will move the crosshairs a bit, as will tightening the azimuth securing bolts on both sides. I normally loosen those just beyond ‘snug’ and get as close as I can. Then I snug them, and this allows me to still make adjustments. Further tightening the bolts doesn’t seem to have a large impact at this point, and afterwards there is still enough play to make fine adjustments.

   The hand controller is easy to use. I invested in some Velcro to attach it to the tripod. I was setting it in the tray and my clumsiness would often lead me to bumping the mount when reaching for it. I carry the mount, tripod, and counterweight outside assembled together, up and down a full flight up steps. It’s a little heavier than doing the same with my CG-4, but it also supports more weight. The levers to tighten the tripod legs leave a little to be desired. In order for them to not be sticking out, I feel as if I have to over-tighten them. I haven’t heard anything crack yet. I only need the tripod extended when using it in my suburban yard, and It’s sturdy enough with my 12lbs of load on it.

   The one star or two star alignments didn’t get me as close as I was expecting. The three star alignment did work much better. I figured out that this was due to something called ‘cone error’ with my optical tube and it’s mounting hardware. I physically corrected that and now a simple one star alignment gets everything very close to center in my eyepiece. I have used this for astrophotography a few times, even though my telescope isn’t designed for it! I have a 102mm f10 achromatic refractor with a 60mm f4 guide scope. Using an ASI 120MM-mini to guide with and my DSLR to image, I was able to consistently get 4 minute exposures with nice round stars. I have tested it at 5, 7, and 10 minutes, with 7 minutes being where the stars begin to become oval shaped. I might be able to tweak guiding to improve that, but for a newbie like me, the mount seems to do very well.

   There is one thing that I find curious though. I have the correct battery in the handset, yet the internal clock still runs a bit slow by variable amounts. Sometimes it’s 3 minutes off, others just a minute. It’s not difficult to synchronize the time while I have the laptop out for polar alignment. It does baffle me why it doesn’t keep accurate time though.

   All in all, I am very pleased with this purchase. I also own a SkyGuider Pro and thoroughly enjoy that. Its quality is what lead me to this mount. I expect that when my need for larger capacity arrives, I will once again go with an iOptron mount.