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Three Simple iOptron Improvements

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Three Simple iOptron Improvements

Michael A. Covington

Michael Covington is the author of Digital SLR Astrophotography and observes clouds, and sometimes celestial objects, from Athens, Georgia.

In what follows I want to tell you about three things I've done to improve my early-model iOptron GEM45 mount. With a bit of adapting, you can apply the same ideas to many other mounts, both iOptron and other brands.

1. Better saddle knobs

Fig. 1: Saddle knobs made from bolts and wing nuts. Note also added declination index mark.

After finding the original iOptron saddle knobs hard to turn, and even experimenting with larger knobs from an industrial supplier, I figured out what I actually needed to do: make my own out of bolts, wing nuts, and ordinary nuts. Because the GEM45 saddle has been through several engineering changes, I'm not going to give exact specifications; instead, remove one of your existing knobs, go to a hardware store, and see what you can put together to substitute for it.

Fig. 2: A hex-socket-head bolt, a wing nut, and two ordinary nuts make a good saddle knob.

Mine had M4 metric threads, and I was able to build the new knobs around hex-socket-head bolts that take the same hex wrench as the mount uses for polar axis adjustment. Now I can tighten and loosen them by hand and also use the wrench if they get stuck. After confirming sizes, I put a dab of epoxy on the threads to hold the nuts onto the bolt.

2. Index marks

Unlike Celestron mounts, iOptron mounts don't have index marks to show zero position. That leads us to do various tricks with bubble levels and the "Search Zero Position" electronic function on mounts that have it.

But index marks are easy to make. I used white-on-black tape from a Brother labelmaker with just the letter I printed in the middle of each piece. You can see the added declination marks in Fig. 1 above, and the R.A. marks in Fig. 3 below. They aren't perfect, but neither are the index marks on any other mount; they certainly make it easy to get close to zero position quickly, and to confirm that you've returned to it at the end of a session.

Fig. 3: Added index marks for right ascension. (For dec. index marks, see Fig. 1.)

3. User-friendly labeling

Good labels on scientific equipment make it easier to use and prevent mistakes. And if they make it looks a bit less elegant, a bit less like fine furniture and more like a piece of laboratory equipment — well, that's what it is!

Fig. 4: Added labels prevent mistakes and make equipment easier to use.

With that in mind, I've added several labels to my GEM45 to indicate what I normally plug into each socket. Besides what you see in the picture, I added, elsewhere, a label with my name, cell phone number, and e-mail address, and another saying "Delicate equipment — iOptron GEM45 mount — read instructions before moving or handling," just in case someone else, perhaps a non-astronomer, has to handle my mount in an emergency. These were made with a Brother labelmaker that was connected to a PC and equipped to make larger labels.

  • eros312, rekokich, Miker K and 10 others like this


The index marks are genius. Never even thought of that. Going to see about making some on my CEM60

    • Michael Covington likes this

I put an ADM saddle on my Ioptron GEM28. A really good modification.


There are a few things i don't like about the mount.

1. It didn't have a GPS. I had to buy one for $125.

2. The way the mount attaches to the tripod head. It uses two small  "Azi locking screws" that you can tighten only with an Allen wrench. This is not easy to do in the dark and those screws would be easily lost in the grass. And the Latitude Locking Lever is in the way on the right side. 

3. Unlike some mounts, the LED for the polar scope needs to be connected to the mount head with the cable provided.

4. The manual, which I had to print, can be confusing and does not always clearly define the terms. For example, I couldn't find anywhere where it defines "zero position, " which some systems call home position. Usually, this is where the scope is pointed due North and the counterweight shaft is down and centered. But the manual never clearly states this, as far as I could tell..

5. The GoToNova hand controller is not always intuitive for me and takes some time getting used to.


On the plus side, the mount is very quiet, compared to my Orion Sirius, which sounded like a bucket of bolts. After only using it once when I could not see Polaris and so guessed at an approximate alignment Even so, it appeared to be tracking accurately. And the optional case is sturdy and very nice. The 1.5" tripod legs are a bit weak. Be sure to get the tripod with  thicker legs - 1.75 or 2", I forget. 

It is mostly built with CNC aluminum, not like the cast metal of the Sirius it replaced.


Overall, despite some foibles, I am generally pleased with the GEM28, but haven't used it enough to know whether or not I love it.

    • Michael Covington likes this

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