BBO Astronomy

Better Late than Never

My New Mount

After 11 years of using a Losmandy G11 EQ mount it was time for a change. The Losmandy is a very stable and reliable mount for astrophotography and many imagers use them. For me, it just became my weakest part of my system especially after upgrading my imaging camera to the 20MP ZWO ASI183mm Pro. The Losmandy had intermittent times of great guiding at .30 arc sec., but other times it could be over 1.5 arc sec. I did all I could to tweak the mount with better worm gears and bearings but I just wanted something I didn't need to fiddle with.

So in the summer of 2021, I decided to do more research and track down a new mount within my limited budget. I wanted a mount with payload capabilities similar to my G-11 even though I'm using a 20lb imaging train. I am always wanting a larger scope. The summer of 2021 wasn't the best time to look for something new, with covid 19 still affecting supply chains for anything astronomy related. If I found a mount I was interested in, could I actually get my hands on it? My dream mount was the Italian made 10micron GM1000HPS, but at $13.000+ that was out of the question.

I started researching the Sky Watcher EQ-8. At around $5000.00 it looked promising. The reviews seemed good with the exception of USB port flaws, but I figured I could work around them. Now I had to find one. I scoured the internet with no luck. Talking to a few Canadian dealers, they told me that they didn't expect any new stock until summer 2022. The 3rd mount on my list was the iOptron CEM 70. It had favorable reviews and was in my price range. The CEM 70 had a lot of great features I wanted. One thing I didn't need was a tripod, with the mount sitting in an observatory on a permanent pier. So back to searching online. Behold, I found one, the CEM 70G, with no tripod. It was in stock and ready for immediate shipping. The G version of this mount has its own built-in polar alignment scope and guide scope with camera. One day later I received my packages from Ontario Telescope: The mount, with its own carrying case, the counter weight, and the pier extension kit, as recommended by the owner Steve.

Installing the mount on the existing pier was quite simple with a part from the pier extension kit. I had to drill a few holes and it was good to go. All I had to do now was to polar align the mount. The CEM 70G has a built-in polar alignment scope and camera, but it needed to be calibrated before use according to the manual. Since I already had a QHY Pole master alignment camera, I decided to go with it since it didn't need calibrating and I was familiar with its use and accuracy. The CEM 70G has a payload of 70lbs, so my 20lb imaging system is nothing for it. The feature I like most about this mount is its internal cabling system and built-in USB-3 hub. No more dangling wires. I plug in 1 USB and 12v power cable to the base of the mount and there are connectors at the base of the telescope. Nice and neat and no wire snags.

After the mount was polar aligned it was ready to go. I did a 2 star alignment then slewed to my first object, M57. It was dead centre, perfect. To this date I haven't needed to do another star alignment. The auto guiding on this mount has been exceptional for me, .25 - .65 arc sec. I've seen a great improvement in my images, with smaller and rounder stars. For the first month of using this mount, I used the hand controller. With the built in GPS system, it automatically calculated the proper time and location. All the functions of the mount were at my fingertips. But, after about 2 months, the hand controller lost its brains. Its internal battery had failed. The tech department at iOptron responded to my email within a few hours with a PDF on how to replace it. After doing so, the hand controller worked well again.

      Recently I decided to change how I operate the mount. Everything is now computer controlled and operated from my PC in the observatory or from the house. This opens up many possibilities, like automatically running a full night of imaging while I'm sleeping. I haven't tried this yet because I still like being out in the Observatory keeping an eye on things.

            Overall I highly recommend this mount. I've been using the CEM70G in my observatory for 16 months. It does what its supposed to do very well. Hopefully one day, I'll be able to test it with a much heavier telescope.

P.S. Even though I have many opinions on the equipment I own, this is my first actual written review. I hope to have more in the future. (All of these opinions and comments are my own)

Glen Pidsadnick