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FLO sent me this beast of a mount for review, and after a few months use I've finished said review. If you don't want to read, then scroll to the bottom to see the video. If not, let's go.
From the top, the dual type Vixen/Losemandy type puck, and at the back of mine it had 3 5521 type power ports for powering equipment, and 3 USB ports (2 powered) for connecting to the internal USB hub network. Whilst I didn't exactly use this network, it's still very handy to use, especially being on the puck - it means you don't have to worry about any slack on your cables and they won't pull. A handy feature. The power ports seem to be of a different type to 99% other astronomy hardware though, which means you'd need to get different connectors, a major inconvenience which still will make itself known later.
The mount includes an iPolar system, which is absolutely awesome. Sure the UI looks like it's straight out of Microsoft Paint but it's certainly function over form as it's quick and uses plate solving to align. This means you can polar align even with a semi-obstructed view to the pole. It's powered by a USB2-B port at the back of the mount with no need for external power. There is no manual polar scope on the mount so a computer is a must for polar alignment.
The carry capacity of 31.8kg is a hefty amount, though it's advised to not exceed 21kg for astrophotography. I never loaded it up with this much equipment however the sheer build quality and performance of this mount leads me to have no concerns whatsoever about using that much weight, or even all the weight. It's always advised to use underneath the stated maximum capacity anyway.
The altitude adjustment knob is a hefty coarse worm gear style affair. Embossed with the iOptron logo. It's a nice way of adjusting, especially when coming from GEM mounts where you have to undo/do up two individual bolts. However on my mount it was let down by an abhorrent squeak it made when raising it whilst the mount was loaded up. When going down in altitude sometimes the gear would jump a bit and let the mount down even further than I wanted. Azimuth adjustment was fluid and great.
The control panel includes its power port, power switch, hand controller port, ST-4 port and the USB port. The USB port can be used to control the mount via computers, and is also the other end of the internal USB network. It is USB2-B.
A major issue I found was the power port. It wasn't the standard type DC centre-positive tip style that all my other astro equipment used. IT's also a standard female type port, whereas I would've liked to have seen a screw type connector for this price point. But yes, the biggest gripe was the different style port, which meant I couldn't power it using my power box (without getting more cables), and had to use the supplied plug.
The carry case is a substantial and very sturdy box. It's foam cutout and very tight in holding the equipment. All but the counterweight goes into this box and I believe it could really survive quite a harsh fall. It's very well built.
Slewing with the CEM70 was quick and fluid, it was also quieter than I was anticipating for such a large bit of machinery. Using its own dedicated software through the laptop was intuitive and there was little to no learning curve. The axis clutches, whilst using a small switch, feel solid and substantial with a nice meaty clunk when engaged. One lock position is the EQ Home position which makes life a lot easier.
When guiding, I was regularly getting values of 0.4-0.6" total error. This enabled me to take extremely long exposures if I so desired, though I mainly did 5 minutes, I was able to do 10 under testing. Unguided (just sidereal tracking) I was only able to achieve 2 minutes before trailing was found with my Evostar 80ED (reduced to 510mm) and ASI 071mc Pro. Now in full admittance the mount was unbalanced as the Evostar package was too light for the mount.
The counterweight, if moved too high up the bar, will strike the body. So you would need to buy a lighter weight if you wanted to balance a lighter load on the CEM70.
Also when attaching it to a tripod or a tri-pier, you do need to bolt down 2 spring loaded bolts down with the supplied allen key. Now this is a bit fiddly and adds several minutes to the setup and tear down times. Though I suspect iOptron made this mount with a permanent setup in mind so if you're putting this into an observatory then this won't be a problem. For me, who setup and torn down the rig each night when using it, became a bit of a chore.
Overall I found the CEM70 to be an extremely capable mount with a lot of features. Whilst there are niggles that detracted from the user experience; the altitude gear squeak and the non standard power ports. Other features improved the quality of life and user experience enough to vastly outweigh the drawbacks. The iPolar system is particularly capable and excellent, the carry capacity, build quality also and guided performance, as well as the internal USB hub.
I think this would be a nice investment if you were looking to mount larger scopes on, or decking out an observatory. I can't afford one but if I was making my own permanent setup I would severely consider buying one.
If you're interested you can find more information at the links below (if you did buy through these links, I'd earn a few pennies to help support these reviews).
iOptron CEM70 w/o iGuider: https://bit.ly/CEM70
iOptron CEM70 w/ iGuider: https://bit.ly/CEM70iGuide
iOptron Tri-Pier: https://bit.ly/CEM-Tripier
Thanks for reading everyone. What are your thoughts about this mount? I hope my review has been helpful for you clear skies all, keep looking up and keep them cameras clicking.
By The Admiral
I recently took delivery of this mount, having until now only used an Alt-Az mount for imaging. So this is a whole new experience, and as such I’m not really in a position to give a meaningful performance review. Nevertheless, here are my first thoughts.
I wanted a mount that could be set up for each session, and light enough to allow my ageing frame to be able to carry it from inside the house to outside. It also had to be able to successfully carry a load currently around 6-7kg without complaint. So this is what attracted me to the GEM45. I bought the version with the case and tripod, non-EC. I don’t guide it as yet, so I can’t quote chapter and verse on its guiding performance.
Here's the set up raring to go! I've left the tripod trousers on!
It seems a solidly built, well finished, precision machine, unlike what one would expect from a mass-produced object. The axes move smoothly and I haven’t noticed significant backlash either by ‘free play’ or other than instant response to commands when lining up objects. However nice the looks, performance is everything of course, though it does give confidence.
The first thing I needed to do was to swap the latitude adjustment from the low position to the high position, as I live in the UK. It is worth noting that for where I live, ~51° N, I need to wind back the altitude to ~40° with the altitude adjuster (not re-set the setting from high to low, fortunately), each time I need to get the mount into the foam cut-out of the case.
Initially I had trouble locating the bolts with which to bolt the mount onto the tripod, the Azi Locking Screws. Thanks to FLO that was simply resolved, but I found that one of the bolts was slightly bent, enough to bind a bit in the thread, again resolved by the excellent services of FLO. Also, these bolts are meant to be used with the provided washers, but only one could be located. These are little perishers, as it’s easy to drop them when assembling the mount, as I discovered. My wife’s eagle eyes managed to spot it on the patio; try doing that in the dark! It’s a pity that the bolts don’t have a winged- or star-head for finger tightening to make life easier with repeated setting up, but there isn’t room beside the mount to allow that.
The bolt shown here is a make-shift arrangement and is not the proper bolt and washer.
The same could be said for the Lat Locking Screws, since they have to be slackened off and re-tightened before and after setting up/Polar aligning. However, these could reasonably be replaced with hand operated bolts, rather than rely on the Allen key, as there is ample room.
A note re. the tripod, is that it has an alloy top plate and I do wonder how resilient it will be to the repeated attachment of the mount. However, I also bought the Mini-Pier and the threads on this are inserts pressed into the alloy and look to be made of a more bolt friendly material. I plan to leave the Mini-Pier on the tripod.
As I said I don’t guide so I can’t offer any figures. So the best I can do is provide some subs from my recent tests. You’ll need to bear with me on this as I’ve not many examples to date. My first examples are of M3 showing different sub durations of 90s, 120s and 150s. Unfortunately I was having trouble with my optical train and have got out of shape stars towards the edges anyway so that may confuse. Here they are for what they are worth:
My second offering is a sub from an attempt at M81 shot at 90 seconds:
The full image is posted here https://stargazerslounge.com/topic/352345-m81-m82-with-gem45-unguided/.
In summary then:
The iPolar is a doddle to use, though does need a laptop to be set up for the alignment process, but that can be put away afterwards. Far better than kneeling on the floor and craning one’s neck.
I’ve found tracking to be good enough for me up to about 1½ minutes, though possibly beyond that to 2 minutes or more, without guiding, with a FL of ~560mm and load between 6-7kg. Depends on how purist one wants to be about ‘round stars’.
It’s quiet whilst tracking but slewing is by no means silent. I’m always concerned about disturbing neighbours so perhaps I’m being unduly critical. It’s quite difficult to judge how loud these things are in the middle of the night when you are standing next to the source. Then again, I’ve not used other mounts to compare it with.
The hand controller seems fairly logical to use.
Assuming I’m setting up everything correctly, I’ve found that the homing in on alignment stars to be somewhat ‘out’, and have always needed a significant correction to align. I do a 3-star align and I find this to be the case for each star. However, when I come to align on my target I found that it centred the object very well. May be I have significant cone error which will only be corrected for after the 3rd align, if I understand correctly.
The need to reset the altitude setting to around 40° in order to replace it into the case.
Fiddly washers beneath the mounting bolts which are easy to lose. A touch of grease might help them to be retained by the bolt.
Having to use the Allen key on the Lat Locking Screws.
When aligning, the stars offered are in magnitude order, which from one point of view is logical, but is a bit of a pain when one wants to find particular stars. It would be good to be able to change your preference on star order.
That's it for now, and I hope that it's been of some use.
I've been processing this image for quite a long now.
I started acquiring data the last season when I only managed to shoot 3 panels with the Canon 6D through the Esprit 80 for a total of ~7h.
This season I restarted and I added more data and covered a wider area. So a mix of portrait and landscape panels were planned and shot with the same scope and camera. Now every pixel represents at least 3-4h of integration, some have more.
All the above were shot from Bortle 2-3 sites where I traveled sometimes even for an hour of exposure.
To the RGB data I added 17.5h of Ha, same story with the panels. Some were oriented N-S, others E-W. These were shot with the SW 72ED and the ASI1600 from home and Bortle ~7.
Then I figured out I still had time and I planned and shot 9 more panels of luminance with the 72ED and ASI1600, each consisting of 1h of exposure.
I combined all of these into an image, processed it and for the Orion nebula and Running Man nebula I also blended some data I shot last season with the 130PDS and ASI1600 from home.
Below it's my first final version of all data combined. You can watch it in full resolution on astrobin: https://www.astrobin.com/full/jni0w8/ or Flickr: https://flic.kr/p/2iBGUXq