iOptron CEM120 - any opinions?

[gorann]

Friends,

I am thinking about getting a sturdy mount (ca 50 kg payload) so I can put double rigs or larger SCTs on it and with a bit more precision than my EQ8, and I have been impressed by the combination of price (relatively "low") and specifications of the iOptron CEM120, particularly the version with encoders (4600 GBP). It is stated to have periodic tracking error of <0.15 arcsec RMS, which I think puts it up there among the very best mounts (all of which are more expensive). You can read about it here:

https://www.altairastro.com/iOptron-CEM120-EC-Advanced-GOTO-Equatorial-Mount.html

Does anyone have any thoughts, or even better, any experience with this mount?

Cheers

Göran

Edited January 29, 2018 by gorann

[tocster]

There are a few threads on cloudynights about it - worth checking out.  I would not want to be an earlier adopter just yet though.

[gorann]

2 minutes ago, tocster said:

There are a few threads on cloudynights about it - worth checking out.  I would not want to be an earlier adopter just yet though.

I had a quick look there but did not see any threads but I look again, Thanks!

[gorann]

So, I had anther look at Cloudy Nights and it looks like people are, like me, waiting for anyone to push the pay button, test it, and post a report. Also, everyone seem to agree that if this mount holds what is promised, it is by far the best you could get for that amount of money and would be a game changer.

Edited January 30, 2018 by gorann

[r3i]

Don't know whether you came across this but there is one CN thread from somebody who owns one:  https://www.cloudynights.com/topic/606306-ioptron-cem-120ec/

[gorann]

7 hours ago, r3i said:

Don't know whether you came across this but there is one CN thread from somebody who owns one:  https://www.cloudynights.com/topic/606306-ioptron-cem-120ec/

No, had not seen it so a big thank you Mike! Seems to be an outstanding mount. Just hope the QC is good so that all their mounts will perform like that.

[lux eterna]

@gorann Hej Göran,

Are you planning for imaging without a guidescope ? As long as you guide, I would say the periodic error is not that critical. And the payload capacity for your current mount is the same as the cem-120. Have I missed something, or maybe you will use both mounts simultaneously ?

Ragnar

[gorann]

Just now, lux eterna said:

@gorann Hej Göran,

Are you planning for imaging without a guidescope ? As long as you guide, I would say the periodic error is not that critical. And the payload capacity for your current mount is the same as the cem-120. Have I missed something, or maybe you will use both mounts simultaneously ?

Ragnar

Like all EQ8 mine is suffering from backlash and many nights I have trouble getting below 1"/pixel with guiding (accidentally I have been down to 0.5" which is what I ideally should have with my 5" refractor). It may or may not be related to the backlash and I should probably spend more time trouble shooting. The CEM120 just seem to be a rather fantastic mount and therefore tempting....

[Davey-T]

Ioptron have introduced several " game changing " mounts over the years, I have one myself, some have survived to Mk2 versions some have disappeared, the main problem over the years has ben quality control, so one owner says it's a fantastic mount and others haven't got a good word to say about it.

Frankly if you want to spend a lot of money on a mount with good load capacity and guaranteed to work I'd buy a Mesu.

Dave

 

[tomato]

I have to echo Davey-T's advice, for another £700 or so you can have a Mesu, a proven high capacity, precise mount, which has a wealth of users and hence good community support.

I remember similar discussions when the CEM60 came out, not sure how it turned out in the end, as it doesn't seem to be discussed much on SGL? 

[DaveS]

I would agree with Dave regarding the Mesu, unless you want to spend a stupid amount on a DDM85 Std .

[Davey-T]

Also this new contender.

Dave

 

[pete_l]

Yes. I'm watching the "fun" on CN with interest. If this mount can deliver on its claims then the version with the encoders looks veeeeeery desirable. But it is a big "if".

Though there seems to be a huge amount of hostility from owners of established high-end mounts (even though none of them have ever even seen one of these mounts yet) who just "know" that it can't be any good. Who will turn out to be vindicated? I'll wait for the real-world experiences and honest test results from users who know what they're doing before making any judgements or decisions.

[Astrobug]

This mount is one to follow.

[cotak]

It's no longer a question if the cem120ec delivers what was speced. Been shown a few times it does meet or exceed the established mounts performance. Some have even stated it's better than any of the more expensive American products based on ownership experience.

 

There are plenty of troublesome copies of the American brands. The supporters for those brands have a blind spot for all the times those are reported.

 

As for mesu, the design does have a lot of adventages. However, I think that for a lot of people the encoders taking away the impact of unstable skies will result in less question about if guiding is working or can be improved.

Edited January 8, 2019 by cotak

[RayD]

I have the CEM120 EC and it is very well built, well specced and potential for superb performance.  There were a couple of firmware issues (a random slew) which has been addressed, but a real pleasure to use.

I've done an introduction video and will shortly be posting an update video showing connecting, updating firmware and running in anger.

[Neil27]

On 05/02/2018 at 12:42, tomato said:

I have to echo Davey-T's advice, for another £700 or so you can have a Mesu, a proven high capacity, precise mount, which has a wealth of users and hence good community support.

I remember similar discussions when the CEM60 came out, not sure how it turned out in the end, as it doesn't seem to be discussed much on SGL? 

More like another £1300, by the time you factor in losmandy saddle and x2 10kg counterweights for the MESU, items that are included with the CEM 120.

For me that’s nearly worth an Esprit 100mm in savings, or 500 kg of midget gems which ever tickles your fancy! ?

[JamesF]

I'm struggling to get my head around the idea of half a tonne of midget gems.

James

[ajohnson]

OK Late to the party but I found the thread while looking for some technical data. I have a base model CEM120, no encoders and the older USB2 hub. I bought RVO's ex display model early in 2020 and have it mounted on the Tri-Pier 360 as I tend to move it around because my garden can be nightmare for a good observing spot LED street light one side and two neighbours who are competing on who can grow the tallest tree or install the brightest and most sensitive flood lights. I installed the iOptron iPolar as this seemed the best way to get it polar aligned.

  In terms of metal / build quality it's an excellent mount, very accurate and not phased even when I put my 12" Newt on the saddle for an imaging session. The through mount cable system is neat, you can plug power and USB cable into the unmoving centre section and this is all fed to the saddle where (on my version) I have 4 x USB2 1 x USB 3 and a load of power outlets on the saddle, the theory being no matter where you point it you are not dragging any cables.

On the down side the electronic connectors are not the best, heavy USB cables drop out of the connection hub (USB2, iPolar are particularly weak but the USB3 is a good fit), easily fixed with some cable clips but quality control on the cable management system was poor on my version. The USB 2 connector between the connect points to the iPolar had a bent connection pin on arrival and the multi-voltage 5A power supply to the let side of the saddle wasn't even plugged at the saddle end, no chance of powering your DSLR or high power camera. All that fixed I settled down to some imaging.

All has been well until about 2 months ago, first the iPolar stopped working then one, followed by another of the USB hub ports has failed, as of last weekend none work. I am ordering a replacement hub from FLO, but the iPolar is heading for the scrap bin. Dead after 3 years is not good, for the price of a replacement I can get 20 years subscription to SharpCap Pro and use the Polar align feature (which seems more accurate). I did consider upgrading the saddle to the new USB3 spec but I'm having a crisis of confidence in iOptron at the moment so I am just going to replace the board with the USB2 Hub. Sorely tempted to invest in a Pegasus Astro Advance Power box but the car had a full set of tyres, pads and a service this month so it will wait.

[scotty38]

Nice setup and for free you could use NINA and its TPPA plugin for polar alignment. You don't even need to be able to see Polaris so if one of those trees is in the way then no bother.....

[ajohnson]

Thanks for the tip, it's sounds like it's worth another look. I don't just use SharpCap for Polar alignment, it works well with the mount and camera when running Planetary or Solar Imaging, certainly as well as Firecapture if not better in some aspects.  The camera / exposure analysis is also handy. But it's a moving target I have had a look at NINA and did like what I saw but having been a long time APT user and having renewed my licence for a year I wasn't looking to change just yet. Ask me again in a few months APT and NINA are always adding new features I may have have a different answer by then.

 

[ajohnson]

Harrumph! It now seems the USB3 port is being twitchy and only recognising the camera as USB2 then disconnecting. I'm dropping using the CMS hub on the CEM120 and putting in a Pegasus power box, which I can transfer to my other mount. Not a good result overall. It' may be that iOptron have sorted this out with the newer USB3 Saddle hub but that's £310 and 4-6 weeks lead time + Vs £260 delivered tomorrow. So were down to only using the built in wiring for power distribution where needed. Still the mount itself (all the metal bits) is still a solid performer in terms of stability and tracking. In the end an external box that I can control all of my devices with (including dew heaters) via software and upgrade would always eventually win out over an essentially 'dumb' USB hub.