Emcan Astro EM31 Pro Review – Lightweight, High-Performance Mount

Emcan Astro EM31 Pro Review.

NOTE:
I reached out to Emcan Astro regarding my intention to purchase the mount,
and indicated that my intention was to provide a review of the equipment once I’d had some time with it.
At this stage, I was planning on utilising the EM31 Pro with a ZWO TC40 that I already owned,
however they assured me their system was superior to the TC40.

I was reluctant to purchase the tripod considering I already had one that would work.
Emcan Astro generously supplied the RP200 tripod leg extensions to me at no cost, in return for the review.

Aside from the RP200 extensions I purchased the mount and all other accessories with my own money.
So, while Emcan Astro did give me a discount on the entire kit (in the form of the extensions being provided for free),
my review is 100% my own opinion based on the time I’ve spent with the mount and accessories since purchase.

BACKGROUND:

At the start of 2024, my only imaging telescope setup was an Askar 65PHQ, Player One Artemis C Pro camera with an OAG and a few accessories/adapters, however my mount was my trusty 2005 vintage Losmandy G11 Gemini that I’d owned for MANY years. Originally purchased in 2005, The G11 was acquired when aperture fever had a solid hold over me, and my spine was in far better condition than it is today…

While the G11 Gemini is a phenomenal mount, it seemed ridiculous that I was pulling nearly 45kg of mount, tripod and counterweights outside, in order to operate my ~6kg astrophotography rig… I went out in search of a mount that would perform as well as the G11, but be far more portable and easy for my damaged spine to move around.

At the time, I thought that my days of aperture fever were behind me, and my neat and tidy little 65mm APO was all the scope I’d ever need, so I only really needed a light weight mount, This being the case, I purchased an Avalon Instruments M-Zero. Fantastic little mount, my whole imaging rig (including the mount and tripod) now weighed around half the G11 mount and tripod.

I was routinely getting 0.5”~0.6” RMS guiding from the G11, and I figured it would be a pretty big stretch to get better than that with the M-Zero… well…Night 2 with the M-Zero, I had an RMS after a number of hours of 0.45”, I’d seen portions of the night at 0.38” and as high as 0.56”, but essentially, equal to or better than the G11 in terms of performance, 1/3rd the weight, beautiful design and construction, very simple to operate. I was in mount nirvana…

And then it happened… Not 5 months later… My brain looked at an image I was making of the Helix Nebula, and I thought… Imagine if you had 2x the aperture, and 2x the focal length… How much better would this be then…

The G11 was too heavy for me to utilize, and the M-Zero did not have the capacity to operate a 5” APO… So.. I was stuck.

If I wanted to move up to a larger APO, I needed to find a different mount.

PREREQUISITES:

1. Light weight.
I did not want the mount to be heavier than the M-Zero. The M-Zero is light at around 12kg for the mount and tripod, and that was really my limit.

2. Amazing performance.
After the G11 and M-Zero providing me ~0.6” RMS or better guiding, I wanted again, to retain at least this level of performance. Remembering that my 65mm APO gave me 2.29”/px resolution, and my new scope was going to provide 1.14”/px, I needed to keep that performance as tight as possible…

3. Beautiful build quality.
This seems silly I guess to some, but after having the G11, a beautiful beast crafted from CNC machined aluminium, anodized black, with brilliant trimmings and ergonomics, and easy to use polar alignment controls, and the M-Zero, Italian made, CNC aluminium all anodized in a beautiful shade of red, again, with incredible attention to detail with regards to all the knobs, fittings, and polar alignment controls. I wanted whatever mount I got next to look and feel of similar quality.

4. Sturdy, especially on a tripod.
I don’t have a pier, my setup is not permanently installed, so I need the mount and tripod to be rigid. My current 65PHQ rig wouldn’t be an issue on any modern mount, but the 5” APO I was purchasing was going to put a small, lightweight tripod through its paces.

5. Different.
This is actually silly, but it’s how I’ve always been… When everyone was running an EQ6R and a newtonian, I was running a G11 with an RC, when everyone moved to fast refractors, I got a Tak Epsilon… When the Redcat 51 became the gold standard of small telescopes, I got an Askar 65PHQ… When I wanted a light weight mount, everyone else was buying ZWO harmonic mounts, I bought the Avalon Instruments M-Zero.. I like to be different… This was going to be the kicker - because the masses are not wrong. The ZWO AM5 would fit almost all my requirements, though I didn’t (and still don’t) like their overall fit and finish. They feel cheap in some aspects, and I did not like this.

DELIBERATION:

So after researching for weeks… Bringing my list of possible mounts from 6 originally, down to just two, I was torn between the ZWO AM5n (which had not been released yet) and the Warpastron WD17. Both of these mounts were harmonic mounts, cost roughly the same, both have very similar specifications… The AM5n had the advantage of the USB and power port in the declination head, which is a brilliant addition, the WD17 was ergonomically reported to be much nicer, the polar alignment controls were smoother and more repeatable, and locking the adjustments once polar alignment was achieved did not shift the alignment, which is important to me, of course, the WD17 was also available to purchase immediately…

I was watching some of Cuiv the lazy geek’s videos about his WD20 mount, figuring the WD17 and WD20 are very similar mounts, and that what held true for the WD20 would likely hold true for the WD17.

Right on the cusp of clicking the “Add to cart” button, I saw Cuiv’s review of a relatively new, unheard of harmonic drive mount from a company called Emcan Astro.

ENTER, THE EMCAN ASTRO EM31 PRO:

The Emcan Astro EM31 Pro mount offers, again, very similar specs to the ZWO AM5n. It boasts the same 15 kg payload capacity without counterweight, and 20kg with 5kg of counterweight, measured at 20cm from the RA axis.. What the specifications do not make immediately obvious, however, is that the EM31 Pro’s declination head is only 80mm from the RA Axis, 10mm less than most other mounts. Meaning that the load you can put in that 200mm distance from the RA axis is actually larger than most other mounts (There is plenty of information online on how to calculate the load capacity based on the distance from the mounts rotational axis by calculating the torque).

Further to the mount having either the same or better specs than the two other mounts competing for my money at the time, I started looking into the mount further…

Their tripod system is very different to the normal (when I say ‘normal’, assume I’m talking about the ZWO equivalent product) carbon fiber tripod. Rather than telescopic legs, the Emcan Astro TC44 tripod system is a series of components, so you can mix and match the parts you need for your particular use case. (More on this later)

Now, normally - I would not purchase something of this sort of cost when there was only one review online, there was only one place I could buy the mount from, that was AliExpress, and there was so little information available online, so I reached out to Emcan Astro, and to my surprise, they responded within a couple of hours, and were able to provide me with some further documentation around the tripod design, they did confirm that the mount would work with the ZWO TC40 tripod, however they assured me that after I’d read the tripod documentation they sent, that I would be better off to purchase their entire system.

Given the review from Cuiv, and the speed and detail of communication I had with Emcan Astro, I decided to put my money where my mouth was, and purchase the mount…

SPECIFICATIONS:

While I largely feel that the specs are the ‘boring’ part - I know as well as anyone that they are important…

So what’s the Emcan Astro EM31 Pro all about?

Mount:
Weight: 4.5kg
Load Capacity: 15kg/20kg with a counterweight.
Latitude adjustment range: 0°~90°, with the fine adjustment allowing for +/-10°
Azimuth adjustment range: +/-8°
DRIVE:
RA: Type 17 1:100 harmonic reducer Nema17 (42mm) Stepper motor with power-off brake
DEC: Type 17 1:100 harmonic reducer with Nema17 (42mm) stepper motor.
Max Slew Speed: 6°/s
Power Supply Requirement: 12V DC 5A, 2.1x5.5 connector.
Power consumption: Tracking 0.3A (tested) Slewing 0.65A (tested)
Zero position: Manual via bubble levels.
Operating Modes: Equatorial, Alt/Az side mounted, Alt/Az top mounted.
Operating Temperatures: -15°C ~ 40°C (5°F ~ 104°F)
Manual Operation: Hand Controller (Supplied)
Control System: OnStep.
Supported Interfaces: ASIAir, ASCOM, INDI
Warranty: 2 years

Tripod:
Flange Interface: 85mm round dovetail joint (double locked)
Leg Diameter: 44mm
Leg carbon fibre wall thickness: 2mm
Leg spread angle: 32°
Folded Length:
- Tripod alone: 620mm
- Tripod with RP200 Extensions: 850mm
- Tripod with RP200 Extensions and AD120 leveling adjusters: 950mm
Setup Height:
- Tripod alone: 530mm
- Tripod with RP200 Extensions: 720mm
- Tripod with RP200 Extensions and AD120 leveling adjusters: 810mm
Weight:
- Tripod alone: 2.5kg
- Tripod with RP200 Extensions: 3.3kg
- Tripod with RP200 Extensions and AD120 leveling adjusters: 4.2kg
Load Capacity: Not specified, but I can tell you - it’s a LOT!

WHAT DID I BUY?:

I purchased the mount and all the tripod components to use the mount in Equatorial mode only. Whilst this is a VERY capable Alt/Az mount also, I do not do visual astronomy, and as such, I didn’t require any of the Alt/Az components.

My order was for the following.
1x Emcan Astro EM31 Pro mount.
1x TC44S Tripod.
1x RP200 Tripod leg extension kit (contains 3 extensions)
1x AD120 Tripod leg leveling adjuster kit (contains 3 leg levelers)
1x EMH150 Pier Extension

The total cost for this setup was AUD$4424 (though I paid $4262, as the RP200 extensions were provided for free, as discussed earlier.)

After payment, the mount arrived from the other side of the planet in under a week.

PRICE COMPARISON:

Similar setups sit at roughly the same price range.
ZWO’s AM5n, with their TC40 tripod and PE200 pier extension: AUD$4518.
Warp Astrons WD17 with the ZWO Tripod and pier combination: AUD$5167

While there are a few cheaper harmonic mount options, I feel like there are tiers to the overall product quality… Something like this.

Top Tier: Rainbow Astro, Warpastron’s WD20
Mid Range: ZWO, Warpastrons WD17, Emcan Astro, iOptron,
Entry: Proxisky/Meowastro, Juwei

So while the Juwei-17, or Proxisky UMI17 have similar weight capacities as the AM5 and EM31 Pro, There are some aspects of their specifications that make me wonder how they are manufacturing a mount for 33% of the price of the other brands… And while I know that making a harmonic mount with off the shelf components is actually much easier and cheaper than building a tradition worm gear driven equatorial mount, I don’t think that you can cut AUD$2500 out of a $4200 product and still be maintaining all the same standards…

It’s safe to say that the Emcan Astro EM31 Pro is quite competitively priced, ending up cheaper than either the ZWO or Warpastron option. Can I say categorically that it is better than either of those options… No, because I don’t have them available to test side by side. What I can say though, is that I get better results from the EM31 Pro, than I got from my Avalon Instruments M-Zero , or my Losmandy G11 Gemini

UNBOXING:

In all my excitement, I did not get any photos of the unboxing process, though I will note that everything was packed brilliantly, in suitably sized, double walled boxes, with extra padding added around all the sensitive components.

DETAILED LOOK:

Upon first setting up the mount and looking at it, I was exceptionally impressed. The mount looked and felt incredibly nice, the machining on all the components was stunning, and the finish of the carbon fiber components was beautiful.

All the knobs and adjustment points for the mount have such low tolerances that there is no wobble or play in any of them, even when loose, everything feels like it’s solidly mated together, or cut from a single piece of metal. It’s really something!

Prior to purchase, I thought the Declination saddle power/usb ports were a ‘nice to have’ feature, but not a deal breaker.. After setting this rig up a few times, and not once worrying about any cable snags, let me assure you, if your prospective new mount does not have a USB connector to control the mount, and a power port in the declination head, pick another mount… This is absolutely a game changer… It makes cable management simple, safe, and reliable - which is super important on harmonic mounts - where the torque is so high that the mount can literally pull power/usb sockets out of the computer/power box if a cable gets snagged.

The USB port on the declination head is just a replication of the USB port on the bottom of the mount, however, the 12V DC port on the declination head is a bi-directional pass through, meaning, you can plug your 12V DC power source into the bottom of the mount, and that will power the mount, and supply 12V at up to 5A through the port on the declination head, allowing you to power computers/cameras/dew control etc… Alternatively, you can run your 12V power directly up to your telescopes power box, and then run a cable from your powerbox to the declination head, supplying 12v DC power to the mount via the declination head port… For me, the latter seems counterintuitive, as there will be a cable running from the ground, up to the telescope which gives opportunity for cable snags, however for someone running something like a stellarmate pro, or PrimaLuceLab Eagle, it may be advantageous to power such devices directly, then power the mount off the device.. For me, I have a small Wanderer Astro power box that is mounted to my telescope, that powers the Mini-PC, Dew heater, and my Camera,

FIRST LIGHT - SETUP:

First light, somehow, happened the night the mount arrived! I installed the OnStep Ascom driver into my Mini-PC, created a new PHD2 profile for the mount, got it all setup outside with the 65PHQ on board… The process of physically setting the mount up is quite simple, though, ingenious at the same time. To get rough polar alignment, you unlock the RA axis bolts, and the mount can be freely moved in altitude, so you simply line the marker up approximately to your latitude, then lock it down… While this seems backwards, this is where the ingenious part of the setup really stands out. Once the Altitude adjustment is ‘locked’ the main adjustment knob is still able to adjust the altitude up and down as much as +/- 10°! This means that once your altitude adjustment is complete - it’s already locked, so there is NO chance of nudging it out of alignment by locking down the adjustment! Perfect.

So I got it roughly aligned to the pole, got my gear mounted up on it and waited for dusk…

Well… that was all I got from the night.

FIRST ISSUE:

For some reason, NINA was unable to do an accurate 3 star polar alignment routine, as the mount would not slew at a reasonable speed - it appeared to be stuck on 20x Sidereal, and there was no way in the driver software that I could find to alter this.. I was not operating the mount with the hand controller, so there was seemingly no way to fix this... So I took it all back inside for further investigation.

Feeling defeated back inside, I plugged it all in (including the hand controller) and noticed the same thing, that the mount was set to 20x Sidereal slewing speed. I changed this on the hand controller, then went back into NINA and initiated a slew - and away the mount went at the full 6°/s - Awesome! So I took the whole rig back outside, fired it up, went to slew to the first alignment point - no perceivable movement in the mount…

After a brief discussion with Emcan Astro - this is a safety feature of the mount, and when it is powered on, its slew speed is set to a slow speed and must be turned up to a higher speed in order to use the mount how you’d expect… This would be fine, if there was an easy way to automate this in software, however, there isn’t…

There are 3 ways to do this.
1. Via the hand controller, though this is impossible if you’re operating the scope from inside your house and it’s out in the yard/observatory, and impractical if you’ve sent your mount to a remote observatory..

2. Via the web interface or mobile app. If you connect your phone to the mounts wifi or bluetooth, you can use the OnStep app to modify the slew speed, or alternatively, use the web interface to do the same. Though you still need to be physically near the mount to achieve this.

3. Using OnStep’s proprietary planetarium application which provides all the controls for the mount… While this is currently the ONLY way to do this semi-remotely/remotely, it still does not feel right in my book, as I don’t want to have to launch an unnecessary piece of software to change one single setting, every single time I start the mount.

Note: if you run a mini router on your astro-rig like many of us do, you can connect the mount to the routers wifi, then access the web interface from your mini-pc. I’m in the process of writing a NINA plugin that can send the required command to the mount via a pre-configured IP Address, however if you are not using a mini-router, this is again, impractical as you have to get close enough to the mount to get a decent WIFI/Bluetooth connection to the mount and then make the change.

FIRST LIGHT - TAKE TWO:

With the knowledge from night one in hand, and a bit better understanding of what I needed to do, setup on night two was much quicker. I got the mount set up, and finally had a chance to use those fancy polar alignment controls that I was talking about earlier.. Not to mention the very smooth Tripod leg adjusters.

The Tripod is solid, sturdy, and once set up and level, I can assure you, this thing is not going to move.
The AD120 Adjusters provide a simple, stable and repeatable way to adjust the tripods level, without loosening tripod legs while your mount sits above, this is a direct, risk free method of adjusting the tripod, and I for one, love it..

Without doubt - the best polar alignment adjustment controls I’ve ever used.. I’ve owned a lot of mounts - and NONE of them feel as smooth as this thing does, nor do they have adjustment ranges that are so fine. So in altitude, I find that 180° rotation of the adjustment knob gets me about 20 arcmin of adjustment. This makes it SO easy to make either large adjustments, because if NINA tells me I’m 1° too high, I just turn the knob 1.5 rotations counterclockwise, and I’m within a few arcseconds… Azimuth adjustment is similarly, exceptionally smooth and repeatable, with every half turn of the knob resulting in 10 arcminute of adjustment. 3 full rotations of the knob getting near on exactly 1°

The process of polar alignment took me 3 minutes to go from a raw setup (admittedly, I was only 20 arcmin off in Azimuth and 50 arcmin off in Altitude, because I know where the pole is from the spot I usually set up my mount), but it was under 1 arcminute is 3 minutes of adjustment…

With the Askar 120APO atop the EM31 Pro, the EMH150 is a necessary part of the kit. If I was only running the 65PHQ I doubt it would have been required. If I had a gripe, I would say that the EMH150 would have been nicer if it were 200mm high, not 150... I have conveyed this to Emcan Astro, so perhaps they will release a taller pier extension in the future.

Unfortunately for me, it was a 96% full moon… So what to shoot…

Funnily enough - my new scope had arrived this very same day, so I figured I’d shoot the moon… I slewed the mount to the moon, and to my surprise, the mount landed the moon just off center on my camera sensor. I fired off a single 1/125th frame… This seemed like a reasonable test for a new 120mm APO telescope, but it was no test for the mount…

I knew under full moon conditions, I was not going to be able to go for nebulae or galaxies, as the sky was far too bright. So I slewed to NGC-104 (47 Tucanae), a lovely bright globular cluster near the Small Magellanic Cloud, and was able to get 127*2 minute subs before clouds eventually called the night to an end.

I hear you all asking ‘HOW WAS THE GUIDING??’

Guiding was spectacular. I started with the usual guide settings that you’d see for a harmonic mount, exposing for 0.5s, 40% RA aggression, 30% DEC aggression, 0.19px minimum move on RA and 0.26px on DEC. Max duration for both axis was set at 500ms.

I enjoyed a total RMS of 0.49” over the space of 4 hours.
To me, this is incredible, considering I had a 120mm APO, with a camera, filter drawer, off axis guider, mini-pc, power distribution system, EAF etc.. totaling around 9.5kg of equipment hanging off the side of the mount with no counterweights what so ever.

The entire night was hassle free, and required no intervention from me after the initial tweaking in guiding to smooth things out nicely.

SUBSEQUENT SESSIONS:

Since the initial first light, I’ve had the rig outside a number of times, and even run a full night of unattended imaging, with two meridian crossings involved, and so far, I’ve had no concerns whatsoever.

Firstly, I did a session on M20 for 1.1hrs in Ha/OIII before cloud ended my evening.

The next night out, I wanted to add some RGB to the M20, and also have a crack at my first galaxy in a long time…

I had the mount slew to M20, and I collected 1.5hrs of RGB data on that, then flipping back to the East to shoot NGC-253 in RGB for 3hrs - completely uneventful night, in that I did not have to intervene once, I just told NINA the two targets I wanted to shoot, told it to go about its business, and I went outside to pack it up once it was done. With guiding staying between 0.45” and 0.57” RMS, I can say that all 4.5hrs of data was 100% usable, with not a single dropped frame due to guiding, despite a reasonable breeze that particular night.

I was able to back that up again two nights later with another 2hrs on NGC-253. Again, uneventful evening..

A week later, I had the best clear night I’ve seen in a long time..

By far the best night I had with it was October 4th, Setting up at 6pm, and packing it all up at 4:15 as the sun started to brighten the eastern sky… I collected 6hrs on NGC-55 and caught my first glimpse of the Orion Nebula since the last time I imaged in in 2009, collecting just over 2hrs on that. That night I slewed East at 6:30pm to image NGC-55, the mount executed a meridian flip a little before midnight, and at 1:30am, the mount executed another flip back to the East to point at M42… All this, again, unattended, I kept an eye on it all from inside using my Wyze camera and remote desktop to ensure things were going as planned… but again, nothing eventful, nothing out of the ordinary.

VERDICT: BUY ONE!

Whilst it sounds a little boring, and, it kind of is… Testing a new mount is very rarely about ‘What cool things does it do?’ or ‘what things does it do that really grabs your attention?’, however, when reviewing a mount, I think the biggest compliment that you can give it is saying you don’t notice it… For me, aside from a few software/settings issues on night one, The fact that since then, I’ve been able to just - set the mount up, painlessly get it polar aligned then tell NINA to collect data, and walk away, tells me how amazing this little mount is.

I would not hesitate for a moment to recommend this mount to anyone looking to step into the world of harmonic mounts, or someone looking for their first serious mount…

It has been a pleasure to use, straight forward, no fussing about… Once you get the process of getting it set up and running, it's simply a matter of pointing it at your target, and trusting the mount to do its job, which it does VERY well…

The mount represents outstanding value for money, coming in as one of the cheapest harmonic mounts available in my country, with only the Juwei-17, and Proxisky UMI17 mounts coming in at lower prices… Both of which I have seen reports of mechanical and electrical failures (though, reportedly, quickly resolved by the manufacturers)

The Juwei, Proxisky, Warpastron and Emcan Astro mounts all share the same control system, OnStep, which is quite fine overall, and like all telescope control systems, once you understand their idiosyncrasies, are perfectly suitable…

Having used Skywatchers Synscan, then EQMod, then Losmandys ‘Gemini’ system, Avalon Instruments ‘StarGO’ and now OnStep, I will say none of them is inherently better than the others… Actually, you know what, the Losmandy Gemini system was probably the best for 100% computer control, the driver was phenomenal, and the mount operated exactly as you told it to with very little in the way of ‘unexpected behavior’, but as for the rest, OnStep, Synscan, EQMod, StarGo, and I expect, the ZWO control software, I feel like they are all very much the same - once you understand them, there is no issues at all.