iOptron HEM27 Mount overview - iOptron Harmonic Drive Mount HEM 27 EC

We have a look at iOptron's latest mount: the HEM27 & HEM 27 EC Harmonic Drive Mounts. They do away with cumbersome counterweights and shafts: Mount head: 3.7kg - Payload Capability: 13.5kg! These light weight, high payload tiny titans will deliver an astronomy experience like never before.
Find them in stock on our website: proastroz.com
HEM27 Mounts:
proastroz.com/...
Clear Skies!

[@dovber90]

Great review. Exactly what I was looking for. Do you know if its compatible with the asiair pro?

[@proastroz5759]

Thanks for the comment :) Yes ASIAIR confirmed working with the controller's USB port. Connecting to the mount port will probably require connection through USB Hub like it presently done for other mounts - not yet tested.

[@aerozg]

Very interesting. It's almost 2kg lighter than the AM5 and reduces the amount of cables necessary for imaging. The basic version is about €370 cheaper than AM5. It can even handle the C11 for visual astronomy. Apparently they also have other models (with and without high precision encoder) in the pipeline with lower and higher payloads, e.g., 15 lbs and 47 lbs without a counterweight used, to be released in August. Exciting times!

[@bensloane9205]

Good review. Thanks.

[@AstroCrescentDIY]

Nice review of the mount 👍🏼.

[@AstroSoundscape]

Looks a nice piece of kit good video

[@karlderhammer5628]

Nice mount, but having to use a hex wrench in the cold and in the dark is a nonstarter for me. What WERE they thinking?

[@bobwilson8838]

Start setting up before dark. Use a headlight white or red light. You don't need to spend much time using the wrench. This is a hobby all hobbies have some challenges to them. The benefits of the mount far outweigh a few inconveniences.

[@entropytango5348]

A nice review on a great little mount, Unsure what happens if your power fails and you need to move an axis (probably not possible). I had better start saving

[@proastroz5759]

You can't move the RA but of course you can unlock the DEC manually.

[@horvathrenata968]

I have ne ér heard about this telescope brand, but I like it

[@proastroz5759]

The RedCat71 is an amazing scope indeed!

[@jp7photography415]

Thank you.

[@vladimirmachek2524]

Nice review, thank you very much.... I would like ask you. Do you know how is periodic error of this mount ? I cannot find this information on Ioptron website. I just use Ioptron CEM60EC with periodic error 0,3 arcs. and I am very happy with that. It is very accurate. Just I am looking for some more light and portable and HEM 27EC is in my focus. My thank in advance.

[@proastroz5759]

Thank you for your comment! That is a good question. iOptron has provided some answers regarding PE in their FAQ here: www.ioptron.com/Articles.asp?ID=346 The EC is definitely light and portable and accuracy should be excellent. :)

[@vladimirmachek2524]

@@proastroz5759 Thank you, I have received information from Ioptron. For Hem 27 ec they use the same encoder like for Gem 28 ec, Cem 60 ec, etc. It means PE is the same 0,3 arcs. BUT gear have to be properly balanced. If you don’t use CW, PE is worse. This is the reason why they do not show this number in technical specification. Maybe good reason for testing. Clear skies

[@TedDobosz]

In my copy of the HEM27EC, the PE is very good. I cannot see it in 3 consecutive unguided 5 minute exposures with 11kgs scope and counterweight. I can blink the three images and no real change can be seen with the stars.

[@ppi57]

Is there a way to mount it to a flat top pier?

[@proastroz5759]

That should be no problems at all: as you can see , you need the centre pin for the mount base and the 2 screws for attachment. As long as you pier has this, or you drill a plate accordingly, it should be very straight forward.

[@fredmercury1314]

Does it being light actually make it less stable and more prone to vibration errors?

[@proastroz5759]

No, it's a very sturdy mount - very dense. The way it stands with no counterweight bars protruding helps that. The carbon fibre tripod is also fantastic. Honestly not a concern, anymore than other mounts.

[@alandyer910]

Looks very interesting. But you still need a Windows laptop computer at the scope to use the iPolar do you not? I assume an ASIAIR will not connect to an iPolar camera. Thank you!

[@proastroz5759]

Hi there! You do need a connection to a windows machine for the iPolar for now (July 2022), but that is only for the setup of the polar alignment (5-10 min procedure). Once polar aligned, the mount operates on its own. Of course if you use the ASIAIR you can simply bypass the iPolar altogether and use the onboard polar alignment feature from ASIAIR (with compatible ZWO camera).

[@alandyer910]

@@proastroz5759 Thank you! I hope they develop a mobile app for iOS and not just Android. That would then make electronic polar alignment with portable setups practical. We already have those computers with us.

[@rlynn36]

@@alandyer910 I recently got this email message from iOptron Tech Support: "iPolar software supports PC or Mac, not iPhone/iPad directly. We are releasing an adapter/APP for Raspberry Pi to work with iPolar which should enable wireless connection to iPhone/pad or Android."

[@proastroz5759]

@@alandyer910 I agree this would be a game changer. There is no reason for them not to do it! We know they are working on an app, not sure the platform of the extend of the functions. Fingers crossed!

[@kevinedw2002]

any update on performance?

[@Astrobomj]

What about guiding accuracy? And also inidylib support?

[@proastroz5759]

Still testing the guiding accuracy - it's non stop rain over here, so not much happening in this area unfortunately! Not sure about inidylib - a question worth asking iOptron directly.

[@kanakrt9210]

Hi, could you please tell me if the mount can handle an EDGE 8" SCT with AOG, DSO camera for deep sky astrophotography?

[@proastroz5759]

From the specs, the edge 8" is 6.5kg, with the extra bits, you should still have enough margin for good imaging. iOptron has a video with a C11 on it, but obviously not for imaging - impressive nevertheless!

[@kanakrt9210]

@@proastroz5759 would you prefer this HEM27 or the ZWO AM5 mount?

[@proastroz5759]

@@kanakrt9210 I have not had hands on with the AM5 - I don't think it's available yet? - but given this is ZWO's first foray into mounts, we 'll be waiting to hear how it performs before stocking it. It's not easy doing mounts!

[@zbnmth]

Thanks! How has the power down memory served you, if at all? How long does that function? Can you turn it off for, say, a week and it will still be aligned?

[@JohnICGomes]

Does this work with ASI Air Pro? Anyone tested it recently? There were some post of CloudyNights about people facing issues connecting.

[@proastroz5759]

Confirmed working with ASIAIR - connection through controller recommended. Have not tested connection through the mount direct, but will probably involve adding a USB hub like on the other mounts - this is due to ZWO's driver compatibility.

[@JohnICGomes]

@@proastroz5759 thanks again! Can you connect the AAP to the USB B socket on the dovetail saddle? Also the documentation says that the USB on the mount is a pass through to the saddle - what does it mean? Also for wifi do you need the hand controller?

[@davidbenefiel9289]

Not a lot of information for 6+ minutes of talking. How about alignment procedure? iPolar use? WIFI communication? Control using a smart phone? With SkySafariPro?

[@davids2000]

Can you use it in AltAz mode?

[@proastroz5759]

I don't think so - also you probably don't want to given the harmonic drive is on the RA only.

[@TARugg]

@@proastroz5759 Ioptron markets the HEM27 and HEM27EC as Harmonic Drive Hybrid EQ/AZ Mounts --- meaning it can operate in equatorial and alt-azimuth mode. If you are a dealer selling them, I would think you would know that.😄

[@proastroz5759]

@@TARugg I have seen nothing from iOptron about AZ for the HEM27 (unlike the SkyHunter you may be referring to?) and given you cannot actually get the latitude down to zero on the standard version (minimum is 15 degrees), I cannot see how it could possibly be used for AZ. That is unless you have the special low latitude bracket that works only from 0 to 22 degrees. So, on the standard version, no it cannot be used in AZ as far as I can tell.

[@proastroz5759]

@@TARugg In fact, here is an extract from iOptron's FAQ: " Why HEM27 is EQ only, will AZ be an option in the future? HEM27 is designed as a dedicated EQ mount since the high intrinsic PE of strain wave gear can only be suppressed by autoguiding or high precision encoder. Autoguiding and high precision encoder are not economically feasible for AZ mode. On the other hand, HEM27 comes with cable management system, and AZ mode might compromise the cables through the mount. A multi-function/mode mount sounds good, but there are some compromises to either mode that would prevent the mount to perform the best at either mode. "

[@TARugg]

@@proastroz5759 My apologies ProAstroz. You are correct and I am 100% wrong. Thank you for your clarification and I am still a bit sore for sticking my foot in my mouth!

[@ppi57]

Is there a way to mount it to a flat aluminum pier plate?

[@bobwilson8838]

Try taking the mounting plate off of the tripod then mount that plate on to your pier.