Review: The AM3 Harmonic Drive Mount and TC40 Tripod from ZWO

Review: The AM3 Harmonic Drive Mount and TC40 Tripod from ZWO

by Al Milano (Urban Observer)

The AM3 Harmonic Drive Mount from ZWO is a Strain Wave drive telescope mount.

Photo credit ZWO / Stock photo.

The AM3 Harmonic Mount from ZWO - First Impressions

AM3 stands for Asi Mount 3 represents the model # (3 for the smaller model, 5 for the larger).

The AM3 Mount & TC40 Tripod arrived very quickly (in only a few days) to me; in (upstate) New York. I was happy to learn that ZWO has a US location, which isn't very far from me at all! Since I don't have a tripod which would be worthy of holding this amazing AM3 Mount: I requested the loan of ZWO's TC40 carbon fiber Tripod as well.

Each piece of equipment arrived double-boxed, and in perfect condition. 

Regarding The TC40 carbon fiber Tripod: When I first learned the retail price of this tripod; I was taken aback a bit. However, after having hands-on experience with it:

I realized it is a very well-designed, carbon fiber tripod, and is very sturdy! While being very lightweight at the same time. It's easy to set-up and fold-up for transport - Both for temporary transport: from one observing spot to another (when you move 5 to 10 meters); as well as more "permanent" relocation: Such as from one city or town to another! It's simply a pleasure to use; and it's obviously the perfect match (in fit & finish) when coupled with either an AM3 or AM5 Mount.

Furthermore, it seems that the price has dropped (to about ~ $349 US) at most telescope dealers.

The legs only extend one length, so the tripod doesn’t sit very high, when at maximum extension. I found it to be perfect for my needs, although some people might prefer a taller tripod.

When moving from one observing spot to another (just a few meters, for instance), I can lift and move it very easily. Try that with a typical mount! Try that with a large SkyWatcher mount...You may end up getting tripped-up! They can be pretty awkward and heavy to move - even if only a few meters! 

I remember reading many good things about The AM3 / AM5 Mounts, from fellow hobbyists on The Cloudy Nights Forum. They have always been highly regarded; and frequently recommended as excellent astrophotography mounts. Especially for users of medium to large refractors; as well as those seeking a grab and go mount for visual observing!

Can you recall anyone ever recommending one of the larger/bulky GoTo mounts for visual users? Me either. I think it says a lot about the value and utility of these mounts from ZWO. Even though there seem to be differing opinions, regarding it's suitability for visual-only users. 

The front of The AM3 Harmonic Drive Mount

I've come across forum posts, where some say it's not a good choice for visual use. Well, I've used it as a visual-only mount, with my Astro Tech AT80EDT refractor, and it served the purpose well.

So, as part of my evaluation and testing: I used The AM3 for visual observing only, for several nights. I found it to be be very comfortable and intuitive to use. I used all of the basic/default settings; and became very familiar, and comfortable with the scope's movements in relation to the joystick control (Alt/Az Mode recommended).

Additional benefits of The Strain Wave Drive technology:

·  You no longer need to even balance your telescope! This is great!

·  There aren't any clutches to tighten or loosen, lock or unlock, etc.

·  It is accurate! Strain Wave mounts experience very little periodic error (ZWO guarantees less than +/- 20 arcseconds (this is low enough to have no noticeable effect on your imaging).

·  It may function in both Equatorial and Alt/Azimuth mode. 

·  In addition, each AM3 and AM5 comes with a certificate, stating the (individual) mount's amount of periodic error - Awesome.

Unboxed and set-up - On The TC40 carbon fiber tripod by ZWO:

The AM3 comes provided with a sturdy, styrofoam-like box (similar to what The Seestar S50 comes with). Also included in the box:

·  The AM3 Mount

·  A 2-meter long, angled, gold-plated USB cable.

·  The unique PEC test report.

·  A Quick Start Guide (Instruction Manual).

·  The Hand Controller & Hand Controller cable (coiled, 2 meters long).

·  2 appropriately sized allen key wrenches (M6, and M4, for mount adjustments).

The AM3 can carry 17.5 lbs of equipment without a counterweight. If and when the need for heavier rigs comes up - Installing the optional counterweight bar & counterweight, allows The AM3 to hold 28.5 lbs of equipment!

All from a small, lightweight mount, which itself weighs only 17.5 lbs!

It features:

·  A strong load capacity of: 8kg- Without a counterweight - and 13kg with a counterweight installed.

·  It can function as an equatorial mount -Or- As an Alt-Azimuth mount!

·  It uses Strain Wave gear technology along with a synchronous belt system.

·  The AM3 (and AM5) utilize a compact and lightweight design.

·  The mount is provided with a hand controller, as well as WiFi, Bluetooth, and built-in Live Star Database.

·  It is ASCOM compatible (of course), and may be recognized as a (Meade) LX200 (by older software systems).

Following up on this last bullet point: I have tested The AM3 mount with a plethora of currently available software - And I have yet to find a software application which doesn't instantly recognize, and work with it!

At the most basic level, The AM3/AM5 mounts may be controlled by the ASI Mount App (both iOS & Android) freely provided by ZWO. I like the fact that firmware updates are automatically prompted.

At first, I found it quite amazing that such an advanced piece of equipment could be easily controlled via a smartphone.

Sharing some screenshots from the easy set-up process

beginning with the installation of standard ASCOM software/drivers:

Where you get the ASCOM software

Selecting/Installing (defaults) ASCOM software

When ASCOM Platform has been installed successfully, you'll see this:

The AM3 mount has a dual saddle; which means it can hold either a:

Vixen / V-Style -or- a Losmandy / D-style dovetail.

While testing the mount, I also checked out how it would work for visual astronomy. I first tried the mount in Equatorial mode. It took a little getting used to: remembering the directions in which the scope moves, in relation to the movement of the joystick. 

Afterwards, I switched it to Altitude/Azimuth mode, and it worked much better! Much easier to get comfortable with it's movements. This mount can serve many functions. The indicator on the mount lights-up green to indicate Alt/Az Mode (Red for Eq Mode).

Initializing Auto/Online Update for the AM3 Mount:

The AM3 Mount is automatically updating itself - Very convenient!

I was running N.I.N.A. at the time...

The AM3 Mount successfully updated it's firmware - Neat!

Yes - That's N.I.N.A.

The AM3 Harmonic Drive Mount may be ordered directly from The ZWO Site. 

If you live in The US, Astronomics carries the full line of ZWO Mounts and accessories. 

Additional features include:

·  LED status indicator (bi-color) to inform you of the Mount's current role (Eq. or AltAz.), as well as any error conditions. As does the lighted Power-on button.

·  USB port - A USB 2.0 port - For connecting to an ASIAIR, etc.

·  Auto Guide port / Guiding port (ST4 cable).

·  Hand controller port - This features a rocker-style joystick, which may be moved 8 directions.

·  12v DC power supply port.

Please note: The mount isn't provided with a power supply/plug. You can order the ZWO 12V 5A AC to DC Adapter, at time of purchase. ZWO manufactures Pier Extensions to be used by folks with much larger refractor telescopes. ZWO makes both 160mm (6.3") -and- 200mm (7.9") Extension Piers as available options for The AM5.

And, of course, the ZWO TC40 Tripod is perfectly matched to the AM3/AM5 Mounts.

At this point, I would urge you to visit ZWO's Page on The AM3 Mount, to see all of the technical features and specifications. There is even a Special WO RedCat Edition of the mount - A result of a joint project with Williams Optics - (another outstanding manufacturer of astronomy equipment). It's a Limited Edition, with only 35 units being made!

The AM3/AM5 mounts are very unique! They definitely take a bit of getting used to - The AM3 is unlike any telescope mount I've ever used. One of the main things you'll notice right away, is how easy it is to use. Once you begin using one of these mounts, it will be near impossible to want to use any other kind. Now, you'll have all this extra time available - from not having to adjust, and re-adjust the settings you would on a typical EQ mount.

All ready to go!

I've used The AM3 with all of the popular AP equipment control applications out there today. Including: N.I.N.A., APT, PHD2, etc.

As well as planetarium software, such as: Cartes du Ciel, Sky Safari Pro, and more! And it just always works! 

In addition to the TC40 carbon fiber tripod, which Astronomics happens to have a great price on; there are several additional accessories available - Which include:

ZWO Counterweight Bar, and ZWO Pier Extension for The AM5.

Note: I am not affiliated with Astronomics either, I just noticed that they offered ZWO products at good prices.

All ASCOM Components updated:

The AM3 (and AM5) Harmonic Drive Mounts from ZWO, are the kind of mount one would buy, when you simply want your equipment to work - and work well. If you are tired of mucking about with the "conventional" types of equatorial mounts: Loosening, and tightening clutches, spending time balancing everything (esp. if changing telescopes), having to carry/move an awkwardly shaped (and heavy) mount around - Then you should be looking into an AM3 mount.

And yes, you will pay a bit more for an AM3 Mount...But a Chinese adage comes to mind: "Cheap things are not good, good things are not cheap"

Once you use a harmonic drive mount, such as The AM3: It would be very difficult to go back to any kind of normal (non-strain wave) mount!

The AM3 Harmonic Drive Mount from ZWO

The AM3 was just a pleasure to use; it’s the sort of situation where the equipment is  almost “out of the way”. It’s not a burden (like many other conventional mounts can be). It allows you to focus on other aspects of your astrophotography.

·  Insure that the mount shows up in your list of Available Networks / Select it on your smartphone/or tablet (this also helps make faster connections in the future).

·  Bring your mount/rig outside - Mine is always ready-to-go, with The AT80EDT refractor on it. I’m sure this is common practice (with small-medium sized refractors).

·  Set-up rig: pointed North (polar alignment). Supply power/plug-in, power on.

·  At this point, you should be able to launch The ZWO Mount software, and select an object to slew to. 

While we’re on the subject of polar alignment… Polar alignment with The AM3 harmonic drive mount is different from what you’re used to…

So, I might go as far as to say that: In the beginning, you might miss the original way of polar aligning (I did!).

When you’ve done something the same way for many, many years – it’s not easy to learn/get used to a new way of doing it. 

With The AM3 Mount:

·  You make sure that your rig (mount & scope) is in the Home position - Not Park. *For those who aren’t aware, there’s a difference!

·  Then, you point your scope to your respective polar alignment position. For those of us in The Northern hemisphere, that is the NCP / near Polaris (“the North Star).

*Home Position, is the position in which you would point/align your telescope to the North celestial pole (for those of us living in the northern hemisphere). The South celestial “pole” / area for those in the southern hemisphere, to put it in simple terms. 

The “Park” position, was/is designed for use in an observatory. Those operating inside any type of observatory, would utilize the Park position, to keep the telescope out of the way, when opening/closing the dome.

I know, pretty neat, right? 

Everything is, of course, well-covered, and illustrated in the (freely downloadable) user manual. 

However, I will mention page 16 of the user manual; and draw your attention for a moment, to figure 3.4.1 entitled ‘How to adjust the latitude?’

Why this particular figure? Because the number 341 is some kind of lucky number for me, so there you go – maybe it’ll bring me some luck if I mention it in this review?

Some additional (selected) Specs:

·  Uses Strain wave gear + Synchronous belt technology; with a reduction ratio of 300:1

·  Typical periodic error of only +/- 15"

·  Latitude adjustment range: 0 to 90°

·  Maximum slew speed of 6° per second (pretty fast in use).

·  Mount can operate down to -40° Celsius 

There are two gears, to adjust the latitude on The AM3 Mount. This is done using the included M6 Allen key – by loosening two hex screws (counter-clockwise).

Gear 1: goes from 0° to 60°. 

Gear 2 goes from 30° to 90°. Again, it is all well covered, and illustrated in the (downloadable) user manual.

Switching The AM3 Mount from Equatorial mode to Alt–Azimuth mode, is done via the hand controller. You press and hold the ‘C’ (cancel) button, while turning on The AM3 Mount’s power button. When you release the ‘C’ / cancel button, the status indicator light turns to green, from red.

...Currently “migrated” to DSLR-based AP

Upon deployment, on subsequent nights, you’ll most likely just need to make a mild adjustment (to get accurate polar alignment).
Luckily, the overall accuracy of the mount helps matters.

Pros:

·  Lightweight, easy to move around/re-position.

·  Able to hold large telescopes, without much concern about balance/balancing, etc.

·  Robust, accurate, and fairly quiet.

·  Ability to function in equatorial, as well as Alt/Azimuth mode!

·  Boasts many features, including: WiFi, Bluetooth, and (wired) hand controller.

·  Operates seamlessly with just about all astrophotography software out there.

Cons:

·  Relatively expensive, compared to several (conventional) mounts out there.

·  The TC40 Tripod (which suits it best) may be considered a little expensive (although it can be found for as low as $349 at Astronomics).

·  Polar aligning will take some getting used to…

During my test period: I have used The AM3 Harmonic drive Mount in a number of different ways:

·  The conventional way: Using more than one model of refractor telescope for astrophotography (as seen in photos above).

·  Using both dedicated Astro camera (CMOS) and DSLRs.

·  With just a DSLR and telephoto lens.

·  As an Alt/Azimuth Mode mount: For both telescope, and binocular visual observing!

Just to give you an idea.

These are very low cost Barska brand binoculars (15x70)

I hope to get a chance to try a nice sized binocular telescope on this mount – personally, I think it would be a lot of fun!

I also enjoyed attaching my Canon DSLR and lens directly to this AM3 Mount, with great results (still post processing)…

The AM3 is obviously a versatile tracking mount, for more than just astrophotography - Although admittedly, I’m probably one of the few people who’ve actually used it for visual observing! Yes, it may seem a bit odd…but it is nice to know it can do it.

Aside from doing your polar alignment in a new, different way…The only obvious, and real “obstacle” I can see, is the slightly higher cost.

There are many astrophotographers, trying to accomplish some good astrophotography, while staying within a reasonable budget. For folks like us, the expense poses a bit of an obstacle. 

However, I could not see anyone spending the same amount of money on a non-strain wave mount.

As for a few specific examples, take the top end mounts from Sky-Watcher…

Equatorial, GoTo mounts, such as:

The HEQ5

The EQ6-R Pro

The AZ-EQ6 Pro 

The bottom line is that The ZWO AM3 Harmonic drive equatorial mount can be found for as low as $1499 US dollars at Astronomics.

So - this would be my recommendation (which, for many, will seem like a “no-brainer”) - if the Go To mount which you are considering, costs as much as (or more than) The ZWO AM3, I would advise you to go for The AM3. 

However, let’s not forget the tripod. If you don’t have a suitable/sturdy enough tripod - you’re obviously going to need one. 

You may find yourself leaning towards getting the TC40 Tripod from ZWO – because, of course, it fits the AM3 mount like a glove. They were basically made for each other. So you must take into account the expense of ZWO TC40 tripod, when considering the total cost of your mount.

A huge thank you, to ZWO for the loan of the equipment for this review!

Until next time,

Clear skies!