The Next Generation of Harmonic Mounts is Here!

This video is sponsored by Squarespace. [music] New harmonic drive mounts keep coming out and with each new generation, I found they just keep getting better and better as the competition heats up. This video is going to explore the current state of the art through my reviews of three different harmonic drive mounts that I've been testing. The ZWO AM3N, the ML Astro Sall 33, and the Warp Astron [music] WD20P. Hello, my name is Nico Carver. I'm a full-time astrophotographer thanks to community support here on YouTube, but especially [music] through my Patreon, which is at patreon.com/nebulaphotos. This video is a long time in the making. I've had these three mounts for several months now and I've been using them that whole time to try to just get a really real feel for these mounts um so I could make the best review I possibly could. And these were all sent to me by their respective makers, so ZWO, ML Astro, and Warp Astron. And in all case, the makers of these mounts have no say in what I share in this video and no money has exchanged hands. I do want to thank these companies for sending out these review units and for allowing me to take my time with the review because with mounts, I think there's a real benefit to trying to get to understand them over a longer time period over several nights. So, let's jump into the comparison now starting with design and features. All three of these are called harmonic drive mounts or they're also sometimes called strain wave mounts because they use something called strain wave gearing. Um and that allows for the mount head to be much smaller than with a traditional worm gear type equatorial mount. Another big advantage of this type of gearing is that they can be used without counterweights up to a certain payload. So, this makes them ideal travel mounts for deep sky imaging. All three of these can be used in equatorial mode where the mount moves in right ascension and declination or in alt-azimuth where the mount moves in altitude and azimuth. Typically for astrophotography, we're going to operate them in equatorial mode, and for visual observing with an eyepiece, we'll operate in alt-azimuth. For equatorial mode to work correctly, the mount head has to be physically aligned with the uh central rotation of the earth. We call this polar alignment, and none of these mounts have a polar alignment scope built into them. Um there's no room, nor do they have robotic polar alignment currently. So, it's up to the astrophotographer to find a third-party electronic polar alignment method that works for them to polar align these. Now, that said, iOptron is working on releasing a robotic polar alignment kit for the CEM120, and this was something planned from the beginning with the design of this mount so that you can just unscrew four screws, replace the current alt-azimuth base with the robotic kit one once that's available. And the idea of motorized or robotic polar alignment is starting to take off more generally in the community. I'll be reviewing the Open Astro Explorer soon, which has that built in. I'm seeing other fully automated polar alignment wedges coming out soon, like the ZWO AM5, and the advantage of fully automated polar alignment is that we would no longer have to be physically at the mount anymore to complete polar alignment. I I would say that the current crop of electronic methods for polar alignment like ASIAIR or SharpCap are basically semi-automated. And what I mean by that is you still have to be at the actual mount turning the adjustment screws, but the software really does guide you through the process. And so, the whole thing becomes pretty straightforward and very accurate. I tested polar alignment on these mounts with several of these polar alignment software routines. They all work very similarly in that they take pictures of the night sky, so you need to be somewhat in focus, and then they move the mount in right ascension, and by plate solving the series of pictures, moving the mount around its axis, the software can calculate your polar alignment error, and then the software continues taking pictures in the last position, so that you can correct the polar alignment, giving you live feedback constantly on how to adjust the mount with the alt-azimuth screws. And the goal is to get these two numbers indicating your amount of polar alignment error and altitude and azimuth as close to zero as possible. If you get both these numbers to zero, that would mean the software believes you're perfectly polar aligned to the true celestial pole. SharpCap also has an option to correct for refraction, but I'm not going to get into that right now. I'll get into it in a different video. Generally, if we get it down to under 30 arc seconds of total error, that's good enough for excellent guiding performance on any mount. Now, the question is, of course, how easy is it to do that, to get it down to that very little polar alignment error with these three mounts? And I would say with enough practice, it's easy enough with any of them. The hardest to use adjustment screws of these three mounts are on the AM3N. When you're getting down to those final little adjustments, it's very easy to overshoot on the AM3N, and it can be more annoying on the altitude adjustment especially because if you overshoot and you already have the locks on the side fairly tightened, you can get into sort of this limbo where you have to turn the altitude adjustment screw quite a bit before you're actually moving the mount head in the opposite direction. This isn't too troublesome once you build up some practice using the AM3N, but I would rather have the polar alignment adjustment screws on the Cell 33 or the WD20P because they're objectively much more precise than the AM3N. And the precision is actually something pretty simple. If you look at the threading on the adjustment screws. You can see on the AM3N that the threading is fairly coarse, and that means a small turn of the screw will result in a big a fairly big jump in the error number. While on the Cell 33 and the WD20P, they use finer threads on the screw, and so a small turn will actually result in a small movement in the number. So, it's easier to dial in polar alignment with fine adjustments if you use finer threads on the screws. Of these three for the azimuth adjustment, which you can think of as left right, my favorite was definitely the WD20P. The combination of plenty of travel on the azimuth screws, the threading being super fine, and the knobs being this cross style rather than the barrel style of the Cell 33 and the AM3N gave me by far the most control. In altitude up down, my favorite was the Cell 33. The Cell 33 advertises zero shift with this adjustment, meaning that you can fully tighten the locking screws on the side here and still have full control over fine-tuning the altitude with this central screw. That feature does work, but it also works just fine on the WD20P. I can fully tighten the locks and still adjust with the main adjustment screw on the back just fine. Warp Astron does say if you plan to move more than about 5 degrees that you should loosen the locks, but generally, you know, after you set your altitude the first time, you're going to be always within a degree or two when you plop down the mount and start polar alignment. With the AM3N, it's a little bit trickier, but once you get close as long as you're just moving up not down, I think these side knobs can be fully tightened as well. Um so, that said, even though I think that zero shift is more marketing than a unique feature, I still give the Cell 33 the top spot for their altitude adjustment because you can see um here that the screw threads are very super fine. And Min told me that they started super fine screw threads with batch two of the mount and then upgraded all batch one users to this fine threading for free. And that super fine threading is noticeable for sure when you're when you're just dialing in the the altitude. You know, the SA23 definitely had the finest adjustments of these three in altitude, which can save a lot of time. With all of these, when adjusting in altitude, you want your finishing move to be in the direction that is giving you more resistance, which you'll feel with the screw. And I found for me that's almost always the up, which corresponds to clockwise on this screw. So, if I overshoot and the software is telling me to go down, I then purposefully overshoot again so that my final move in the altitude adjustment can be up or clockwise. And it's my opinion that this allows the polar alignment to be much more stable, no matter what mount you're using. Next, let's look at connectivity. All three of these mounts have both Wi-Fi and Bluetooth wireless connections. The wireless connections are very nice to have if you ever want to control the mounts from a phone or tablet. This way of operating the mounts is especially nice for visual observers because you can connect to the mounts to an app like Sky Safari and then just go to objects right from your phone. All three mounts should be able to connect to Sky Safari and use that as your planetarium for go-tos. Warp Astron does not appear to have a dedicated mobile app, while both iOptron and ZWO do have dedicated mobile apps for their mounts. In the case of ZWO, it is called Sky Atlas, and for iOptron, it is called iOptron Hub. I do think that it's nice that they provide these apps as they they work well for operating the mounts without any complexity. They can they can sometimes be a little bit of figuring things out to get a stable connection with Sky Safari, and these apps, uh Sky Atlas and M Astro Hub are both free, while Sky Safari Pro at least is $50. In terms of connecting to a Windows PC, M Astro Hub is also available as a Windows application, standalone, which is a bit slicker than their web portal, which is yet another way to connect to the mount over Wi-Fi for just basic configuration. Warp Astron has a dedicated Windows app also for configuration of the mount settings. It's called Mount PC Tool. It's on their website, and it comes with many advanced configuration options, so you definitely want to dig into it to take full advantage of the WD20P. For the AM3N, you have two options for mount control and settings on a PC. The ASA Studio app has a tool built in for mount control and configuration. The other option is the ASCOM driver, which has a I think all the same options. For the SA33 and the WD20P, you're going to be using the OnStep ASCOM driver for connecting to other software, but that driver doesn't have all of the specific mount configuration options that you can get with the dedicated apps for these two. But in any case, you will still want that ASCOM driver with any of these mounts um in order to connect them to other Windows applications if you're imaging with Windows, like PHD2 for guiding, and Nina or another sequencer to control the whole imaging session. Beyond PC control, another popular method for controlling the imaging session is the ASI Air by ZWO. All three of these mounts uh do work with the ASI Air. In terms of connection, the AM3 of course just connects automatically. It will pop up with the AM3 option. Um for the SA33, you want to choose the OnStep driver, just OnStep. And for the WD20P, you want to choose the OnStep Electronics driver, slightly different driver that works better with the Warp Astron mounts. In terms of physical uh ports, the SA33 connects with a B-style USB connection on the side of the mount. The AM3 connects with either a B-style connector on the front of the mount or a USB-C style connector on the back of the saddle. The WD20P connects with a USB-C connector on the front of the mount or on this port on the side of the saddle. The SA23 and AM3N are powered by 12-V 2.1-mm center pin style barrel connectors. On the WD20P, it's a 2.5-mm center pin and barrel connector. And also on the WD20P, it can take anywhere from 12-V to 25-V. The AC adapter that comes with the mount is 24-V rated for 10 amps. And this is one of the unique selling points of the WD20P. The P stands for power. There's also a normal WD20 that doesn't have the P. And on the saddle, you have these two USB-C power ports that can deliver up to 150 W of power when you supply it with 24-V. And where it gets really interesting is the Warp Astro sells this power hub for an additional $169 that powers off one of these saddle ports and then provides four 2.1-mm center pin barrel connector. Across these four power ports, you have 10 amps total. It's split into two 5-A channels. So, a single port can supply up to 5 amps. All of this power is supplied in a very sleek little box that comes with a Synta style finder shoe for attaching anywhere to your telescope. The AM3N also has some cable management built in. It has a 12-V power port on the back of the saddle. And then it also has a USB-C, which I mentioned earlier, which is just an alternative way to connect to the mount from your computer, whether it's an ASIAIR or Windows. The SA23 has no additional ports on the saddle, and that is on purpose to keep the cost down on this mount so that it can be more affordable. In terms of a physical hand controller, the AM3N comes with this basic joystick style controller. If you hold this cancel button for about 3 seconds, the mount will go to the home position. The Warp Astron comes with a small hand controller that connects over a USB-C The controller has several options actually, but a pretty limited set of physical buttons. So, if you plan to use this controller a lot, you will have to take some time to learn how it works. The quick start guide for the mount does explain the hand controller and all of its options pretty well. The Cell 33 has an optional hand controller for an additional $135. It looks similar to the one from Warp Astron because they're both on-step mounts. Okay, and then in terms of payload capacity how much you can put on these mounts. There are the published payload capacities without and with counterweights for these mounts that I'm showing you now. As far as I know, these capacities are all that ZWO has published on the subject. Both Warp Astron and ML Astro have published more nuanced takes on payload that take into account both weight, but also moment arm. Basically, how far away the center of gravity for your scope is from the mount head. And both weight and moment arm are going to have an impact on the amount of torque that goes onto the mount motors. And you don't want to exceed that maximum torque allowed by the design of these mounts. These mounts are in three different classes when it comes to weight and payload. The AM3N is the lightest and most portable. The WD20P is the heaviest just by a hair over the Cell 33, but it also allows for the heaviest payloads by far of these three mounts. So, the mount head weight to payload ratio is better with the WD20P. The Cell 33 is the most stripped down in terms of features and included items, but that also means that it's the most affordable option here, beating out even the AM3N by $250 right now. And with a significantly higher payload capacity that's more similar to the ZWO AM5N. All of these are sold as mount heads alone, and that is the price that I'm listing here. Of the three companies, ZWO is the only company that offers a tripod. The ZWO carbon fiber tripod is an additional $350, and you can order it packaged with the mount head or purchase it separately. Uh but it's called the TC-40. And the ZWO TC-40 tripod works with any of these mounts that I'm reviewing here. It's a really good option for travel since it's lightweight at 5 lb and packs down to fit in a suitcase. For heavier loads, like anything bigger than let's say a 6-in Newtonian or 120-mm refractor, I wouldn't recommend the TC-40. I would move up to one of the two options offered by High Point Scientific in their Apertura line. Uh the heavy-duty carbon fiber tripod is rated up to 110 lb, and it's adjustable from a height of about 18 to 30 in. For the ultimate in stability with bigger telescopes though, I would suggest the Apertura Inker Pier for strain wave mounts. It's the most expensive of the options I'm presenting. It's $800, but I've been testing it for the past few months, and as long as I set it up on concrete pavers to avoid potential sinking into the ground, I found that it's as stable as my permanent concrete piers in my observatory. It's that good. Even when using it, you know, with very large telescopes like the Askar 185 Apo. It's not something that you'd bring on a plane, of course. Uh it's too big and heavy, but you could definitely bring it in the car. In addition to tripods or portable piers, another optional item you may look into is a pier extension. Both ZWO and ML Astro make these, and the benefit to a pier extension is it's a stable way to move both the mount head and the telescope further up from the tripod legs, and that can help avoid collisions with a long telescope, especially when that long telescope is pointed near the zenith. I know some people are interested in how much sound these mounts make, both when slewing and when tracking. So, let's do some sound tests here. >> Okay, so we've done a a bunch of comparisons and now I just want to talk about what I see as the standout design feature of each of these mounts. Starting with the AM3N, the AM3N comes with a very lightweight but sturdy case. And for me, this is the ultimate mount for airline travel. I just went to Chile and inside this case, I felt comfortable putting the mount and the TC-40 tripod in my checked bag. And that ended up working out great. And at only 10 lb or 4.5 kg with the case and adding just 5 lb or 2.2 kg for the tripod, that gives me still plenty left in my checked bag for clothes and other stuff that I want to bring on the trip. So, that I think is the standout feature of the AM3N is that it's the most capable mount I can think of that is this lightweight and ready for airline travel. The standout feature of the Cell 33, other than the low price which I've already mentioned, is that it's designed to be easily repaired and serviced. And um Men has made all of his designs open source, so you can see exactly how this mount is put together, and he is working with the current developers of OnStep X to make OnStep mounts more and more capable, including the AM Astro mounts. I think it's also interesting that Min thought ahead to robotic polar alignment and planned to make it easy to remove the current alt-az base and replace it with the robotic one when it becomes available. And the standout feature of the WD20P, other than the power features, which are sort of obvious, that I've already covered, is that it uses servo motors rather than stepper motors. And so, why does that matter? I know that's sort of a technical decision, but the reason that matters is it's much easier to implement collision detection with servo motors. And you can configure the collision detection in the Warp Astron mount tool, including turning it off and on and fine-tuning how much force is needed to register as a potential collision. And that will stop tracking, of course, cuz you don't want it to just keep grinding the motors down. Before the WD20P, the only mount that I've had that will automatically stop when it senses a collision is the Astrophysics Mach 2 GTO, which also has servo motors and is a much more expensive mount. Okay, let's now turn to mount performance. The good news is that when you keep these mounts within specified limits, taking into account both weight and moment arm, they all perform beautifully. I found they all calibrated very well in terms of the guide calibration. In terms of guide exposure length, with good seeing, they all performed best for me with 0.5 second exposures. Interestingly, the SA33 and AM3N responded well to higher levels of aggression, while the WD20P did not. Uh for example, with the ASIAIR, if I just left it on the default guide settings of 70% aggressiveness on the RA and 100% aggressiveness on the DEC, those settings actually worked pretty well with the AM3N, slightly less well with the SA33 where it worked a little bit better if I lowered those aggressiveness settings, but not nearly as well with the WD20P. And in general, I found I had much better luck with the WD20P using PHD2 on a Windows PC where I could pick the guide algorithms and choose the Z filter algorithm. And you might be thinking this combination of settings means a lot of fast small corrections, and isn't there some worry with lots of small fast corrections that you'll be chasing the seeing. Yes, there is. But, according to the PHD2 manual, the best algorithm for that is the Z filter algorithm because it has the ability to use short guide exposures without chasing the seeing, the manual claims. And that seemed to play out in my testing. The ASIAIR doesn't have a choice of algorithms, and so I don't know if it's automatically switching based on exposure duration. My guess is not because with the WD20P, I could never get the guiding as good with the ASIAIR as I could get it with the full PHD2 on Windows. I could get acceptable guiding with the ASIAIR and the WD20P. I want to make that clear. Just not as good. And it basically what that means in as terms of a real world difference would be the stars is are probably going to be round in both cases, but the FWHMs, the the size of the stars will be slightly bigger with the ASIAIR given the same high resolution telescope. So, to wrap up, who are these mounts for? The AM3N, as I've mentioned, for me it's the ultimate travel mount, especially if you're flying and you're lugging all the weight. It's just great to have something lightweight with a light case that works and a light tripod. It also, unsurprisingly, works excellently with the ASIAIR uh cuz they're both made by the same manufacturer, and that's a great device also for travel astrophotography. I took this whole setup, the AM3N and the ASIAIR, to Chile recently with an Askar SQA55 and a Canon RF 85 mm lens on top, and this mount worked perfectly every night. No problems at all. The CEM33 is the best value I've ever seen in a mount. It performed beautifully with a Sky-Watcher 130 mm refractor on it with counterweights. So, you can put a pretty big refractor on it. At the current price of $1,249 US for all that iOptron is offering in terms of features, performance, and customer service, this is a no-brainer at this price. And then, last but not least, the WD20P is the most feature-packed harmonic mount I've ever used. With all these features and the high payload capacity, it's of course going to be the most expensive of these three at $3,500 US. But, I don't think that's an unreasonable price considering all of the tech that they're packing into this mount. Um the collision detection with the servo motors, all the modern USB-C connections, the optional power hub, the really large payload limit with a great payload to mount weight ratio, it's definitely my pick for using in a remote observatory. Um because, you know, of these three because the the collision detection I could see being very useful in a remote setting. But, it's also nice to have that setting anytime. I I found with my uh Mach 2. Especially with long refractors, um which this mount can definitely handle. So, when you get everything working well with any of these mounts and create the ultimate astrophoto, what do you do with it? Well, I'd suggest sharing it on your own website. And today's sponsor, Squarespace, makes that super easy. You can purchase your domain name and hosting all in one place. And Squarespace includes professional templates for your website that are intuitive and easy to customize due to Squarespace Blueprint, which is their design system. Everything you need is included from a spam-free contact form to selling tools built in. And if you do want to sell a service or product through your website, customers can pay however is convenient for them from credit card to PayPal to Afterpay. So, if you need a professional website, check out squarespace.com/nebulaphotos for your free trial. And if you like it, you can get 10% off your first purchase of hosting or a domain with code nebulaphotos at checkout. And since this video is over 20 minutes long, you're now seeing the names of everyone who supports this channel on patreon.com/nebulaphotos. [music] Patreon members get a bunch of exclusive [music] benefits like monthly bonus videos, one-on-one messaging support with me, tons of additional channels [music] on my Discord server including the monthly imaging challenge, um a one-on-one Zoom call with the whole Patreon community. That's the first Sunday of every month. And then that's [music] just a list of the benefits that everyone gets starting at $1 a month. There are additional benefits like early and ad-free videos starting at $7 a month. So, I think it would be [music] well worth checking out. Um you know, if you appreciate what I'm offering on this YouTube channel, check out my Patreon. Well, that's it for this one. This has been Nico Carver. Clear skies.