mathieucarbou

Also to consider: - Stocks and sells: AM5 mounts are selling like pancakes and are nowhere in stock. HEM27 mounts are in stock and not selling as much - Support and Community: I am following both FB groups. ZWO clearly stands behind their products. When a problem appears (we saw that with the oil leak), they fix it and own the mistake. The support team and even their devs are answering on the group. They are involving also people in beta testing. I have an iOptron mount and always had quicker (and more relevant) answers from iOptron with emails. ZWO though has a far better community on FB and forums and it is really easy to reach the support team. iOptron clearly lacks a good community and marketing team. - Risk: both companies are new in terms of harmonic mounts... I don't see iOptron as a less risk factor than ZWO. Also, ZWO is a far superior software company than iOptron is. - Technology: ZWO went with 2 harmonic drives (RA and DEC) while iOptron went with 1 harmonic drive (RA) and belt drive (DEC), plus some EC versions with sensors, which is not dumb IMO. But considering the final products and specs, I find the HEM mounts really expensive compared to an AM5. - Testing & Review: far more people are testing and reviewing the AM5 mounts so even if they lack some features or have some drawbacks, the fact that there are less unknowns in those mounts can lead people to buy more of them. - Specs: I am not impressed with the HEM FAQ. it looks like I am reading a paper to defend the design of the HEM. And what I don't like is that some arguments are made without proof, we just need to be ok with the fact that iOptron "doesn't believe" in such things. I don't throw 2 grands on a mount because a company has some unsupported beliefs, when ZWO team at the opposite explains in technical terms why they did that and how it works. Plenty of info on the website, groups and forums. In the FAQ, the screenshot at the bottom is misleading. It shows an EC version of the mount but guided at 5 seconds. What's the point ? To see the real perfs of the mounts, we would like to see a HEM guided at a higher frequency (0.5s or 1s) which is typical for harmonic mounts. And also a graph of the EC version unguided to see how the real-time EC works with sensors. None of them are shown. Also, harmonic drives seem to come from nearly the same factori(es). Like iOptron said in their FAQ, they should have the same behaviour. Except that ZWO made a deal to test them and ensure those within ZWO specs will be in ZWO mounts... - Period and tracking error rate: The period is not the same: AM5 is 432s, HEM27 360s and HEM44 270s. Regardless of the drive type, the longer period the better. Even if a period with a longer period could lead to more absolute diff (errors) in arcs, what is important is not how big the error can be (amplitude) but how quick the error arrive (steep): so simply if the curve contains steep intervals or not. Dividing the length of the steepest interval by its duration gives the limit for the mount in arc-sec. So the longer the period, the more chance to get low inaccuracy rates. A curve that is having a higher frequency will have steeper ups and downs. So the HEM44 mounts I guess will definitely need to be guided at high frequencies. On ZWO group, we saw many users with good PE reports being able to do exposures of 10-15min unguided (with a 400mm FL or less of course). - Design: this is a very personal opinion, but I like the AM5 design more. They also have a very good ecosystem and quick release system with their tripod and pier. - Software: considering that these mounts now tend to be less "cable-operated" but more and more driven by technology, software and apps, ZWO has a strong developper team, while iOptron apps are really ugly and not on all systems and devices. I have more confidence for example in doing EAA with the Am5 mount and the ZWO AM5 app (which has an included planetarium). So to me, there are too many uncertainties and hidden facts in HEM mounts that, IMO, make them expensive and a risk far more than AM5 mounts. And I have an CEM40 🙂 So I don't dislike iOptron mounts. It's just that it seems to me they have rushed out the HEM mounts and didn't take the time to properly build a community, have proper tests, reviews, better specs and arguments and technical explanations of their design to make people attracted in them. That's the thinking process I had when I've made my decision.