ZWO AM5 Mount' Review

ZWO AM5 Mount Review

by Joe Bergeron

Stowaway on AM5

Edge 8 on AM5 mount with ZWO ASIAir Pro and ASI294MC Pro camera.
Note the counterweight.

No more balloons!

I will preface my review with a few lines about why I wanted the AM5 mount. I have two other mounts capable of imaging. My estimable Losmandy G11 is a pretty reliable platform, but over the years it has somehow accreted enough mass to be difficult for me to move around. My lowly Celestron AVX is capable of handling my smaller, shorter scopes, but is somewhat inconsistent in guiding and generally a bit finicky.

Thus I wanted something lighter than either, but also more precise and consistent in guiding. I obsessively studied the harmonic or strain wave mounts when they first appeared, but the first ones, for example by Rainbow Astro, were super expensive.

Eventually ZWO introduced its AM5. As an owner of ZWO cameras and an ASIair Pro, I closely followed the experiences and results of early adopters. Soon enough my psychic powers told me this was the mount for me. After the usual agonized indecision about what was, for me, a major purchase, I ordered one, receiving it weeks later in January 2023.

Winter weather kept me from venturing out with it for weeks. The first crazy thing I did was to set it up inside my apartment, make the best polar alignment I could with a compass and inclinometer, and guide on stars visible through my west-facing windows with their far from flat glass. Despite these unfavorable circumstances, the thing guided at about 0.8 arc seconds of total error, very encouraging.

Finally in February I forced myself out on a cold night to try some actual imaging using the ASIair. After figuring out that I needed to increase the gain on my guide camera, the mount began to deliver guiding with a total error of 0.3”-0.5”, with rare excursions not exceeding 1”.

Since then I’ve used it many times, with similar levels of guiding accuracy. I’ve used it with three telescopes: a dinky AT 60ED with a focal length of 370mm, my trusty Astro-Physics Stowaway at 630mm, and even my Celestron C8 Edge HD at its full focal length of 2020mm. It handles them all with aplomb.

The only time its performance was compromised was with the C8 on a windy December night, reducing guiding performance to around 1”, with gusts taking it to 5-6”, ruining several subs. Even after discarding those, the images were not very sharp. I was using the ZWO carbon fiber tripod that night. In the future, I think I’ll use my steel AVX tripod with that telescope instead.

I use a 10 amp power supply, and have had no trouble running the mount, plus the ASIair, the main camera cooler, and two dew straps or rings from it at the same time.

The polar alignment adjustments can be fiddly, but once you start using them with the locks tightened slightly, they are manageable.

I've found that guide exposures of 1 second work well, with maximum pulse durations of half that, and aggression of around 50% on both axes.

Aesthetically, the red anodizing is beautiful, but I can’t stand that silly balloon graphic on the front cover, so I covered it with a sticker of my own design.

The degree of automation I achieve with the ASIair controlling this mount is remarkable. The plate solving alone seems almost miraculous. I feel comfortable going to sleep while the telescope quietly goes about its business. And it’s so quick and easy to set up, take down, and transport.

I hope this splendid little mount will remain reliable for whatever time I have left to pursue amateur astronomy.

The Christmas Tree cluster and nebula, shot with Stowaway

NGC 7331 shot with Celestron 8" Edge HD.