The Rainbow Astro RST-150H Telescope Mount Review

“Teeny.” “Tiny. Can lift it with one hand.” These are not words one hears applied to a goto smooth-tracking EQ mount. Normally it’s: “Big.” “Heavy.” “Gah, my back! Someone help me!”

Image 1

But the Rainbow RST-150H (Image 1) really is a one-handed telescope mount that’s super light. In fact, wonder of wonders, it weighs only 3.4kg (that’s 7.5 pounds for us backwards Americans) but carries 15kg (33lbs) WITHOUT weights or counterweight bar! Lemme say that again: WITHOUT weights or counterweight bar!

“How is this possible?!” I hear you cry. “Is it in defiance of the laws of the universe? Has Thanos snapped his fingers again? Is it…magic?” Nope, it’s actual engineering and a little thing we like to call a harmonic drive. Yup, the RST-150H does not use worm gears, stepper motors, friction discs, but harmonic drives, and these little suckers generate large forces for their size with almost no backlash, so, nothing to adjust, no muss, no fuss. And NO WEIGHTS!

And it’s cute. It’s so dinky.

But it’s a powerhouse that tracks with the best of them. What’s more, it has built-in GPS as well as a physical Home Sensor, so it can partially aid in a quick setup. It also has a built-in niche to just pop your Polemaster into, and voila: easy polar alignment, too.

And it guides smoooooooth. Seriously, no real spikes, so just a nudge of the guider every six seconds or so for me (though I was using a wide-angle rig) and it was fluid all night long (check out the Image 2 of the California Nebula NGC 1499). It will also transform into an alt/az mode when you need that sort of thing (as its usable latitude for EQ is 0 to 90 degrees). Oh, and it barely sips power, even when running at 9.1 degrees/second goto-ing.

Image 2

There are a few insignificant funky things to get used to, none of which are anything but simply “different” from other EQ mounts, so, no big thang. But, just so no one is surprised. Because this thing is ALL harmonic drive, the power and USB ports actually rotate with the RA axis. I didn’t get anywhere near cable wrap/tangle, but it’s something to be aware of. The azimuth locking knob is solid, but there’s a little waggle when locking. And, like all hand controllers, it has its own personal way of menu-ing. But, that’s kinda it.

Pricing is $6,500 in the States, but there’s more: a little sibling to the RST-150H is coming out soon, the RST-135, which will price out about $3,895! How good is that?

If you want the ultimate “grab-and-go” mount, carry-on-a-plane, even backpack, this puppy is it. Couple it with a light carbon fiber tripod, a small scope, and camera/guiding system, and there’s nowhere you can’t go with ease and fully loaded for bear (Ursa Major)!

Thanks to Tolga of Tolga Astro and Rainbow Astro for the use of the mount and in helping with any questions I had. Tolga’s one of those people who supports their products and astronomy helps at any hour of any day for anything. And remember: keep your eyes peeled for the RST-135!

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