RainbowAstro RST-300 Weightless Mount

Rainbow SKU: RST-300
RST-300-1_1200px_q8-400x400 (6795890032793)
RST-300_CYG54G_DK10_1_1200px_q8-400x400 (6795890032793)
RST-300_CYG54G-1_1200px_q8-400x400 (6795890032793)
RST-300-2_1200px_q8-400x400 (6795890032793)

RainbowAstro RST-300 Weightless Mount

Rainbow SKU: RST-300
Regular price $8,490.00
Shipping calculated at checkout.
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  • capacity 66 lbs. (110 lbs. max)

  • Counterweights Not Required

  • Strain Wave Gear (Harmonic Drive)

  • Built-in brake (RA Axis)

  • 5-years warranty


Although the capacity is 30kg (maximum 50kg), the weight of the mount is only 8.5kg. It weighs about 35% compared to our worm gear mount and is less than 20% if we include the counterweight.

Counterweights not required

Counterweights not required up to 30kg. You can prevent accidents by the observer or guest from hitting the counterweight. Since there is no need for a weight bar, it is good for wide use of a narrow observation room.

Freed from balancing

The performance of the worm gear mount is sensitive to the balance, but the RST-300 is not. When two telescopes are mounted side by side, it is difficult to balance left and right, but using the RST-300 does not have such difficulties. You don’t need to rebalance if you change accessories like a camera or guide scope.

Strain Wave Gear (Harmonic Drive)

Instead of worm gears, a new type of reducer called strain wave gear (harmonic drive) is used. Almost no backlash and no maintenance is required. As it is widely used in industrial robots, it is very durable.

Built-in brake

The RA axis has a built-in brake system. When the mount power is off, the brake is activated to prevent the “back drive” phenomenon. “Back drive” refers to the phenomenon that the shaft rotates in the direction of gravity when the power of the strain wave gear mount is turned off.

CNC Machining

CNC machined aluminum alloy AL6061 is used for aircraft. That’s why it’s small, light and stiff. The beauty of the machined surface increases the collection value.


WiFi is built in. You can control the mount via the SkySafari app on your smartphone. Ascom Driver can be connected via WiFi as well as USB. GOTO and AutoGuide are now wireless.

GPS Receiver

GPS receiver is built in. The position and time of the observer can be entered accurately and conveniently.

Home Sensor

There is a built-in home sensor to find the mechanical origin. This is useful for permanently using Star Alignment data. Build an ultra-small remote observatory with the RST-300 mount.

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