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ZWO 30 mm f/4 Mini Guide Scope

SKU : ZWO-30120

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  • This 30 mm (1.18-inch) aperture ZWO Guide Scope is compatible with all ASI cameras.
  • Optical Design: Doublet.
  • Aperture: 30 mm (1.18 inches).
  • Focal Ratio: f/4.
  • Focal Length: 120 mm.
  • Camera/Eyepiece Connection: M42x0.75.
  • Back Focus: Adjustable, 0 to 20 mm.

Product Details

  • Once attached to your ASI astro-imaging camera and a computerized mount controller, you will be able to guide your telescope to a desired area of the sky and lock it onto a specific star to hold your images stable.


    The optical lens is made of two simple lenses paired together to bring your images to focus and reduce chromatic aberrations.


    The aperture of this mini-guide scope is only 30 mm (1.18-inches), the focal length is 120 mm, making this a fast focal ratio of f/4. The tube can travel 20 mm, and the back focus is also adjustable from 0 to 20 mm. The overall tube length is 122.5 mm, with the final 3.5 mm being the length from where the camera connection threads begin. The inside diameter of the tube is 30.5 mm. The outside diameter is 44 mm. Your camera connection will be M42*0.75.

    Total weight including the guider ring and dovetail: 250 g (0.55 pounds).

  • specifications

    Aperture30 mm (1.18")
    Back Focus0 to 20mm
    Camera/Eyepiece ConnectionM42x0.75
    Dawes Limit3.87 arcseconds
    Focal Length120 mm
    Focal Ratiof/4
    Free ShippingYes
    Hightest Magnification60x
    Light Gathering Power18x
    Tube Length122.5mm
    Weight0.55 lb (250 g)
  • included items

    • 30 mm mini guide scope.
    • Dovetail with mounting ring (one-fourth-inch screw hole).

Product Reviews

Customer Reviews
4.8 Based on 90 Reviews
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Dave B.
United States United States

A Highly Valuable Piece of Equipment!

There's a newer version out with enhanced wifi, but for my purposes that hasn't been necessary. (I am working right next to the scope, though). Of all the equipment I've bought over the last several years, I think this was the most useful for the money spent. Seriously-- it makes alignment easier, it makes taking pictures easier, really it just makes the process easier! There is a bit of a learning curve, but compared to a lot of other apps this is easy. There are also lots of instructions online and on YouTube (check out Peter Zalinka's channel: That is a review of the new model, but he has others as well that show how to use this specific model. FWIW, I was able to use this with my Canon SL2 camera.

Eddie H.
United States United States

Exceeded expectations

Very happy with it

Jimmy W.
United States United States

It's the Apple of the telescope market.

This purchase made life simple. For those of us that don't wont to spend the first hour of the night making sure everything works and getting multiple different apps to all play well together this is it! Only down side is your locked into ZWO, but since I was already this was a no brainer for me. With a wi-fi extender I am able to set up my scope polar align then go sit in the living room spend time with the family and see everything going on with my scope outside form the I pad. Photos were taken this July in 2021 was out side with asi air pro. The best part was I got to sleep and let the ASI air pro control the scope! No more staying up all night to get several hours of exposure time.

OPT Telescopes ZWO ASIair Pro, 120 Mini, & Guide Scope Kit - ZWO-ASIAIRPRO-K2 ReviewOPT Telescopes ZWO ASIair Pro, 120 Mini, & Guide Scope Kit - ZWO-ASIAIRPRO-K2 Review
Elliott L.
United States United States

Highly Recommended

I have used the ASIair Pro since May 1st and really enjoy it. I can operate my EQ6-R Pro mount and Canon Ra using my iPad mini 2. The WiFi extender is necessary in order to image from inside my house.

OPT Telescopes ZWO ASIair Pro, 120 Mini, & Guide Scope Kit - ZWO-ASIAIRPRO-K2 ReviewOPT Telescopes ZWO ASIair Pro, 120 Mini, & Guide Scope Kit - ZWO-ASIAIRPRO-K2 Review
John B.
United States United States

Doesn’t work with a Mac unfortunately

Not good, I can’t use it.

A OPT Telescopes Customer
Tracy L.
United States United States

Oops. :)

From a noob to other noobs.. this system will use your dslr/mirrorless camera as main camera to align polaris. Be sure that your camera is supported before buying this handy device. At this time it does not support sony cameras. I can't use mine as a result of this right now. Though I'm keeping it for future growth into the hobby.