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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
4.6 Based on 81 Reviews
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Filter Reviews:
robert u.
United States
Great combination

I love how simple and portable this combo makes an astrophotography setup. ZWO is constantly updating the asiair's software with really nice updates. There are still a few quirks that I am sure will get corrected in short order. I had to use an external access point as the built-in wifi antenna just isn't sufficient for my use. That is primarily the reason this is not a full 5 stars in my review. I would recommend this combo for its value.

United States United States

Great little scope; so far no issues. Works well.

Dan M.
United States United States
Basically a waist of money

Well every word is towards how easy this makes astrophotography!..Not!!..Doesn’t give you any help in setting up your ZWO cameras so there’s that.You must already know all the settings before using this device so use sharpcap to set up your camera.Now update today and it will no longer connect to my mount!..It seems more like a toy and most of the mounts it uses are the high priced ones.It actually did a better job focusing my DSLR camera better than the ZWO camera ...So finally tonight after two weeks if clouds I’m ready to take some pictures.Then it updated the firmware and now it is a box with pretty lights that doesn’t work on my mount.I will be running my camera through the mount skywatcher app and focusing manually using dslr tonight Same setup before I purchased the ASIAR PRO. I don’t know who is writing the reviews but if your new to this hobby this will not help you learn the ZWO cameras and good luck connecting the mount!..

Michael L.
United States United States
ZWO ASIAIR PRO imaging success.

I had so much success imaging with my first ZWO ASIAIR Pro, I decided to order a second unit for another telescope. Now I can quickly change scopes without remounting the hardware. Capturing images is really enjoyable and it’s easy to experiment with new techniques as my skills evolve. Great purchase. Quick and reliable delivery from OPT.

OPT Telescopes ZWO ASIair Pro, 120 Mini, & Guide Scope Kit - ZWO-ASIAIRPRO-K2 Review
David A.
United States United States
Reduced the complexity of my set up

Migrated from a Raspberry Pi running Astroberry and laptop as terminal. No longer need 110 V. power to keep my laptop going all night. Using an iPad now and love it. Purchased a ZWO EAF to go with it and last time out was polar aligned, focused, plate solved to my target galaxy, and live stacking in 23 minutes (not guiding). If you can go all ZWO, I really recommend the ASIair.

OPT Telescopes ZWO ASIair Pro, 120 Mini, & Guide Scope Kit - ZWO-ASIAIRPRO-K2 Review
United States United States
Using with Star Adventurer for Guiding

The ZWO ASI120MM Mini the the 30mm f/4 Mini Guide Scope works awesome for help with guiding the Star Adventurer to keep the stars from trailing with a longer focal length lens. Shipping was quick and packaged very well. No regrets purchasing from OPT.

OPT Telescopes ZWO ASIair Pro, 120 Mini, & Guide Scope Kit - ZWO-ASIAIRPRO-K2 Review