The Telescope Authority
Since 1947

View Shopping Cart

Your Cart is Empty

ZWO 30 mm f/4 Mini Guide Scope

SKU : ZWO-30120

- Read
  • More on the way in 14-28 days

Add to Wishlist

Got questions? Click for live chat

  • 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
    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
4.7 Based on 15 Reviews
5 ★
4 ★
3 ★
2 ★
1 ★
Write a Review Ask a Question

Thank you for submitting a review!

Your input is very much appreciated. Share it with your friends so they can enjoy it too!

Filter Reviews:
  • scope
  • work
  • piece
  • equipment
  • manner
  • adjustments
  • system
  • exposures
  • weight
  • lens
Manuel C.
United States United States

Great service

Great service. Own three of these mini guide scopes. Work very well

United States United States

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

Wallace R.
United States United States

ZWO 30 mm f/4 Mini Guide Scope

Lightweight and easy to mount. Mounted on L-bracket with arca clamp to camera body. Used with ZWO AS120mm mini. Took some time to get the focal length right. Extended the front focus out nearly to the end and added the extension tube for the camera. Once I had that setup, I was able to focus just fine. Using with PHD2 and tracking went very smooth. Next test if the weather will cooperate is to use SharpCap to perform polar alignment.

United States United States

Zwo mini guide scope

Easy and lightweight. Great optics give pinpoint stars.

Jason R.
United States United States

Up and running

I'm just getting started in astrophotography and have paired this with a ZWO ASI120MM-S camera. It's mounted this on the side of a 5D Mark IV using an L-bracket and the whole system is running off a ZWO ASIAir Pro connected over wi-fi to my iPad. Very happy with how it's all working and this guide scope has made long exposures much easier.

Dave M.
United States United States

Effective and easy

Purchased this scope to use as a guidescope when imaging with my camera with a lens rather than a telescope. Paired this scope with an ASI120mm-s CMOS camera and attached it to a universal L bracket. the camera and guidescope work well together using PHD II guiding software. Once the initial focus is set the scope needs no further adjustments. The scope/camera combo is light and portable adding very little weight to my main camera and lens set up. This makes the whole rig easy to balance and the tracking is very accurate.