ZWO Off Axis Guider (OAG) v2
ZWO Off Axis Guider (OAG) v2ZWO Off Axis Guider (OAG) v2ZWO Off Axis Guider (OAG) v2

ZWO Off Axis Guider (OAG) v2

Now: £104.00 (Save:  £12.00) Was:  £116.00
  (8 Reviews)
✓ 2 year warranty


1x in stock shipped 1-2 working days

Black Friday & Holiday Sale 2023 - Huge savings on most ZWO products.

Sale Ends Midnight, 2nd January 2024 subject to availability.

About this product

Model:  zwo_oag
Part Number:  ZWO-OAG

ZWO off-axis guider (OAG) for astrophotography.


  • Lightweight and only 16.5mm thick!
  • Large prism - 8x8mm
  • Guide through your main imaging scope - no guide scope required!
  • Multiple adapters available including T2, M42 and M48 making it easy to fit to most cameras and telescopes
  • Fully compatible with all ZWO ASI cameras
  • Good stability - strong, stiff connection to the telescope

Adapters Included

Setup Guide

1. Calculate the correct distance for your imaging train. For example, you need to attach a 21mm extension to the ASI071 to reach 55mm back focus (17.5mm + 21mm + 16.5mm = 55mm).

2. Take off the guider prism part from the OAG and attach the OAG body to the telescope.

3. Insert the prism back into the OAG body.

4. Mount the guide camera.

5. Screw the T2 or M48 adapter on the imaging camera according to your cameras mounting type.

6. Mount the camera on to the OAG in the correct position and lock the 3 screws.

7. The final setup.

8. Check that the prism does not block the imaging area.

9. Use the guiding screw to adjust the guiding cameras focus. This is best done during daytime to make sure both the imaging and guiding cameras can focus at the same position.

What's in the box

  • OAG Body with M48 Telescope Adapter
  • 1.25" Eyepiece / Camera Holder
  • 5mm T2 Extension
  • M42 Camera Adapter
  • M48 Camera Adapter
  • M42 Telescope Adapter

Customer reviews

Average Rating (8 Reviews):  
Write a Review and share your opinions!

Rating (max 5):  
No more trails!
18 August 2023  | 

After excellent advice from the folks at FLO I upgraded my small guide scope to this OAG.
It was easy to set up with my 6" RC and is giving me round stars once I got PHD settings correct (the only fiddly bit).
The prism is small so a sensitive guide camera is needed. I'm using an Atik 314L and still only get a couple of guide stars depending on where it's pointing.
The included accessories are useful for getting it all connected with the telescope.
Thanks again FLO

Rating (max 5):  
OAG. 2
10 June 2023  | 

FLO were great as always, took a while for me to work out how to focus it (no instructions as is the way from ASI) and that the ASI 120MM should be used on this without the black spacer (I am a slow learner!) so that the chip is right on top of the aperture on the OAG and in the same orientation as the aperture which is obvious with hindsight but, when eventually I got it going, it was great and saves worrying about knocking the traditional guide scope off line as a bonus.

Rating (max 5):  
Fit not quite right
07 August 2022  | 

I found that when the lock screws are tightened, the OAG can nove in its machined slot, which is obviously a big no no. Perhaps mine is faulty....


There is an additional grub screw which may need to be tweaked as well but if that doesn't help, please get in touch and we can run through some other things to try.

Rating (max 5):  
Positive exxperience
18 March 2022  | 

Positive experience all around.Easy to set up during the day.Attain good guiding figures at night.There was less guide stars as is widely documented with OAGs but i had enough,at least with my chosen target(M51)in my field of view.Used with a QHY5L II MONO ( which i believe has the same sensor size as a asi120mm mini) and an eq5. sub arc second guiding all night @ 1280mm focal length.Thnks as always to flo for quick service.

Rating (max 5):  
Zwo oag
03 May 2021  | 

Fantastic service again from FLO. They are my go to supplier for all things telescope. The zwo oag was really easy to set up, just waiting for clear sky’s to give it a run.

Rating (max 5):  
Excellent quality from ZWO
09 April 2021  | 

The ZWO off-axis guider is a lightweight, well constructed instrument. It was easy to incorporate into my current set up, simply replacing the 16.5mm spacer between my Skywatcher ED80 telescope and filter wheel. It arrived promptly from FLO in their usual high standard of packaging.

However in use things proved more tricky. Whereas my ZWO Miniscope picks up lots of stars and I get guiding straightaway, there are of course fewer stars with the OAG. Guiding with the ASIair, and ASI120MM guide stars are getting lost. I am still experimenting, but suspect unless you have a really dark sky the prospective guide star quickly gets lost in the 'murk' of light pollution etc. So the OAG loses a star in this review!

Rating (max 5):  
Works well no more flex.
12 December 2020  | 

I was having trouble with flexure using a WO 72mmX 420 guide scope, with my 8" edge HD. This was easy to install and immediately solved the problem. The guide stars look like bananas but is not effecting the guiding performance. I am using the asi120mm guide camera and need to run it with a very high gain to get more guide stars. The guiding figures are the same for both OAG and guide scope but my stars are now round and zero field drift.

Rating (max 5):  
29 January 2020  | 

I married this OHG to an Atik EFW2 filter wheel. I contemplated drilling and tapping the OHG body to make use of the three screws in the EFW. These screws are the ones used by Atik for their OHG.
In the end I ordered an male/female thread adapter from Flow. To be able to fix the orientation of the guide camera by setting the height of these three screws. Focusing has been initially set in daylight using a distant tree so we are waiting for clear night for further focusing and testing.


Please fill in the form below to ask a question.

Please add the two numbers

Q1. How can I remove flex / wobble with the Prism stalk of my ZWO OAG?

Once you have adjusted the ZWO to be parfocal with the Imaging camera and have the Prism stalk adjusted to the position you require then you can tighten the two grub screws, one on the OAG body and one on the stalk, to remove any flex/wobble

The Allen keys required are supplied with the OAG

Related Products
ZWO 1.25'' Helical Focuser
£61.00  £68.00
ZWO 1.25'' LRGB Filter Set Optimised for ASI1600
£128.00  £142.00

Christmas at FLO:    Extended Returns    |    Last Delivery Dates    |    Astronomers Gift Guide    |    Kids Gift Guide    |    Beginners Telescope Guide    |    New Telescope Accessory Guide    |    Gift Vouchers