Brand: ZWO

ZWO Off-Axis Guider for ASI Mini Cameras (ZWO-OAG-L)

Brand: ZWO

ZWO Off-Axis Guider for ASI Mini Cameras (ZWO-OAG-L)

$197.00 USD

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$197.00 USD

Easy Payment Options with .

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Product Description

OAG-L-68 Has been discontinued. 

For guiding, OAG-L can only work with ASI Mini cameras like ASI174MM Mini, ASI290MM Mini and ASI120MM Mini.

OAG-L has a large prism size of 12*12mm, far bigger than M68 OAG. The bigger clear aperture brings wider field of view in guiding. It is easy to use, and suitable for users who are interested in long focal length photography.

OAG-L-68 shares the same prism size of 12*12mm as the OAG-L. It’s specially designed for ASI461 and ZWO 50mm square filter wheel.

To take the most advantage of it, we recommend you to match it with large format guiding cameras.


  • Lightweight and exquisite, 17.5mm thickness.
  • Prism size: 12*12mm.
  • The effective light-passing aperture is 11.7mm*8.3mm.
  • Can be used to connect the main camera and guide camera simultaneously. No guide telescope required.
  • Packaged with an M48 sensor tilt plate (5mm).

Operating Guide

  • For guiding, OAG-L can only work with ASI Mini cameras like ASI174MM Mini, ASI290MM Mini and ASI120MM Mini.04
  • Considering the large prism size, we don’t recommend you use OAG-L with telescopes whose clear aperture is smaller than M48.
  • Yet it is recommended to use with 2” EFW or 7x36mm EFW, and with APS-C cameras (ASI2600) or full-frame cameras (ASI6200/2400). The large clear aperture supports full-frame cameras without vignetting.
  • The major differences between OAG-L and M68 OAG are about the prism size and the threads. OAG-L removed the inner threads so you can directly use the screws to connect it to other equipment.
  • If the thread of your telescope side is M48, then you don’t need to remove the M48 sensor tilt plate coming with OAG-L. On the contrary, you need to remove it and use some other sensor tilt plate at the corresponding thread of your telescope.
  • While adding OAG-L into your optical train, please make sure the prism won’t block the camera sensor.
  • You can use the guiding screw to adjust the guiding camera’s focus length.
  • Please make sure the distances from the prism to the main camera and to the guide camera are the same. To ensure the result, it is better to do this during the daytime for the adjustment will be very difficult at night.






Customer Reviews

Based on 4 reviews
Solid Setup

New imaging train with the ZWO ASI2600mc Pro, ZWO M54 adapter(ZWO-D70-M54F) , ZWO Off-Axis guider OAG-L, and ZWO ASI120mm mini guide camera

Fits perfectly

Purchased this for rig #2 for wide field use. Rigid, solid, simple install. I swapped out the included tilt plate for the larger M68 version to take advantage of the wider telescope opening I had to keep the prism pick-off mirror well away from the optical path. Just be careful when adjusting for tilt, those small screws (not the adjustment set screws but the "locking screws") can strip the threads in the OAG metal fairly easily, don't need to torque them by any means, just tight enough until you feel some resistance and that'll mean it's secure. I wrapped a strip of tape around the thin gap after tilt adjustments as added protection from both light intrusion and for dust mitigation.

Nice but it’s not for me

I put the OAG-L on an EdgeHD with a .7 reducer and an M48 T-Adapter, the OAG-L 5MM tilt ring screws directly to the adapter. With my full frame sensor I had to place the prism into the heavy vignette of the image cicle, this makes it difficult to find stars for initial setup. I put my 30mm guide scope on an Antares hot shot with the 174mm CCD; and with the ASI Air and AM5 I achieved guiding of 1.2” or less. I prefer this approach because there are more stars available for guiding and it’s easy.

Nice Off-Axis guider

Good quality and fast shipping.

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