ZWO Large Off Axis Guider

ZWO Large Off-Axis Guider

OAG-L is the latest iteration of M68 OAG with a larger prism size of 12*12 mm. 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. To take the most advantage of it, ZWO recommends you to match it with large format guiding cameras.

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

Operating Guide:
1. For guiding, OAG-L can only work with ASI Mini cameras like ASI174MM Mini, ASI290MM Mini and ASI120MM Mini.
2. Considering the large prism size, ZWO does not recommend you to use OAG-L with telescopes whose clear aperture is smaller than M48.
3. But it is recommended to use with APS-C cameras (ASI2600) or full-frame cameras (ASI6200/2400) respectively in combination with a 2" EFW or the 7x36 mm EFW as well. The large clear aperture supports full frame cameras without vignetting.
4. If you want to use the OAG-L without filter wheel, the adapter ZWO-D70-M54F must be used to connect the off-axis guider to the camera and achieve 55 mm backfocus. For cooled cameras with smaller sensors than APS-C, a ZWO-T2-Tilter-2 is also required.
5. 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.
6. 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.

The seventh and eighth image show how to the sensor tilt plate.

Please note:
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 distance 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 at daytime for the adjustment will be very difficult at night.