The ZWO M68 off axis guider is specifically designed for the ASI 6200 cameras and the 2" filter wheel.
This off-axis guider offers the best solution for guiding as it eliminates the problem of the differential flexure. This effect can arise when a guiding scope is used: while a camera is capturing an image with the main telescope, the guiding scope can flex to a different amount causing a guiding error. In other words, the guiding telescope does not compensate the mechanical movement of the main telescope during the exposure and as a result, the image can be blurred. An off-axis guider is installed on the main telescope before the camera so this problem does not occur as the guiding and imaging telescope are actually the same instrument.
The off-axis guide uses a prism that deviates part of the light from the main telescope and redirects it to the guiding camera. However, it will not block any light to the sensor or create any shadow if oriented on the right way.
The large 8mm x 8mm prism allows to get a large field of view for the guiding camera. That means a wider field of view and therefore higher chances to have a suitable star for guiding.
The off-axis guider reduces the overall weight of the telescope as the guiding telescope it not necessary.
This lightweight OAG has an optical thickness of 17.5mm. It is only compatible with ASI mini cameras.
This off axis guider is specifically designed for the ASI 6200 cameras. The combination ASI6200MM Pro camera (12.5mm）+ 2”EFW（20mm）+ M68 OAG（17.5mm）+ sensor tilt adapter（5mm) result in a total backfocus of 55mm.
1. Remove the 5mm tilt adapter using a screwdriver
2. Remove the cover of the EFW 2"
3. Disassemble the filter wheel carousel (Note: Please do not disassemble or move the central screw of this carousel, otherwise the EFW will be damaged):
4) Align the four screw holes of EFW with these in the four corners of the camera chip as shown below:
5. Tighten the screws at the interface between the EFW and the main camera:
7) FConnect the M68 OAG to the back cover of EFW(Note: You may need to reposition the prism to make sure it would not block the sensor):
8) Connect the 5mm sensor tilt adapter to this M68 OAG:
9) Reconnect the the back cover of EFW: