The main purpose of the Off Axis Guider (OAG) is to use the same optical path as the main camera. This avoids the problem of differential flexure that can occur when using a separate optical system for guiding. An OAG provides more accurate guiding and sharper images.

QHY OAG’s include a precision 1.25-inch helical focuser that accepts QHY5II and QHY5III series cameras. The focusing process is smooth and precise. After focusing, you can lock the focus mechanism with thumbscrews.

Three QHY OAG models are available. The major difference is the diameter. The three models are QHYOAG-S, QHYOAG-M, QHYOAG-L. QHY OAG’s are thin and feature a solid design. The OAG main body is just 10mm thick. Adding an M42 thread or M54 adapter ring adds only 3mm for a total thickness optical length of 13mm. There are six 3mm through holes in the OAG for direct connection to the QHYCFW series filter wheels and QHY A Series cameras.

The light patch hole of the QHYOAG prism is 7mm for the guider camera.

Focusing:

The QHYOAG includes a helical focuser with a thumb screw to lock the position. When focusing please loosen the thumb screw. After achieving correct focus make sure you lock the thumb screw. To avoide damage, please do not move the focus ring when the thumb screw is locked. When it is locked, you will still find the focus ring can be rotate a little. This is normal, however the focus will not change.