QHY Small Off-Axis Guider
The QHY OAG comes in three versions to accommodate image sensors of various sizes. All QHY Off-Axis Guiders have the same main body, which includes the prism, but the telescope/camera interface is sized to accept thread adapters of different diameters. Regardless of the diameter of the interface, it has six (6) 3mm holes and, without adapters installed, a thickness of 10mm. Both the telescope side and camera side adapters have a thickness of 3mm. The final thickness of the OAG depends on whether you need to use just the telescope side thread adapter or both adapters. If you are using the QHYCFW2-S, the QHY90A, or the QHY695A, it will connect directly to the OAG-S, and you won’t need to use the camera side adapter.
The “Small” version of the QHY OAG has a diameter of 54mm, and will only work with M42x0.75 adapters. This means it supports camera models with sensors smaller than APS-C format, which includes the QHY21/22/23, the QHY9, the QHY8/10/12 and any other model that has a sensor size of less than APS-C.
The QHY OAG has an 8mm x 8mm multi-coated prism. Its position can be adjusted as desired and then locked into position with a thumbscrew. This OAG also comes with a locking multi-thread 1.25″ focuser with an approximate range of 6mm. If you use the QHY5L-II as your guide camera, its position is adjustable when inserted into the QHY OAG-S. These two adjustments will give you a wide range of back focus.
Please Note: Choose the Medium version of the OAG if you want to use a camera with an APS-C, APS-H or 36×24 sensor, such as the QHY(IC)16200A, or you have the QHYCFW2-M filter wheel.
Choose the Large version if you have the QHYCFW2-L filter wheel or a QHY(IC)16803 camera. You can read more about the QHY-OAG-M here, and the QHY-OAG-L here.