The Small QHYCCD off-axis guider is designed for QHY cameras with sensors smaller than APS-C format. Precision Connection, No Deflection The main purpose of the off-axis guider (OAG) is to use the same optical path as the main camera when guiding during astrophotography. Using an OAG avoids the problem of differential flexure that can occur when using a separate guide scope. With an OAG, part of the image is picked-off from the edge of the imaging circle which does not block the main CCD. Off-axis guiding provides more accurate guiding and sharper final images. The QHY off-axis guiders have an 8mm x 8mm multi-coated prism that picks off the beam for the guide camera. The position of the prism can be adjusted as needed and locked down. The main camera connects to the OAG with six 3mm screws that ensure connection accuracy and parallelism, providing a reliable and secure mechanical connection. QHY Off-Axis Guider for Small Cameras and Filter Wheels This small version of the QHY OAG only works with M42x0.75 adapters. It supports cameras with sensors smaller than APS-C such as the QHY224C, QHY290, QHY178, QHY550, QHY174, QHY183M/C, QHY163M/C, and QHY294M/C. It also works with the QHYCFW3S Small filter wheel. Precise Easy Focusing Each QHY OAG includes a non-rotating helical 1.25" focuser with a 6mm range to help focus an image on your guide camera. When using 1.25" guiding cameras, the position of these cameras can be further adjusted in the OAG itself to accommodate a wide range of back focus. Items included QHYOAG-S Small 2x M42 x 0.75 adapter plates (020082 & 020083) with optical thickness of 3mm each Attachment screws Specifications Model: QHYOAG-S Telescope connection M42 x 0.75 Maximum free aperture 38mm Connection screws 6 x M3, 54mm apart Sensor size compatibility Up to 4/3" Compatible products QHY183M/C; QHY163M/C & QHY294M/C with M42 male to male adapter; QHYCFW3-S Guide camera interface 1.25" Weight 127g Optical thickness 10mm without adapter, 16mm with both M42 adapters SKU QHY-OAG-S Downloads QHYOAG User Guide