Astronomy Specialist



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The Medium QHYCCD off-axis guider is designed for QHY cameras with APS-C, APS-H, and 36x24mm sensors with direct connection to the camera

 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 Medium-size Cameras and Filter Wheels

This medium version of the QHY OAG works with M42x0.75 and M54x0.75 adapters. It supports cameras such as the as the QHY294M/C, QHY165C, QHY128C, QHY247C, QHY367C and QHY600. It also works with the QHYCFW3-S, QHYCFW3-M and QHYCFW3-L filter wheels.

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 the QHY5II and QHY5III, the position of these cameras can be further adjusted in the OAG itself to accommodate a wide range of back focus.


  • QHYOAG-M Medium
  • 2x M42 x 0.75 adapter plates (020080 & 020081) with optical thickness of 3mm each
  • 2x M54 x 0.75 adapter plates (020078 & 020079) with optical thickness of 3mm each
  • Attachment screws


Telescope connection
Maximum free aperture 50mm
Connection screws
6 x M3, 62mm apart
Sensor size compatibility APS-C, APS-H, 36x24mm
Compatible products
QHY247C, QHY168C, QHY268C, QHY128C, QHY367C, QHY410C, QHY600; QHY163C/M, QHY294C/M & QHY183C direct connection with screws; QHYCFW3-S, QHYCFW3-M, QHYCFW3-L
Guide camera interface
Optical thickness 10mm without adapter, 13mm with adapter


QHYOAG-M (Medium) schematic.


Connection diagram for OAG Medium.

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