What is the main purpose of the QHYCCD Adapter Kit - Combo D2?
The primary purpose of the QHYCCD Adapter Kit - Combo D2 is to connect a Canon EF lens to a QHYCCD color cooled camera such as the QHY600C-PH or QHY268C (version before 2023), at the 44.1mm back focus Canon lenses require. It provides the specific spacing required to achieve correct back focus and ensures a rigid, secure mechanical connection to prevent image-degrading tilt or flexure.
Why is precise back focus so critical for my QHYCCD camera?
Canon EF lenses are designed to work at a very specific distance from the camera sensor (44.1mm). If this distance is even slightly off, you will see distorted stars, especially at the corners of your images. An adapter kit like the Combo D2 provides the exact combination of spacers and adapters needed to hit this distance perfectly, ensuring sharp stars across the entire frame.
How does the QHYCCD Adapter Kit - Combo D2 help prevent image tilt?
Image tilt occurs when the camera sensor is not perfectly perpendicular to the telescope's light path. This can be caused by sag in the focuser or loose connections. By using screw-fixed QHYCCD adapters and spacers, the QHYCCD Adapter Kit - Combo D2 ensures the camera is held rigidly and squarely, minimizing the risk of tilt and ensuring consistent focus across your entire field of view.
What kind of accessories can I connect with a QHYCCD adapter kit?
Combo D2 connects a Canon EF lens only. For other accessories QHYCCD offers separate kits, such as Combo D1 for a corrector that needs 55mm back focus and M48 threads.
Is Combo D2 the right kit for imaging the Pleiades (M45) with a fast f/4 Newtonian?
No. A fast Newtonian needs a coma corrector, and Combo D2 only sets the 44.1mm spacing for a Canon EF lens. For a corrector that needs 55mm back focus with M48 threads, Combo D1 is the kit for the same color cameras.
Can I use the QHYCCD Adapter Kit - Combo D2 with an SCT and reducer for the Orion Nebula (M42)?
No. Combo D2 sets the 44.1mm spacing for a Canon EF lens; QHYCCD does not list it for telescope reducers. An SCT reducer needs the spacing and thread its maker specifies, so check those before choosing QHYCCD adapters.