Astrodevice logo
Connecting Canon RA to RASA 8

Adapter for Canon RF-mount cameras and RASA 8

The device is designed to connect Canon cameras with RF mount to RASA 8 telescopes.  One of the most well known of these types of cameras, the one dedicated for astrophotography is Canon RA.

The adapter is screwed directly onto the telescope using a large M87 nut.

Thanks to the fact that the nut is integrated with the rest of the adapter, the camera is mounted perfectly centrally. However, you can still adjust the rotation angle as you wish.

Front Tilting Mechanism enables adjustment of the tilt angle of the sensor. It’s an system similar to the one mounted on dedicated astrophotography cooled large-sensor cameras, but its unique feature is the mounting on the side of the telescope connection 

The design is also equipped with internal an internal thread for 2″ filter. To use it you have to unscrew the glass window from the telescope, which is also recommended by the telescope’s manufacturer in their documentation when using any filters. As usual in similar situations, if you would like to shoot full-spectrum, it is probably worth considering a UV/IR cut filter.

CRF R8 adapter
Canon RF-mount to RASA 8 adapter

The device is made to keep the backfocus as close as possible to 28.73 mm, that is the distance from the front of the telescope to the camera sensor. The construction has no additional calibration screws and manufacturing tolerance is 0.1 mm. The whole thing – like all my adapters – should be made with 3D printing technique using PET-G reinforced with carbon fiber.

Going full-frame with RASA 8

The RASA 8 telescope was designed to guarantee ideal image quality up to APS-C format. Full-frame sensors are much larger than this. Therefore, when using full-frame cameras, you can expect vignetting of varying geometries, depending among other things on the design of the camera itself. For example in Canon Ra cameras dedicated to astrophotography the vignetting takes on quite a classical shape but from the top and bottom an even, linear, darker framing is visible. This is quite normal, but it is good to know what you should expect. These darker areas can be corrected to some extent with flat frames and the remaining imperfections can be removed in post-processing, possibly by cropping the image to a slightly smaller format. This edge processing will also help to deal with the optical imperfections that appear when working with large sensors and small backfocus.

In summary, full frame photography is entirely possible with the RASA 8. In case of Canon cameras with RF mount, all you need is an Astrodevice adapter.

Scroll to Top