This coma corrector is the perfect photographic accessory for all NEWTON reflectors with focal ratio between f/5 and f/6 and flatten the field with the cameras also with large sensors (up to APS-C size 24x16mm). It fits in the 50.8mm focuser like a normal diagonal and it has, on the camera side, a M48 thread (male 48x0,75) for connection to the CCD cameras or DSLRs (with special M48 ring).
This coma corrector, to work best, requires you to place the camera sensor at 55mm from the back of the flattener thread.
For DSLR cameras, this distance is normally achieved by positioning (between the flattener and the camera body) a normal M48 ring. The CCD cameras instead have the sensor placed forward so if you want to connect them directly to this flattener will require an extension. In addition, most of the CCD cameras has a front thread T2 (42x0,75) then, to connect to this flattener, you will also need our "Adapter M48 female - T2 male" (which adds 8mm thickness). For example, since the CCD ATIK 428EX or 460EX have a back focus (distance between the sensor and T2 front thread) of 13mm, if we have to achieve 55mm:
55mm - 13mm (CCD camera) - 8mm (M48-T2 adapter) = 34mm
So you'll need a 34mm extension to bring the sensor to the proper working distance from the coma corrector.
- does not decrease the focal length of the instrument
- 50.8mm external diameter