The Baader MPCC coma corrector (Mark III) is a popular choice for eliminating coma failure in newton telescopes. The phenomenon can be very distracting in photographs taken with brighter newton telescopes. The Baader MPCC coma corrector is recommended for f4.5-f5 brightness newton telescopes, it does not provide focus. It is free of annoying flare thanks to Baader's proprietary "Phantom Coating". It has both T2 and M48 threads for camera mounts.
The device can be mounted in a 2" rack, with a maximum clear aperture of 44 mm to minimize vignetting. It has a filter thread at the bottom to accept 2" filters. Recommended up to APS-C sensor size.
In addition to photographic use, it has adapters to allow use with 1.25" eyepieces.