The bright Newtonian telescopes are among the most popular instruments for astrophotographers. However, their optics - regardless of the manufacturer - have one "annoying" defect, namely coma failure.
Coma: the enemy of bright Newtonian telescopes
The imaging of Newtonian telescopes gradually deteriorates from the centre of the field of view outwards, i.e. stars at the edge of the field of view will not be point-like even with the best focus. This phenomenon can be very disturbing in photographs taken with the brighter newtonian telescopes around f4-f5.
The Baader Mark III coma corrector is recommended for use with newtonian telescopes at f4.5-f5 brightness, it does not extend focus. It is free of annoying flare thanks to its outstanding coating. It has both T2 and M48 threads for camera attachment.
The Baader Mark III coma corrector can be mounted in a 2" focuser with a maximum free aperture of 44 mm to minimize vignetting. It is equipped with a filter thread at the bottom to accept 2" filters. Recommended up to APS-C sensor size.
