Newtonian telescopes of faster f/ratio suffer the optical aberration called coma. Stars off axis are presented as stubby 'comet'-shaped objects instead of clean pinpoints. The farther off axis the worse the comatic blur, and the faster the telescope the worse the aberration overall. Enter the coma corrector.
There are two main forms of coma corrector presently available. The Tele Vue models slightly extend the focal length and f/ratio by a factor of 1.15, or 15 per cent. The Baader variant imparts no net change to focal length and f/ratio. The MPCC is optimized for f/4.5, but can be used to good effect between about f/3.5 and f/6.
The Baader Planetarium Multi-Purpose Coma Corrector Mark III incorporates new features to make it more versatile both visually and photographically.
Please note: This set replaces the former set #2458402 for visual and photographic application of the MPCC Mark III. The old set consisted of a multitude of rings – but was not adjustable in optical length such as this V-1 set.