Large parabolic mirrors are perfectly apt for Deep Sky imaging since they deliver a very large field and enable very short exposure times. However this comes at the price of off axis coma and some residual astigmatism. Coma will distort off axis stars into "comets" which effectively reduces the usable field considerably. Many companys offer various lens systems as solution to counteract coma, most at the downside of increasing the original focal length and reducing the field of view. An f4 optics may become an f4.5. The MPCC III is designed to be the most variable coma corrector in the market today without changing the telescope's focal length. It mounts into every 2" focuser and fits CCD-filter wheels and off axis guiders of various manufacturers.
no change in focal length or field size, an f4 Newtonian remains f4.
newly calculated lens system - designed for an unvignetted field down to f3.5
maximum sharpness across the field - without center soft spot (as reported of other)
accepts T-2(M42x0.75) and/or 2"(M48x0.75) threaded photographic- or visual-adapters
2" stopping collar removable for increase in backfocus
For photographic and visual use
easy to use
exceptional price/performance ratio
Phantom Group™ multicoated for maximum transmission and freedom from reflections from UV to NIR
backfocus from T2 thread: 55mm
backfocus from M48 thread: 57,5mm