The ULTIMATE astro lens for DSLRs

Why pay 99k for a lens, even if the price is in dollars?

My C5 makes a nice f/10 1250mm reflex lens for my DSLR. With a focal reducer it becomes a 787mm telelens and if I want something shorter I can always resort to the f/6 Scopos 66mm ED APO with a focal lenght of 400mm. At shorter focal lengths camera lenses are affordable.

John,

The Canon 1200mm f/5.6 is alot faster than a f/10 1250mm scope.
The canon lens is around one and an half f-stops faster, this means your shutter speeds can be one and an half times faster or more.
An f/10 lens would be too slow for a lot of wildlife and nature photography and some astrophotography.

Darragh

Agreed - but I tend to shoot things that stand still or can be tracked For fast stuff I prefer to get close in with a 50mm f/1.4 - on a Nikon DX that's equivalent to a 75mm lens used with the 35mm format - or use an 18-200mm f/3.5-5.6 DX VR zoom.