03-16-2015, 01:06 PM
Best bet is probably a Maksutov-Cassegrain type telescope with appropriate adapters. These are the more common type at smaller aperture sizes, but they also tend to be relatively slow. For example I have one which is 1350mm f/13 and unusable hand-held. There are other configurations which can give relatively faster designs, but they only tend to be used at bigger aperture sizes which still wont be usefully handholdable.
<a class="bbc_url" href="http://snowporing.deviantart.com/">dA</a> Canon 7D2, 7D, 5D2, 600D, 450D, 300D IR modified, 1D, EF-S 10-18, 15-85, EF 35/2, 85/1.8, 135/2, 70-300L, 100-400L, MP-E65, Zeiss 2/50, Sigma 150 macro, 120-300/2.8, Samyang 8mm fisheye, Olympus E-P1, Panasonic 20/1.7, Sony HX9V, Fuji X100.