The 100mm are a little larger then needed I think. It puts more weight to lug around.
Before I jump in I want to look at a few and ask if I can take them outside and look at some long range shadows. I never was turned down doing that. I need to see it the outside lenses have any fog rings or shadows and the exit pupil has to be 5 to get the most light to the eyes. Celestron has a 80mm that looks interesting also, but the exit pupil is listed at 3.2mm but if this is at 25 power the high power will be awful dark. They don't say at what power that is.
And again even with multi coated High-Quality BaK4 Prisms and they say weather proof not water proof, that turns me off because I know it will be in rain at some point.
http://celestron.factoryoutletstore.com/...y_id=29968