RE: ATM 4" scope plans...

["Mel Bartels" <mbartels@efn.org>]

>>>
My understanding is that the f/5 will be a considerably greater
challenge to parabolize than an f/6 or f/7. Others will comment
authoritativly on that point I am sure.
<<<

In the 4" size, the degree of parabolization is so slight that just a
minute of long wide strokes is all that is required.  The biggest
problem with the 4" size is that the glass is rather small with
respect to your hands.  Also, a 4" f/5 is a rather specialized
instrument because of its inherent low magnifications.  I would
suggest a f/8 to f/10 for a more general purpose 4".

Mel Bartels