ATM Re: Focuser Baffling

[Andrew.Martyn@dao.defence.gov.au]

I've had a look at a few sites that talk about baffling the focuser tube
and I am a bit confused. I can see how it can be of use with medium to high
power eyepieces(less than about 0.5 degrees fov), but surely in low power
eyepieces it will cause vignetting. For example with my low profile
focuser, I already get some vignetting caused by the focuser tube with my
low power eyepiece (1.1 degrees fov), although this is not too much of a
problem as there is already vignetting by the diagonal. I cannot see how
baffles can be used with low power eyepieces, which have a field lens
nearly as large as the focuser tube ID, without vignetting the edge of the
field further.