Re: (IAAC) FWD: What should I buy? (rich field scopes)
When I first discovered astronomy in the 60's, rich field telescopes
were quite popular, despite the horrible astigmatism at the edges of the
field of view. Today with coma and astigmatism correcting lenses for
newtonians, and fine faster refractors, rich field telescopes are more
capable than ever. Yet their popularity has greatly dwindled. Except
for my 6" f/4, I hardly remember an RFT at last year's TMSP or OSP.
Perhaps the big dob popularity and decreasing dark skies are to blame.
I would hazard an opinion that most amateurs have not looked through an
RFT, consequently the RFT experience is not well known or appreciated.
From nebula like the Cygnus Loop (easy) to the California Nebula
(harder) to Barnard's Loop (harder yet), from star clusters and
associations, and particularly the many dozens of dark nebula, to the
star clouds of the Milky Way, the RFT gives an unique and wonderful
portal to the sky.
An RFT can be a 4" f/4 with 24mm eyepiece and coma corrector to a 6"
refractor with oversized 2"+ diameter super low power eyepiece - the
idea is to go for the widest field possible.
By the way, RFTs can also be good high power high resolution scopes. My
6" f/4, which I spent a good deal of time on the mirror, can resolve the
larger Galilean moons into disks at 300x.
If you have not had an opportunity to do serious RFT observing through
all the seasons, you might consider it for your next project.
For more on RFTs, check out ATM I.
Clear skies, Mel Bartels // Programmer/Analyst, amateur astronomer
Springfield, Oregon, // USA homepage: http://www.efn.org/~mbartels
mailto:email@example.com // atm, atm-digest list-owner
Motorize A Dob: http://zebu.uoregon.edu/~mbartels/altaz/altaz.html