Re: [APML]: Teleconverter or Barlow?

[Michael Stecker <mstecker@earthlink.net>]

Jim:
     I have not used my Genesis with a Barlow, but have used an
Astrophysics Barlow with the AP 130 mm f/6 telescope.  I took two photos
of 47-Tucanae globular cluster -- one with a Barlow and one without. 
The photos were taken at Las Campanas Observatory which has excellent
seeing. When I enlarged the non-barlow photo to the same size as the
Barlow photo it was obvious that the non-barlow photo was slightly
sharper.  I have used 2X teleconverter with a 180 mm and 300 mm lens and
have found that the results were not what I would have liked.  Adding a
Barlow will not improve the resolution of your telescope.  As always the
best thing to do is to make tests with YOUR system to determine which
method is best.  My limited experience showed me that it is better to
use prime focus than a Barlow or 2X teleconverter and to enlarge the
image in the computer or dark room.

                         Michael Stecker