Re: [APML]: Re: [APML] Help

[Brad Wallis <wallis@pepe.jpl.nasa.gov>]

...............
I'm having a problem with deep sky photos using my 12" LX F10. I tried to 
use the 6.3 focal reducer to reduce exposure times and make guiding 
easier.The results were terrible.I had severe vignetting(central glow) in 
the center of the print with a darker outer region.I live in area of 
..............

Most of the popular SCTs will not fill a 35mm frame without lots of 
vi8gnetting even at f/10 and the coma is 'fun' also ... so when you
drop in a field reducer you shrink down the linear size of the
fully illuminated field even more .... these field reducers are to
increase system 'speed' .. not to yield a larger field or a better
field ( although some image quality correction supposedly is 'built
in' to the focal reducers .... ) ... they work OK using CCD fields
of view ...

Brad Wallis