I'm thinking of getting a Barlow corrector for my 300 f4 newt so I can have a range of focal lengths & fields of view. Right now my FOV is too small to handle smaller deep sky objects such as galaxies.
Normally barlows are used for planetary imaging where smaller CCD chips are used and the correction is only important in the center of the field.
I can't find much info for larger chips, like the STL.
The best option seems to be the ASA 2 " Barlow Corrector 1.8x
http://www.astrosysteme.at/eng/correctors.html
Off axis correction, vignetting, CFZ and arc/sec per pixel all look really good.
Some examples from Gerald Rhemann (the ones at f6.8)
http://www.astrostudio.at/all.php
Are there any other options that I should consider that will give as good results on a large chip?
Baader/Televue?
James