Quote:
Originally Posted by Shiraz
a Powermate is a Barlow with 2 extra lenses that make it telecentric. there is no real difference in this application, except that a Barlow can give you varying magnification whereas a Powermate is specifically designed so that it doesn't.
With a 618, the rule of thumb suggests that you need about 4x for your scope - just like http://www.astrobin.com/users/FranckIM06/
suggest a 3x Barlow with a short extension - that will allow you to vary the magnification to suit the seeing. |
Thanks mate. What do you mean by extension? Link? Picture of one?
Does the 618 fit into
this?
Baz.