barlows basically double u'r ep collection. U get 2x from any eyepiece.. so the 20mm turns into a 10mm etc etc, although you do get a little loss in 'quality' when barlowing. So bascially with my 9, 15 and 25mm ep's i've got a 4.5, 7.5 and 12.5mm as well if i barlow them. I got the gso short barlow.. cause.. it's cheap.. and.. it's cheap. As a n00b spending big bucks on ep's at at the mo not really on the agenda. But if u did want to spend abit more the orion shorty plus is the way to go for around $150.. then after that if u wanna spend more look at the televue powermate.. big bucks but from what i've read are freakin awesome.
superviews give u a wider apparent fov, so you it's great for open clusters etc so u can fit more in, i think.. never looked through one.. so don't know for sure.. but this is just going by what i understand. But they basically make observing heaps more pleasant.
el
