Rodney Post from Concord, CA United States
I don’t generally use barlows but my 30 year old TeleVue 2x has worked well enough EXCEPT on my longer eyepieces like the 16 Nag or the 24 Pan. I would get the predictable vignette of the outer field. I like a 2x power so I went for the E.S. 2x Extender and am happy with it. No more dimmed and fuzzy field stop and optically detect no degradation of the image. The two thumbscrews are redundant so I removed one and shortened the other making it more user friendly. All in a nice replacement for my old TeleVue.