|
As Robert says re the 2.5X barlow/powermate.
I can only tell you what I know. I use the 2X barlow with one extension tube if the seeing is below 4/10 seeing & add another extension tube to that setup if the seeing is better.
One extension tube is 85mm & the other is 90mm....which means nothing: the distance between the barlow element(s) & the camera chip is the thing to take notice of I assume.
|