Barlow/Powermate Question

From my understanding, a two inch 2X Powermate is the combination of a Big Barlow and a Panoptic Interface. Anyone know the reason why you cannot buy a two inch 4X Barlow instead of the 4X Powermate?
Thanks,
Barry

Barry Clarke wrote:

"From my understanding, a two inch 2X Powermate is the combination of a Big Barlow and a Panoptic Interface."

Your understanding is not correct. To understand the difference between a barlow and a Powermate, read the product information on Powermate available on the Tele Vue web site. There are some important distinctions.

Secondly, with regards to a barlow, the power achieved is determined by the spacing between the barlow lens and the eyepiece field stop. The longer this is the greater the magnification. The barlow is used designed to yield 2X when an eyepiece is inserted directly into the barlow. However, if you place a spacer between the barlow and the eyepiece, you will get greater magnification.

Darren