The AP BARADV is supposed to offer the best of all worlds: lightweight, optically excellent, and versatile in which magnifications you can get, from 1.8-2.5x. Numerous reports from trusted members suggest it indeed a nice piece of kit.
However, I'm a little unsure about it, primarily because I find the available product copy on the internet to be rather lacking in detail. Here's what we have:
- Magnification factor 1.8x: @ 70mm back focus distance
- Magnification factor 2.0x: @ 79mm back focus distance
- Magnification factor 2.5x: @ 134mm back focus distance
Does the BARADV ship with three different-sized extension tubes, or is this BYOT (bring your own tube)? Or, are we meant to use a series of extension rings between the tube and the Barlow cell a la Baader Hyperion? In other words: What actually comes in the box? Is it just the Barlow element itself? If it does ship with a single extension tube, how long is it? And, how much does it all weigh? Got any pictures?
On the other hand, we have the GSO 2" Barlow which also gets pretty much universally good reviews. And just like the BARADV, the Barlow element unscrews and can be attached directly to an eyepiece. I also know you can vary the magnification by using different length extension tubes.
The BARADV is $250 while the GSO is $60, yet the seem to offer almost identical benefits. What am I missing here? How do the two compare, and how do they contrast?
Edited by thecelloronin, 17 June 2021 - 12:02 AM.