Revelation Astro barlow?

[Mike73]

I've just picked up a used x2 Revelation barlow solely to use for very high magnifications on PN's with my Delos. These will be the only objects that I will use that high mags and as it was only a few quid I thought it was worth a punt.

Has anyone used one and know how well they perform?

Cheers

[JamesF]

I have the 1.25" 2x which is pretty run of the mill, and the 1.25" 2.5x which is right up there with the Celestron Ultima, I'd say.  I know they do a 2" 2x ED barlow as well.  No idea what that one is like.

James

[Mike73]

Thanks James

I have the 1.25" so will just have to try it and see I suppose, hopefully tonight if the weather stays like it is!

I'm hoping it will be ok though as it doesn't have to be sharp, just show contrast and magnify the PN.

[Reeny]

The 2.5x balow is multi element and the one I use.

It is excellent.

The 2x has less elements.

Note: the 2.5x has been tested by a forum member and found to be an actual 2.1x magnification.

I can vouch for that.

I was scratching my head with the calculations until I read the trhead about it being 2.1x actual.

[ScottS]

The 2.5x balow is multi element and the one I use.

It is excellent.

The 2x has less elements.

Note: the 2.5x has been tested by a forum member and found to be an actual 2.1x magnification.

I can vouch for that.

I was scratching my head with the calculations until I read the trhead about it being 2.1x actual.

Have you got a link to that thread? I'd like to read that. I have the 2.5x 3 element (I believe) Barlow and it works great.

[JamesF]

You have to be very specific about what you're actually measuring in terms of the multiplication factor of barlows, because what you get depends on how far from the lens you have your focal point.  This is why it is possible when imaging for example to add an extension behind the barlow to obtain a larger multiplication factor -- all you're doing is increasing the distance between the focal plane and the barlow lenses.

I'm not aware that there's any standard regarding where the measurement should be made, which is probably why barlows from different sources that are marked the same may give different results when compared with the same kit.

James