Mag of lens element on 2" ED Barlow

[Spec-Chum]

As you know the lens element on my Revelation 2” 2x Barlow can unscrew and attach directly onto the filter thread of an eyepiece apparently giving 1.5x.

But it seems, to my eyes anyway, to magnify more than 1.5x.

Some suggestions on the interwebs suggest it's more like 1.6x, but does anyone know the actual figure?

Or is it just my eyes?

[Tiki]

Could you not compare the field of view of your barlowed eyepiece and your eyepiece+lens combination?

eg. Stretch out a tape measure and have a look, or count the number of tiles on the ridge of a distant roof etc

[John]

I think it can vary depending on the optical layout of the eyepiece it's attached to and the spacing between the eyepiece lens elements and the barlow ones. The 1.5x is just an approximation as a guideline I reckon.

This is the same when you use some barlows in conventional mode with some complex eyepiece designs as well. I used to use a nice 1.6x barlow with my Ethos eyepieces but apparently the amplification delivered by the barlow with the Ethos optical design was not actually exactly 1.6x and varies from as much as 1.4x to 1.7x depending on the Ethos model being used and whether and spacers were used in the mix.

[Spec-Chum]

Makes sense. No biggie, I was just curious