Barlow lenses and apparent fov

[osbourne one-nil]

This is quite likely a very stupid question, but if it turns out it is, I'll pretend I was joking all along.

What effect does a barlow lens have on the apparent field of view of a given eyepiece?

When I got my TV85 a few weeks ago, I always assumed if I was going to treat myself to a new eyepiece, it would be a low-power, wide-angle one, such as the Panoptic 35mm. However, I got a chance to view Jupiter on Saturday night with my very old Meade 6.7mm super wide, and was blown away by it - far exceeded anything I'd ever seen through my big dobsonians (although it is far higher in the sky than it ever was with one of them). So now I'm wondering whether I should actually instigate a divorce and go for an Ethos 3.7 or 4.7. The thought of being able to see the whole of the Moon's disc at x150 is so tempting.

But....if I were to get something like an 8mm Ethos, and use it in conjunction with a barlow (assuming I could) would I still retain its 100º apparent fov whilst doubling its power?

Told you it was stupid!

[John]

If you get the right accessory, you can preserve even a 100 degree FoV. I use the Antares 2" 1.6x barlow with my 8mm and 6mm Ethos eyepieces and still get the full 100 degrees - that gives me 5mm and 3.75mm focal lengths. Another which I believe would work excellently would be Tele Vue's own 2" Powermate 2x - it's not a low cost purchase though !.

Don't abandon your plans for at least one wide field, low power eyepiece though - extended objects like M31, the Veil Nebula and galaxy clusters look superb though a nice apochromat

[osbourne one-nil]

Thanks John - seems better value for money than buying two Ethos eyepieces! I do already have a Baader Hyperion 31mm so I'm doing ok there probably, although it's by no means sharp edge to edge. Tonight might be properly clear and combined with no Moon and not being stuck in the office until midnight could see me having a few hours enjoying some of the Milky Way too.