Is this barlow good?

[Daveskywill (David)]

Hello:

I haven't bought this one yet, but wondered about it:

the Orion HighLight 2" 3x 5-Element Barlow Lens.

It says it's 2", but the clear aperture on it is only about 26mm (so around and inch)... plus with 5 elements it might not be good for fainter things I'm wondering.

And wondered if it would be good for Jupiter. I've only got one (good) 1.25" barlow, 2x. And maybe with Jupiter so bright I could have money and buy a better 1.25" (barlow) with a time or two higher power.

I appreciate all the advice.
Thanks

[darbyvet (Carl Darby)]

Hi David,
I use a Televue 2.5x powermate for imaging Jupiter.It is different than a barlow-you dont lose anywhere near as much brightness as you do with a regular barlow.They are expesnive, but far superior to a barlow in my experience and actually not that much more than a really good barlow.

[Daveskywill (David)]

Thank you. I've checked into the TeleVue PowerMate. And I think I'll buy

one.

David

[traveller (Bo)]

Its worthwhile remembering the inverse light transmission rule. For every doubling of power/focal length, you half the light transmission, and therefore dim-ness of the image. So while a 2.5X barlow gives you greater magnification, the image will be dimmer than a 2x barlow (assuming other things such as lens construction and coating etc are identical).
Bo

[Stu Ward]

What about the 5x powermate ?
This seems like a real option for planetary imaging ?

[Poita (Peter)]

The 2.5x and the 5x are the same price too.
They are both $199 for 1.25" and $319 for 2".