I'd like to know what the benefit in image quality would be between using a Televue 2.5x Powermate/9mm Nagler combination and using a high power eyepiece alone, such as a 4mm Radian? Does using the Powermate retain the Nagler's wide FOV? Hope someone can clue me in. Thanks.
Powermate vs. eyepiece only
Started by krellboost, 09/10/2003 08:28PM
Posted 09/10/2003 08:28PM
Opening Post
Posted 09/11/2003 04:03AM
#1
IMHO, you lose nothing when you put the 2.5x powermate in front of any ocular. As a matter of fact, you may actually gain something: a few extra $$$ in your wallet from not having to buy another premium eyepiece.
YMMV, my $.02 worth, in my experience, etc, etc, etc...
Clear skies,
Tom
YMMV, my $.02 worth, in my experience, etc, etc, etc...
Clear skies,
Tom
Posted 09/11/2003 04:54AM
#2
Yes, the afov of the Powermate-d eyepiece is maintained.
In terms of fidelity and critical low-contrast resolution, the Radian will have the advantage over the Powermated 9mm Nagler. -Not that the 9mm Nagler is bad, mind you -- it's just that the Radians are -- simply -- a *healthy* step ahead, in terms of planet-viewing fidelity.
The Powermate/Nagler combo *will* certainly be bulky and a bit ungainly, and would perhaps overwhelm a not-so-robust focuser.
If I were looking specifically for a 4-to-5mm "solution," I'd opt for the Radian (or another reputable planetary eyepiece). However, if I were shooting for a modular 2.5X accessory, the Powermate would be my choice.
Not sure if that helps.
Best wishes and luck, whatever your choice.
-Dan
In terms of fidelity and critical low-contrast resolution, the Radian will have the advantage over the Powermated 9mm Nagler. -Not that the 9mm Nagler is bad, mind you -- it's just that the Radians are -- simply -- a *healthy* step ahead, in terms of planet-viewing fidelity.
The Powermate/Nagler combo *will* certainly be bulky and a bit ungainly, and would perhaps overwhelm a not-so-robust focuser.
If I were looking specifically for a 4-to-5mm "solution," I'd opt for the Radian (or another reputable planetary eyepiece). However, if I were shooting for a modular 2.5X accessory, the Powermate would be my choice.
Not sure if that helps.
Best wishes and luck, whatever your choice.
-Dan
Posted 09/11/2003 04:59AM
#3
Yes, the Powermate will retain the Nagler's 82 degree apparent field of view, but of course it will be an 82 degree field on what is effectively a 9/2.5=3.6mm eyepiece, kinda like a 3.5mm Nagler.
The main downside is that you're talking about a 3.6mm eyepiece comprised of 11 optical elements in 6 groups, whereas a 3.5mm Nagler Type 6 would have 7 elements in 4 groups. An experience planetary observer should be able to see the extra scatter from the additional 4 air-to-glass surfaces in the combination with the Powermate, but the image should compare well in terms of sharpness, and probably most observers would not feel disadvantaged. The 4mm Radian will give a little bit less magnification and so might be preferable in some scopes for that reason at least.
--
Mike
The main downside is that you're talking about a 3.6mm eyepiece comprised of 11 optical elements in 6 groups, whereas a 3.5mm Nagler Type 6 would have 7 elements in 4 groups. An experience planetary observer should be able to see the extra scatter from the additional 4 air-to-glass surfaces in the combination with the Powermate, but the image should compare well in terms of sharpness, and probably most observers would not feel disadvantaged. The 4mm Radian will give a little bit less magnification and so might be preferable in some scopes for that reason at least.
--
Mike
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