Which is Brighter,sharper??

I have a 9mm Wide angle EP. I if I were looking at buying a 4.5mm EP, is
the image quality the same as using my 9mm with a 2X barlow?

Brian

On Sat, 26 Mar 2005 20:04:46 -0500, "Amyotte"
wrote:

I have a 9mm Wide angle EP. I if I were looking at buying a 4.5mm EP, is
the image quality the same as using my 9mm with a 2X barlow?

Brian

The old theory was that a barlow and a lower power eyepiece worked
better, because:
-The barlow lessens the need for highly corrected eyepieces with some
scopes.
-The slightly larger lenses in the lower power eyepiece are easier to
fabricate to a higher quality.

I don't know if either of these is true, but if the eyepiece you're
using is a "standard" kind with limited eye relief, you will be
happier using the eyepiece/barlow and it's inherently longer eye
relief that squinting through a 4.5mm eyepiece.

Lastly, the idea of viewing planets (which I assume is what you want
the higher power for is to limit the amount of glass in the optical
train to preserve the highest contrast. In that case, the higher
power eyepiece is a better idea (though less comfortable) than the
lower-power eyepiece/barlow combination.
-Rich

Amyotte wrote:
I have a 9mm Wide angle EP. I if I were looking at buying a 4.5mm EP, is
the image quality the same as using my 9mm with a 2X barlow?


I'd be concerned about eye relief. Unless you get a 4.5mm eyepiece of
noticeably superior quality with long eye relief and wide AFOV, you
might find you're better off with the barlowed 9mm WA. Double the power
without changing the eye relief.

-Stephen