Re: Why Longer Focal Length for Planetary?
- From: "Mark S. Holden" <mark@xxxxxxxx>
- Date: Fri, 15 Jul 2005 15:59:05 -0400
Bob May wrote:
Why use a 3mm effective EP to see the planet with good size when you can use something larger with a lot better eye relief? The powers used on the planets are usually up in the 300x and larger to get the planet to a ince disk. A 600mm focal length means that you need a 2mm EP to get that much power. Better to use someting much longer of a focal length so you can at least look into the EP.
-- Why isn't there an Ozone Hole at the NORTH Pole?
I agree with you, but this may change.
TMB hopes to bring out a TMB/BO 2.5mm planetary eyepiece with (iirc) 19mm of eye relief and a 58 degree afov. I'll be interested in trying one of these to see how it compares with using a monocentric with a barlow.
Unfortunately, a longer scope just isn't practical for me. (Back injuries, and portability issues)
.
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- Why Longer Focal Length for Planetary?
- From: Mij Adyaw
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