Re: [ATM] Lenses for 2" Super Plossl Eyepiece?

["Robert Mohr" <rmohr@tiwcorp.com>]

Hi David,

I've made a bunch of eyepieces with lenses I've gotten from Surplus Shed. Also lenses are 
available from others, such as Edmund Optical (a bunch more expensive)

You can get a real nice plossl with 2 identical achromatic lenses. For something in the 50-60 
MM FL range, you would want lenses 30-40MM in diameter and 100-120MM in focal length. 
You can also vary the EP Focal Length by increasing spacing between lenses.

Surplus Shed also has in their catalog something they call a 5x Achromatic Magnifier. This is 
actually a 53MM Plossl without the normal barrel, so may work well to be bolted into the 
scope you are considering.

Hope that is of use!

Bob Mohr

> Hi again folks:
> 
> Per my previous posts, and with your suggestions, I'm making good progress
> on my design for an inexpensive public terrestrial scope, and now I have a
> question about eyepieces.
> 
> If I use an 80mm. objective with a 900 mm. focal length and a 2-inch Meade
> 56mm. Super Plossl eyepiece, I'll get a magnfication of 16X with excellent
> eye relief and a wonderfully large eye lens to look through. For a public
> terrestrial scope, I think the view would be awesome. When using my Nexstar
> 11 GPS for low power deep sky viewing, an old-style 56mm. Meade Super Plossl
> is, in fact, my favorite eyepiece.
> 
> I can by a new one from telescopes.com for $89 with free shipping, but
> because I'm going to remount the optics in a weatherproof housing of my own
> design, I'll throw away everything but the glass. My question is, in hopes
> of saving some money, does anyone on this list know where to buy just the
> lenses (i.e. a "lens set") for this eyepiece, or if not these identical
> lenses, the lenses to make a 2 inch Plossl eyepiece with a focal length in
> the same ballpark?
> 
> Dave Sleeter/Moreno Valley
> 
> 
> 
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> ATM mailing list http://www.atmlist.net/
> 



Robert Mohr
Director of Technical Services
TIW Technology, Inc
rmohr@tiwcorp.com
See our web site at www.tiwcorp.com
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