ATM Air-spaced Cooke triplet as eyepiece

["Pete Koziar" <pete.koziar@baltsun.com>]

Hi! I'm still working on a "copy machine" scope for my son (and to get
experience cutting threads for my own heliocal (sp?) focuser later down the
line). I've got a bag of "surplus" lenses from American Science & Surplus,
and want to do a simple eyepiece. It looks like there's a flint dcv lens in
the bag (the edge color has the greyish look of flint), so I'm tempted to
do an air-spaced Cooke triplet as an eyepiece (the alternative would be a
Ramsden or a Huygens without the flint element).

Does anyone have any design equations to use with this arrangement?
Preferably something easy to implement with a small lathe. Would it even be
a good idea? I have several small PCX crown lenses that I can use with it.

I'm hoping to beat the two "department store" scopes we've got around, at
least by a little bit (in only one of them you can actually tell that
Saturn has rings and isn't just an ovoid blob, and might even have a band
or two but that's all). The objective looks really nice with good color
correction, even though it's only 37 mm diameter and looks to be about an
f5 (it came out of a color copier that was junked). If I can get above 20x
with it, I'll be happy.

Then I just have to finish grinding the 5 inch f10 I'm working on. It's
taking FOREVER for that edge to fine-grind at 220 grit (two hours and still
going strong). I've still got about a quarter-inch ring of mega-pits left
from rough grinding, and am alternating MOT-TOT wets, and see at least a
little bit of progress. I'm hoping another hour or two should do it. If I
had it to do over, I would do more COC or W strokes at 80 before moving on.

Thanks to everyone for all their help in the past!

                    - Pete Koziar