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Re: [ATM] lensmaker for a very long focus objective
Unfortunatly this was probably one of the people responsible for the demise
of the optical shop in the "new"planetarium. I do not feel compelled to
help these people ,they seem to be more interested in showing people
science fiction and "flash" than anything to do with observational
astronomy.
A far better display would be to have an actual telescope (refractor, if
you will) set up for public viewing of the sun or planets.
There are two master opticians that they put out of work and they know
their names and how to contact them if they want someone badly enough.
David stevens
Peter Abrahams
<telscope@europa. To: atm@atmlist.net, bstephenson@adlernet.org
com> cc:
Sent by: Subject: [ATM] lensmaker for a very long focus objective
atm-bounces@atmli
st.net
03/26/2004 12:09
AM
The Adler Planetarium in Chicago is looking for a craftsman to fabricate an
objective lens, about 100 feet in focal length. It would be a singlet,
aperture perhaps 4 or 5 inches.
They have a small budget, but if they could afford a professional, they
would have hired one.
There is one unusual benefit to the craftsman to this project; this work &
your name will likely survive as long as western civilization does.
Director Bruce Stephenson bstephenson@adlernet.org has been
communicating with a historical telescope email list. Here are excerpts
from his emails:
----
As part of a new permanent exhibition at Chicago's Adler Planetarium, we
want to construct an aerial telescope for museum visitors to look through.
....museum visitors today (especially young museum visitors) want to do
more than look at things in cases.
The aerial telescope idea is an extension of this thought. It's an
attention-getter, an "attractor" in museum-speak, something that will bring
people over to see what it is.
For practical reasons it's unlikely to be moveable. We just want to show
people that it was possible to make a telescope without a tube that works,
and that they can look through to see a magnified view of, say, the Sears
Tower.
If it is feasible to make one of these, we would probably want to use it in
the daytime to look at a fixed target, fairly low in the sky since that's
where all the fixed targets are.
We will attach the objective to a flagpole or something. An existing pole
is 100' from a likely viewing area, so I suggested an objective with 100'
focal length.
......the eyepiece removable (when no facilitator is available to show
people how to use it).
One of our points will be that this kind of instrument suffered from many
deficiencies, which is why reflectors took over in the 18th century.
I'm about ready .....commissioning an ultra-long focal length objective
lens. (If we can afford it, of course. I have no idea what the cost would
be.)
Given all the uncertainties, perhaps the best approach would be to ask
anyone who might be interested to contact me directly. - Bruce
----
I hope the ATM list has room for any discussion on how to make such a lens;
but proposals should be emailed directly to Bruce.
--Peter Abrahams
=============================
Peter Abrahams telscope@europa.com
The history of the telescope and the binocular:
http://home.europa.com/~telscope/binotele.htm
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