[AstroNet] Galileoscope discussion

Wed Mar 11 12:49:04 SAST 2009

Dear all

The reason why I mentioned the Galileoscope (for that matter the
Dobsonian is also a viable option)
is if you are doing outreach over a distance and you are human capacity
limited.
At University we have to teach and do research during the time we do
not teach.
The higher level students are also caught up full time in Masters or
Ph.D studies in Astrophysics.
We therefore do not have the capacity to send out Astronomers with
cardboard, glasses etc. to several groups of kids
at orphan homes or schools with hostels.
What we however do is to appoint student assistants to prepare school
level posters and
then buy several of these ready-to-use telescopes. These are then sent
to distant groups 
in several towns in the Province.
We identify a responsible person in the group who can accept the
telescope (with posters) and
then let the kids play and discover the nightsky with the telescope. In
this way we hope that seeds are planted. 

It is a gamble, but I am willing to give it a try.

We can also donate telescopes to the groups/schools which Kevin and his
co-workers already
reached, but I will first discuss this with Kevin.

Regards
Okkie de Jager

>>> "Johan Smit" <JohanS at firsttech.co.za> 2009/03/11 12:11 nm >>>

I agree with Rupert and Marciej.

To demonstrate the working of a telescope, I have used the following
parts:

For the objective lens:
My reading glasses of  +1.5 diopters strength. 
A diopter is the inverse of the focal length in meters.
Examples: +1.5 diopter is 1/1.5 = 0.667 meters; 2 Diopters is * = 0.5
meters; 1 diopter is 1 meter focal length.
Practically the range 1.5 to 2 diopters works very well*manageable
focal length.
If anyone in the eyewear lens industry can step forward and supply
really cheap (free preferably) lenses it will be much appreciated.
Otherwise teach the kids to strip their parents* reading glasses, but
do not blame the resulting fight on me.

For the eyepiece:
A small magnifying lens (also a positive lens) works remarkably well. I
use one with a focal length of about 50 mm.
The combination yields a magnification of about 5 to 10 times*I have
never measured it exactly, but it demonstrates to operation wvery well.
Shorter focal length lenses will obviously magnify more.

All you need to do is to devise a way to mount these two lenses at
opposite ends of any structure and a means to move them to achieve
focus.

Because only simple lenses are used the instrument does suffer from
various abberations, but works better than I imagined at first.
Higher magnification and shorter focal lengths increase the
abberations.

If any-one is interested in seeing my demo *telescope* contact me
directly on johans at firsttech.co.za
It was built from cardboard and sticky tape as Rupert suggested.
If you visit Scope-X on 30 may 2009 you can attend my talk where I use
this demo telescope. (http://www.scopex.co.za/)

Regards 

Johan Smit.

From:astronet-bounces at mail.saasta.ac.za
[mailto:astronet-bounces at mail.saasta.ac.za] On Behalf Of Maciej
Soltynski
Sent: 11 March 2009 11:09
To: astronet at mail.saasta.ac.za 
Subject: Re: [AstroNet] Galileoscope discussion

I strongly agree with Rupert. All that is necessary is the objective
lens and the eyepiece lens. The rest should be a project for the kids /
educator / interested amateur.

If money is to be spent for a complete optical system, then surely
binoculars should be considered?

Maciej

....

I think there is far greater reward in being able to "create" a  
telescope then to be handed it on a plate. Not only will kids learn  
about technical problems and that they are capable of solving it  
themselves but they may be inspired to go further, instead of  
believing that every thing comes from some far off land. Give them a  
lesson in the alignment of the optics and the only thing not readily  
available- the optics.
I am sure their are capable people in this mailing list who could  
build a telescope out of some cardboard or sticks and sticky tape! A  
tripod can be made from a string hanging from a tree, or three  
broomsticks tied together? ...

Rupert

Note:
This message is for the named person's use only.  It may contain
confidential, proprietary or legally privileged information.  No
confidentiality or privilege is waived or lost by any mistransmission. 
If you receive this message in error, please immediately delete it and
all copies of it from your system, destroy any hard copies of it and
notify the sender.  You must not, directly or indirectly, use, disclose,
distribute, print, or copy any part of this message if you are not the
intended recipient. First Technology Holdings and any of its
subsidiaries each reserve the right to monitor all e-mail communications
through its networks.
Any views expressed in this message are those of the individual sender,
except where the message states otherwise and the sender is authorized
to state them to be the views of any such entity.

Thank You. 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.saasta.ac.za/pipermail/astronet/attachments/20090311/bc485b61/attachment.htm>