ATM Fw: re BBC Rough Science/building a reflector telescope

["Bob May" <bobmay@nethere.com>]

Got this interesting little note from this guy for a TV show and my response
is below.  I'd consider that he'd love to hear from some of you guys on the
subject if you have any good ideas in this area.
From: Milla Harrison <milla.harrison@bbc.co.uk>
To: <bobmay@nethere.com>
Sent: Tuesday, May 06, 2003 10:04 AM
Subject: re BBC Rough Science/building a reflector telescope


> Dear Mr May,
>
> I'm sorry to approach you out of the blue, but I'm hoping you might be
able
> to help me with something?
>
> I'm producing a BBC science television programme called Rough Science - we
> take 5 scientists and put them in a "rough" location, and set them a
series
> of
> science challenges which they have to complete in 3 days (and there are 6
> programmes in the series). This year we're heading for southern
California,
> and basing the challenges around a "space" theme.
>
> We want one of the challenges to be about building a reflector telescope
> from scratch. I am hoping that you can advise me on how easy and realistic
> it is to build one?  The scientists will only have basic tools and at this
> stage I need to find out what raw materials they will need in order to
build
> an affective telescope.  We also want them to build, if possible, the
> mirrors for the telescope using local natural materials.  Is this
possible?
> ie can one extract silver oxide from rocks, which is needed to coat glass
> that we've provided?  What other chemicals would they need?  How easy is
it
> to do this?  Can you put me in touch with anyone that specifically makes
> mirrors from scratch?
>
> Their task, once completing the telescope, would be to calculate the
height
> of a mountain on the moon. Is this an achievable task with a 'home-made'
> telescope?  Can the scientists measure the distance to the moon?  What
other
> things might they be able to do?
>
> If it's easier for you to discuss this all on the phone then perhaps you
> could let me know a good number and time to call you (bearing in mind that
> the time zone difference means that your morning works best for me)?
> Alternatively, if this isn't really your area of expertise I would be very
> grateful if you could suggest someone else I could contact?
> I look forward to hearing from you at your earliest convenience.
> Many thanks.
> Best wishes,
> Milla Harrison
> Assistant Producer, Rough Science
> Tel: +44 0208 752 4183
> Fax: + 44 0208 752 7534
> email: milla.harrison@bbc.co.uk
> Rm 2318, White City
> 201 Wood Lane, London
> W12 7TS
> BBCi at http://www.bbc.co.uk/

Milla, that will be an interesting project!
For history, John Dobson (founder of the San Francisco Sidewalk Astronomers)
is probably one  of the people that you will want to talk with on this
subject.  He is the originator of the Dobsonian   telescope, probably the
easiest to build telescope at the present.  He is also a bit of a character
and is about 75 years old or so so he would be quite interesting to put on
the show.  I might also note that he was on a PBS Nova series (the first of
the series as i recall) on astronomy and telescopes.  Sorry that I don't
remember the series name but I do sort of remember that it was 6 shows.  The
thing I really remember is his kicking the base of the tube to get the
mirror to settle into the right position.
As a contrast to John, there are a number of people that are professionally
building telescopes on the west coast that would enjoy being on such a show.
They would all be an interesting contrast to John as the precision side of
things as opposed to John's flair.
Sounds like you are doing a scientific style Junkyard Wars as a spinoff of
that wonderful series.
FWIW, three days is more than enough to do a scope in a good size.  John
Dobson and crew, including spectators, did a 10" mirror in one day and had
it ready for viewing that evening.  Doing a mirror in one day is quite
possible and building a whole telescope could be done on Junkyard Wars if
the guys doing it were experienced in pushing glass.
As to measuring mountain heights on the Moon, that is something that won't
be really possible as the distance is just too much to determine something
like that.  Better would be to set some object to be discerned as to whether
it exists or other such chore.  Something like getting a photo of Polaris
and proving whether it is a single star or a double or some other star in
the polar area.  There are several doubles in that area that can be a fun
job for a 6" or so telescope.  I'll note that I used a 6" telescope that
hadn't been silvered to split the Double Double star system in Lyra.
Another fun one that will take a larger scope (in the 16"-20" size) and dark
skies would be seeing the star in the middle of M57 which caused that
nebula.   If you are lucky, there may be some nova or supernova that could
be visible in a 6" or so scope or a comet that could be a target.  For a
comet, you can really do some interesting stuff by determining the orbit of
the comet (you are working with scientists, aren't you?) and discuss the
problems in finding the orbit with just a few days of observations and how
it takes sometimes months to fully determine the orbit of a comet along with
the possibility of that comet hitting the Earth.
As to getting silver and other chemicals out of the ground and actually
silvering the glass, that will be a bit difficult.  Silver is pretty much a
difficult element to get out of the ore although there are places in the
Rockies that it is a lot easier than most to get the silver out.  Better to
go through one of the silvering processes from chemicals from the chemical
store.
As to using sand to do the grinding, this could be done but the grinding
rate will be a lot lower and the 3 days would probably be needed to do that
mirror.  Better would problably be to give them a pound of 80 grit and let
them seperate the finer grits from the results of the previous grinding.
This will teach the seperation of particles by size by the process of
waiting for the stuff to sink to the bottom of the container and recovering
the size you want.
All in all, the idea is quite possible and not hard to do and there are a
lot of little side jobs that need to be done by the crew, teaching a lot of
basic mechanical science at the same time.

Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net