On 03/06/2011 07:56 AM, Bob Stricklin wrote:
OK you guys woke me up and you are full of humor.
I will throw out a topic.
What if you wanted to make your own telescope? Where would you find low
cost high quality lens or mirrors? Would you consider making the optics
by casting materials in a plastic membrane or spend the dollars to buy
them. Is there any military or other surplus worth considering?
I have a small ranch so away from city a bit and lots of room. I can
weld and have the equipment needed. I have access to large diameter used
steel pipe of most sizes at reasonable cost. I found this link on the
web while typing this posting and it took me away for a bit. Will have
to spend more time here too:
I could build it on a trailer so I could take it to star parties or I
could build a fixed installation.
Also have the ability and motors needed to build a tracking system.
This is something I have been thinking of doing for some time and it
will be a long term project.
I have Solidworks 3D software. So as ideas develop I can make a detailed
design. Also have optical simulation software to test ideas.
Questions that will likly come:
What will it be used for?
What is the budget if any?
I have many times tried to think of an economically
sound method to design a large reflector mirror and
here are some of my thoughts:
1) Does the base mirror have to be made of one monolithic piece?
The larger the radius, the harder it is to grind a perfect
parabolic shape. It also means bulk, mass and density is
harder to work with. It is said that the mirror base material
should be made of a material that have the least thermal
expansion coefficient and the mass should be dense enough
to prevent ground/air movements, or so I think.
2) Is it possible to design and create a segmented parabolic mirror
array so that thermal coefficients in each segment can be computer
controlled and the whole contraption suspended so as to reduce
Several options I could think in this area of would be:
a) A lightweight parabolic (honeycombed?) frame. What I
am thinking here, is the ability to dynamically and integrally
control the base mirror's overall focal point.
i. Normal "glass" polished mirrors, each segment shaped and
integrally added to the overall parabolic frame.
ii. A metallized (mirrored) mylar sheet with correct thickness,
overlayed and sealed to the parabolic frame. Behind each
segment could have computer dynamically controlled +/- air
pressure to change the focal points.
There is probably more we could add, but that's all I can think of for