Hi
My
name is Juan. I live in Gatineau, Quebec. And I have an small
observatory
100 Km North of Ottawa.
This
page is mainly dedicated to Astronomy under extreme
cold. Mel
Bartels telescope control system.
And
other bits and ends.
Update
Nov.
10, 2007
Last fall I embarked on Mel Bartels
telescope drive adventure.
It consist in a sophisticated stepper motor control program. That can
convert any telescope into an accurate GOTO instrument.
Given the rigors of Canadian winters and the fact that the scope sits
in an unheated observatory 100Km from home. I had planned on assembling
the project at a leisurely pace at home during the winter months. And
then.
Installing the system on the German mount at the observatory come
spring
time. There was no way that I was going to be caught tapping screw
holes
on metal in sub zero temperatures !...
Getting
there is half the fun !This has been a very mild winter.
But as luck would have
it. A cold snap decided to bring the temperatures down to -30C on
Friday
and -35C on Saturday ! The observatory is on top of a hill,
at the
end of a 1000 foot trail through the woods. Normally.
Transporting
all the equipment ( 2 desktop PCs, monitors, tools, etc.) would have
been
easy with the help of my small four-wheeler. But due to the extreme
cold.
I could not get the darned thing started. So I had to snow-shoe all the
equipment up to the observatory by pack sac.
But Hey
! What are we
?
Nerds ?
The installation actually went quite well ( I did not loose too many fingers). The only accident occurred when one of the Plexiglas boxes that I had built to cover the gearing mechanism. Fell off the edge of a chair. The face plate shattered as if it was made out of glass. Plexiglas don't flex too much at -30C.
While setting up the
connections for the ST-4. I placed
a mini screw driver between my lips...
INSTANT SEAL!!! I'm sure I
won't repeat that one again...
this winter!
(picture not available)
Last summer. I installed a quality sound system with home made speakers (my other hobby). Suddenly seeing took a beat. All stars had become pulsars. The low frequency sound waves were making resonate the large sonotube scope. You can actually stick your head in the scope and hear the base get amplified, some frequencies worst than others.The observatory
Roof
opening mechanism
Sliding weights on both the opening and
closing wires
are a must
in order to always maintain wire tension
for smooth winch
operation.
Why I don't suffer from differential flexure
The guide scope mount is made of oak and
is extremely
rigid in all axis.
My design philosophy was simple.
Not only should the guider mount not
depend on the main
tube for strength.
But it should actually add strength to the
main tube.
A good focuser mounting platform will not
only
reduce flexure.
But will also allow for easy
critical adjustment
of the focuser in all axis.
And as in my case. Solve vigneting
problems.( The hole
through the platform and the scope tube is now 3.5" diam).
Four aluminum straps tensed and bolted around the main tube. Provide further antiflexsure support. One at the mirror cell. Two at the scope cradle / guider mount intersections. And one at the spider mount. The later allows to tense the spider vanes at levels that would otherwise deform the tube into an square.
Results
The above shot of M13 was taken with Mel
Bartels
free telescope control program. As you can see. It is capable of very
accurate
tracking. But what is really fun is to click at an object on my PC
planetarium
and see the big telescope majestically slew to it with pin point
accuracy.
(for those that accuse cardboard tubes of flexure)
AURORAS
(click to enlarge)
