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The construction of the telescope was largely
inspired by the book of Pierre Bourge, "My telescope and my
observatory, why not?". Mount with fork, tube octagonal,
drive by a sector and step motor. I bought the
mirror, ten years ago. It is one 8 inches . The focal distance is 1200 mm.
I am satisfied with quality and I did not seek to test it
(Foucault). I will make it when I will have time... This
telescope lived a time in the form of azimutal mount. When I decided
for an equatorial mount, the schedule of conditions was to be able to
pass from the latitude of the Metropolitan France, with that of New Caledonia and
the opposite after a two years stay, without remaking all mounting.
This basic concept being established, I excavated 10 minutes in
my garage and I brought out an old axis of a turn to grind , an end of pipe fixed on a saved turntable of the bucket,
plywood, and in one day, I constructed the first prototype. The
adaptation in latitude is done by the change of the adapter out of
wooden, between the axis and the foot column. The weight of
mounting is 37 kg with the fork and 12 kg for the tube. Thank
you Pierre Bourge for the great principle: Triangulation,
fundamental for stability. Metal poses problems of vibrations,
but wood generates inflections. All is business of compromise.
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The tube is octagonal. Construction such as
it is described in the book of Pierre Bourge does not pose really any
problem. It is one of the simplest parts. If one is
modestly equipped, it is possible to be made cut the boards to the
good dimension in all the stores of do-it-yourself. However, the
first thing that one to me says when it is seen it, it is that the
tube must be complicated to make. Its form and its quality of
construction confer a great rigidity to him. The access to the
accessories (enquiring...) is facilitated compared to the square tube.
Holding of the square tube assert that the air flow is better.
Can - to be. That remains to be shown and I do not know a
specialist in turbulences who leaned seriously on the subject.
With my opinion the difference between the two types of tubes
should not be a significant factor. Compared to a standard tube
metal worker, I find that it is easier to fix accessories, that
rigidity is better (that limits the problems of collimation) and that
the protection of the mirror is better. On the other hand should
be accepted a a little higher weight. My tube with the
finder, the barrel, the mirror, carries it ocular, (without
against the poids)pèse 12 kg. What remains reasonable.
With my opinion, painting for blackboard that one finds in all
the stores of do-it-yourself is what there is best for the interior of
the tube, to avoid the reflections. The barrel is made
completely according to plans' of P. Bourge. |
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I used a support of bar with curtain which one
finds in all good hardware and the absolute weapon that I use in much
situation, Adhesive Backed Teflon Tape.
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| The support is built on the model of that of the
site of Yves Lhoumeau (see links). the guidescope is a MEADE 60/700
. Once collimated with the telescope, it is
very practical to remain pointed with the webcam. |
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