Evening star. [volume] (Washington, D.C.) 1854-1972, 1896-06-09
TO THE MOON, 80 MILES.
Such VIII Seem the Distance Through |
Paris New Telescope.
Paris Dispatch in the london Nsws

Paris Dispatch in the London News.
The huge block Of crystal which will be-
come the mirror for the great telescope
has safely arrived in Paris. If all goes
well the exhibition of 1900 will be able to
boast Of a distinct feature. Whether the
moons features will be equally distinct is
another question. Prof Loewy thinks not,
but M. Deloncle is still determined to carry
through his idea
THE moon one yard off," 1t was thus
the scheme Of the gigantic telescope was
spoken OF in the papers, but NJ. Deloncle,
however ambitious he may be in Central
Africa, protests that he never had SO pre-
poSterous a notion. He claims that it will
be possible to throw on to a screen views
of our satellite brought within a distance
Of thirty-eight miles. This remains to be
seen. However. everybody will wish NJ.
Deloncle. and still more especially his
shareholders, every success in what one
must still regard as an experiment.
The new telescope mirror is the largest
ever made. 1t was cast at Jeumont.
manufacturing place. and the last French
station on the line to Liege, Cologne, and
Berlin This splendid block of homogeneous
crystal weighs 5000 Kilograms. Its d.
ameter is 2.05 meters. and in its present
nearly rough state it cost $4,000 OF course,
1t was conveyed to Paris in a special train.
1t was wrapped up in heavy felt blankets,
protected by hoops Of soft wood, with
packed. the mirror was tightly wedged in
case that was placed in the wagon on
bed OF hurdles and layers Of hay.
For greater safety. the train stopped only
once, at Tergnier, and went at as slow a
pace as royal train escorted by railway
inspector. 1t was insured to it's full value.
The same afternoon it was removed from
the northern terminus to the workshop.
The mirror, before leaving Jeumont, went
through second grinding of its faces, be-
ing as smooth as a fine plate glass. But
Tor telescope purposes this sort Of smooth
ness is roughness itself. The finishing
process will take two years and six months,
and by more expeditions processes than
any hitherto in use. which, moreover. will
give greater accuracy than anything
known.
Hitherto astronomical mirrors and lenses
have been polished by hand by slowly rub
bling the glass with the naked hand, some
times, but not always, moistened with oil,
albumen and other substances which are
the makers secret The drawback of this
process Is that the mere heat of the hand
nay cause the surface to warp.
The new mechanical process, of which
particulars are not given will produce
surface approaching a true plane within
one ten-thousandth part Of a milimeter
Even this marvellous finish will leave a
margin, astronomers tell us, for errors
The whole finishing process will cost &c 600
Inc sllVering will not cost anything to
speak of.
The mirror will be mounted on two arms
len meters long, and will be set in motion
by machinery Of the usual sort. The rays
gathered from planetary space will be
reflected horizontally through a mammoth
tube sixty meters long, laid on piles of
masonry The lenses of flint and crown
glass will be one meter twenty-five cent?
meters, the largest in the world, and the
images, enlarged G.o00 times, Will be thrown
onto screen, which thousands of people
VIII view at time.
The moon will. If all goes well be brought
within thirty-eight miles, but it is most
doubtful whether images on this scale will
prove correct M Loewy, the assistant
director of the Paris observatory. who has
submitted some splendid photographs of
the moon, believes that the limit of ninety
lour miles he has reached is the utmost
prachcabie for long time to come. Larger
images will be indistinct