The daily national Whig. [volume] (Washington, D.C.) 1847-1849, 1847-08-21
NATIONAL WING.
Fro- the Nantucket inqsirer'
THE GREAT TELESCOPE a. ga"
BRIDGE, MASS ~

IT. the Editor Of the Inquirer!
Permit me through the medium OF my
paper to make known the result :" z o.
ning's opportunity, which, on 'ne io'. 'a 90.
it was my rich privilege 10 enlp3, - IN
examination of various celestial OBJECTS WIN
the gigantic Equatorial Telescope recently
erect.d n the New Observatory al Jam
bridge. ,,:. u.,...,,,, 81
for several years past preparations have
h..n a nrooress at Cambridge for the noun
tins of this noble instrument, which, during
ths came neriod, has been in course OF con-
struction at Munich, in Germany. 10 view
Of the immense pains and cost involved, II
was an interesting and fearful question
whether its performance would equal the
= authorizations so long and anxiously lndu'-
ged by the parties interested and before
Speaking Of this, it may be useful briefly to
advert to some of its properties, though
far more extended and scientific description
of will doubtless be prepared by the able
director Of The Observatory, VIM. G. Bond,
and ultimately published by the committee
of examination,
The pier on which il rests is ofmasonry,
consisting Of blocks of granite. It is trus-
from Of cone, 20 feet in diameter at It's
base, aud 10 at its top, and 40 feet in height;
its base, however, is twenty feet below the
surface Of the ground. On its flat and Level
top is placed the pedestal, TO which the
telescope is attached. II is huge block
of granite, thirteen tons in weight, hand
somely wrought, and of construction
adapted TO the equatorial apparatus, consist
ING of ponderous masses of brass, and
weighing, with the tube, certainly not less
than four tons and yet SO lngenously and
perfectly is friction evaded, that the meresl
child can give it motion, and direct it 10
any point in the heavens. @~slt.
The object-glass Of the instrument is
fifteen inches in diameter in the clear; its
focal length is twenty-threr feet, and the
length Of the instrument, including the sill
ding tube, about twenty -four feet.
That the reader may not deceive himself
by comparing these dimensions with those
of the telescope constructed by Sir William.
Herschel, or the greater one more recently
made by Lord Rose, he may be reminded
that these are rejecting telescopes, with
metallic mirrors, and for equal duty, with
the exception Of what is termed space
penetrating power, must greatly exceed in
size. s,..s
Suffice it to say, then, that the telescope
a, Cambridge is Of the refracting kind, its
optical duties being performed by lenses ;
and to obtain a lens of fifteen inches in
diameter, of sufficient purity to represent
the object in perfect shape and color, under
high magnifying powers, is an art of incon-
ceiyable difficulty, and at present, believe,
has never been successfully accomplished
bv any other establishment than the one in
, which this telescope was manufactured
The secret was impaired by the lamenteo
Fraunhoffer, and SO fearfully tenacious are
they of the minuta of the movements thai
it il said they are unwilling TO use any
other poker to stir the melted mass than
that which was empioged by that ilustri-
Gus man. No larger refracting telescope,
has ever been in successful operation in
The world.
It is Of corresponding size with the
boosted instrument at the Imperial Obser-
vatory at Pulkova, manufactured at the
same establishment; but The Cambridge
lens is warranted 10 be as good, and by
the maker believed to be better. This was
also the opinion of Simms, the celebrated
manufacturer of England, who was en-
ployed to inspect the lenses, side by side.
The immense labor necessary in mounting
and adjusting an instrument Of this con-
struclion and magnitude, without previous
practice or experience, was greatly dimin-
ished by those preparations which The skill
and ingenuity Of the director enabled him
to effect, while the instrument and its vari-
Gus equipments were in Germany; but the
period since its arrival has not yet been
sufficient to render the adjustment perfect,
nor is it at present pretended to he fully
prepared for use. #.
To counteract the apparent durnal mo-
ton Of the celestial objects, which is con-
tinually throwing them out of the field OF
ordinary telescopes, "a great annoyance
especially when high powers are employed, J
q clock work is attached to the equatorial
axis, so constructed as TO give to the in
strument quiet and steady sidereak mo-
ton, contrary 10 the motion of the earth,
and which by slight modification may be
applied to the solar or lunar motion but
it is generally sufficient when adjusted to a
star. The effect Of this arrangement is to
keep the object for several hours constantly
in the centre OF the field of view.
The night Of the 18th was by no means
. favorable one. With the exception OF
scattering cirri, it was cloudess, but the
atmosphere was smoky, as it had been for
the previous fortnight. The first object to
which, at my request, the telescope was
directed was the planet Venus, invisible to
the naked eye, il being yet daylight. The
instrument was, however, adjusted to the
right ascension and declination Of the pla-
net, and the clock work Sc, in motion, when
the object made its appearance in the centre
Of the field, and, although yelled in smoke,
and obscured in daylight, il met the eve
with glare. What will be the effect of a
view of this planet in the absence of twi-
LIGHT. in a clear, autumnal EVENING cen