The daily union. [volume] (Washington [D.C.]) 1845-1857, 1847-11-23

complshed BY an ingenious continuance, which gives
motion to the eyepece instead of the telescope during the
sweep over any particular or belt The mcrometer
diaphragm for catalogung is provided with number Of
parallel wires the intervals of which have been care
fully determined and. by giving the eyepiece motion
made to cover belt Of from 4O to So broad in declina-
ton The nadr point being carefully observed the tee-
scope, chat of the mural Tor nstance being for the
belt to be swept, and all the microscopes carefully
read and recorded the observer takes his position at the
piece, and begins to it up and down. the in
strumen itself remaining fixed he reads it. In hat
ever part OF the field star appears micrometer wire is
close at hand $50 that there loss OF me with
single wire, In running the .mcrometer wire from one
edge OF the field to the oter and the star is blsected
with this nearest micrometer wire, while the time At
which ranss the several vertical wires also noled
The number OF the bisecng wire and the reading OF the
micrometer being entered the observation is COM
plee.
The observer thus keeps his eye at the telescope for
hours time, and under favorable circumstances can
observe with two three hundred stars during the
night The meridian crcE, II the same way, VIII occu
which the ingenuity of the astronomer has converted INTO
difference o-declinaon instrument, occupies the belt
above each instrument overlapping the belt of the other
by a or s. the stars in the parts thus overlapped being
common to two instruments: Thus, the meridian circle
and transit instrument establish the right ascension of
certain stars which are used by the mural so many
points of departures while the mural or meridian circle
establishes the declarations of certain stars which serve
the transit instrument as points OF departure for difference
of decnation This is the first sweep The next night,
ground the meridian circle covers the same belt to-
night which the former night swept by the mu-
raj Surprising the two nights equally favorable and
the instruments of equal powerthe latter OF which is
actually the case, the former sedOmall the stars that
in the first sweep, by the MURAL should be OBJ
served in the second by the meridian circle The two
lists Immediately compared, and should there be any
discrepancies between them the large equatorial is put in
pursuit of the peccant stars.
This great American work conemplaes the examna-
ton of every star down to the tenth magnitude not only
in the zodiac, but in the whole heavens; it includes
revision Of all the European catalogues and, while it
stars it also aims detect the disappearance Of any
known to existing catalogues In short, the Washington
catalogue aims at that degree of perfection, which, when
future astronomers shall find unknown star, may
justify the remark, this star in the heavens, be-
cause It is not in the Washington catalogue" Lieut.
Maury's original plan contemplated also measurements
for angle of position and distance of all double null
tpe stars together with accurate drawings OF all cus-
tiers and nebuB This to be the work of the equa-
toria but the undertaking to CLEAN after the merdional
instruments gives this telescope full employment for the
present.
The observatory commenced its operations in 1s45.
The first volume, quarto of five hundred pages, has
already been published and has elected many and high
Communications both at home and abroad. In the Opn-
ion Of of the most distinguished astronomers of Eu-
the front rank with the Oldest and best institutions OF
the kind in Europe. The volume for 1916 is in press
The catalogue for that year will number 200
Is 900 stars, most of them unknown to any existing
ogues the whole work will comprise aquarto volume Of
not less than 900 pages and will be the largest work
of the kind published by any observatory the
suit of single years labor.