, 1888-10-06

CJ ~ 49, "ANA AAS Wy AAbS u(SO
degree OF precision possible to modern
science, the position of the fundamental
stars with the RepSOld meridian CIRCLE
The time.service for railway use is now
conducted by Mr.. Hill Gate assistant to
Prof. Davidson), which leaves Mr.. Keller
free to make the necessary studies of the
great star spectrOScOpe, which il one OF
the most important accessories of the
36.inch equatorial. Mr. Barnard is asSidu-
OuSiy observing comets and lrebulie with
the fine 12-inch equatorial, and getting
the Photographic appliances in readiness
to be used with the greiFt telescope. He
has already discovered twenty new nebulB,
found i'll the course Of his sweeps for new
OmetS. To show you SOn9e Of the advan.
;tag6S of our situation here, | may tell you
that Prof. Swift, of Rochester, has a fine
Is inch equatorial by Alvan Clark, and
has discovered many faint nebHl@ by its
use. Two nights ago Mr.. Barnard. was
examining some Of these excessively faint
objects by means of the 12-inch telescope
(Which gives only u little more than half
the light OF Prot. Swift'S}, and in the field
OF view whore Prof. Swift had mapped OnlY
one nebula Mr.. Barnard found three
two being, of course, new. This is due
not only to the observers skill and keen
ness OF eye, but i'm great measure TO the
purity and transparency of our atmosphere
here.
"The Eastern astronomers lave given up
the observation OF Obj rS's comet, which
is now only about 400 as bright as last
year, but MIR. Barnard has succeeded in
following it up to last night, when 10
finally became too fBint to he seen even
here. These observations, which are several
weeks later than those Of other ObServa-
tories, are of real value, us they determine
4. IHnv,n c%n - NI,. ao.,A II: -l a
its motion to be fixed with a much higher
degree of accuracy. Mr.. Keeier is just
reducing his observations Of the faint
satellites of Mars, made with the large
telescope during the past months. YOu
can gain some sort of an idea of the
immense advantage of the great telescope
in such observations, when | tell you that
the brightness of the satellites as observed
by him was only about one sixth of their
brightness at the time of their discovery.
We can, then, make satisfactory Observa-
tons of objects which are sic times
fainter than those very minute satellites Of
Mars were when Prof. Hall discovered
them in 1877 with the great telescope at
Washington. l am becoming familiar with
the performance of the large telescope and
learning how to get the very best work
from it. 1t needs peculiar conditions; but
VIXEN all the conditions are favourable its
performance is superb. lam, as you know,
familiar with the action Of large telescopes,
having observed for many years with the
great refractOr at Washington, but | CON
TESS l was not prepared for the truly
magnificent action of this, the greatest of
all telescopes, under the best conditions. [
have had such views of the bright planets,
MARS and Jupiter1 OF nebul@, the Milky
Way, and some of the stars, as no other
astronomer ever before had. Jupiter, es.
p~ecially, is wonderfully full of detail that [
had not begun to see before. The
disks of his moons can be readily noted in
smaller telescopes; but here they are full
and round, like t~lOse-Of planets. | am al
most of the opinion that the curve of Ju-
piter's shadow might be seen on the sur
faces, under favourable circumstances,
when the satellites suffer eclipse. There
il reason to believe that the satellites Of
Jupiter, like our W moon, present always
the same face to their planet. This can be
studied here to great advantage if the disks
present any of the markings which are re-
ported by other observers.
"The Milky Way is a wonderful sight,
and I nave been much interested to see
that there is, even with our superlative
power, no final resolution of its finer parts
into stars. There is always the back
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