The times. [volume] (Washington [D.C.]) 1897-1901, 1900-07-01

ing astronomers of America have taken
some remarkably clear photographs of the
moon, which prove beyond doubt that no
life exists on that satellite.
The next in Importance among the big
refractory telescopes is the Lick II should
here be explained that there are two dis
tinct kinds of Misrepresentation and
refiectors. In the FIRST Of these you LOOK
through q convex lens At q star, while in
the latter you merely see the reflection Of
the image in a concave mirror.
Many astronomers are Of the opinion that
the Lick telescope excels the Yerkes; it
certainly can boast of wonderful astro-
nomical record in the discovery OF new
celestial objects. Its success In this direc-
ton is probably explained in . large meas
ure on account Of Its unique position from
an astronomical point OF view The Lick
Observatory is on a high hill in California
TO wit, Mount Hamilton. where the at
mosphere is often better for observation
than at the Yerkes Observatory, near Chi
cago
When the Lick telescope was erected It
claimed the distinction OF being the largest
in the world. It's object glass measures
thirty-six inches. In size. therefore, ii is
only few inches behind its great rival,
the Yerkes.
This instrument is estimated to have
ever it may have cost 1t has undoubtedly
done some good work. Prof. Bernard,
probably the most indeiatisable astrono-
mer OF the day, made many notable dis
coveries with this instrument. Through IL
he discovered the new satellite of Jupiter.
Prof. Burnham. with the aid of this in
strument, made numerous measures" of
double stars. while he also discovered
quite a number OF new pairs. Undoubt-
edly the Lick telescope is the most pow
erful one. 1t apparently brings the moon
down to within seventy-fve miles OF the
earth and as an astronomer once re-
marked. 'the way it picks up stars is
caution"
There are many other large refractory
telescopes at the various observatories.
The one at Pulkowa, which has an object
glass OF thirty inches diameter, is a very
fine instrument. The one at Nice has also
thirty-inch object glass. and has done
some good work in the observation of the
planets and minor planets. The refractor
at Greenwich can boast OF q twenty eight
inch glass. 1t is undoubtedly fine in
strument but, like most Government OBJ
servatories, the astronomers at Greenwich
have given their attention to steady OBJ
servations rather than to hunting up new
stars, which our American cousins are So
fond of doing. The Paris and the Vienna
refractorS have both twenty-seven inch |
glasses, the latter especially being fine
telescope. 1t has discovered many new
minor planets. What these instruments |
have cost It is difficult to say. Many |
costly improvements have been made in |
several OF them, and it is doubtful IL |
check for s2,500O00 would purchase them. |
The Refractory Telescopes.
A word or two may be said about the
great refractory telescopes. They are I'M
loubtedly cheaper to build. An object
glass of eighteen inches diameter is worth
about $1,000. whereas mirror of the
same size costs about $500 ReGectors, of
course, are the older instruments Indeed,
he Galileon instrument, practically the
irst telescope used for astronomical pur-
)oses, may be said to come under this
read. In its day it made great sensa-
ion. for on the first night it was used
January Z. 1910. Calico discovered three
" Jupiter's moons.
One of the most rema, Fable reflectors
'ver built was Lord Rosse's great tele-
cope at Parsonstown, Ireland. II has