Mineral Point tribune. (Mineral Point, Wis.) 1869-1938, 1877-10-03
THE DISCOVERY OF MARS'S MOONS.
What Professor Hall thinks Of DIR. ORA.
per's Alleged discovery.

spring he was impressed with the prob
ability of the existence of a satellite to
Mars, and determined TO make Il close
search at the earliest opportunity 1t
is we'll known how on the night OF the
18th of August he observed a strange
object near Mars, which after repeated
observations and measurements, the
discovery of not only one moon but
two, was confirmed. Between the 18th
and the 10th, when the weather was
miayorablc for successful observations,
he both hoped and feared, but his wife,
to whom alone he communicated his
discovery, was enthusiastic and conf
dent While mpatiently waiting to con
firm his discovery his generous DISPOSE
ton almost induced him TO communi-
cate his chances of success to his asso-
ciates, so that all could share the honor,
but the thought of his many years of
labor without any . luck convinced
him that it would be foolish to throw
away his first real good chance. His
discovery is Of great importance in
science; IN fact it is inferior to only two
III the century, namely, the discovery
of Neptune in 1916 by DR.. Gale Of Ber-
lin, and that of the ring Of small plan
cts, or asteroids, in 1891, continued by
Peters Of Clinton, n. y, and Watson of
Ann Arbor, Michigan, Surprise is often
expressed that the moons of Mars were
not discovered long ago, since they are
now so easily visible.
Several good reasons account for the
late discoyery-thc present position Of
Mars, the perfection of our large tele-
scope and the energy, ability, and
shrewdness Of Professor Hall being by
no means the least important. Mars
passed It's opposition on the night of the
9Th of September, and was then ut its
nearest distance to the carth-about
thirty-thrcc million miles. Favorable
oppositions also occurred in 1915 and
1862, but Mars was farther oil then
than now, The opposition in 1892 will
he rs favorable for Observing as the
present one Previously, when Mars
was in opposition, astronomers were de
voting all their attention to making OBJ
servatiunS to determine its parallaX,
and hence the distance of the sun, and
also to make drawings one astr0nu-
mcr, however, previous to Professor
Hall searched for moon Of Mars
ID Arrest in 1862 He, however, thought
that if Mars had Il satellite it would bear
the same relation to the planet as our
moon to the earth. Consequently ne
searched too far off, and his field of OBJ
servation did not include the suspected
satellite or satellites, and he was there
fore unsuccessful. Professor Hall thinks
that if D'Arrest had pointed his tclc-
scope nearer the planet he could not |
have flilcd to make the desired discov- |
cry. And 600, the largest and finest !
telescopes have only been made since |
Mars was last IN position for successful |
observations Although the ncWly-dis- !
covered moons can now be seen with |
an indifferent telescope, it must be re-
mcmhercd that it takes much larger |
instrument to make discovery than |
To see it when it is known Just exactly |
where to look. The great object in hay |
ing large telescopes is to afford an album /
dance of light 50 chat faint object, as
we'll ~ distant ones can hcSccn. Ii was /
principally for the purpose of observing /
closely the faint satellites of the outer (
planets that the present large telescope /
WAS constructed.
1t will aforementioned that Dr. Henry !
Draper, who has 81 private observatory |
ut Dohhs Ferry, on the Hudson River,
says lac has discovered, in connection |
with Professor Holden, third satellite: |
The other two discovered bv Profcs>orI
Hail. being distinctly visible mt the samci
time. Professor Hall, however. search !