Evening star. [volume] (Washington, D.C.) 1854-1972, 1877-09-11
THE MOONS OF MARS.
Something about Them and Their
Discoyerer.


creased Americas astronomical reputation
is Professor Assph Hail, OF the L. =. Naval
! Observatory, at Washing ton. who has just
achieved well deserved success in the dis
| cCvery OF The moons of Mars. Little, how
/ ever, beside the bare knowledge OF the dis
| covery and the name of the discoverer is
known outside OF scientific circles With a
| view OF learning some of the particulars OF
! Professor Halls success, a representative
TIKI STAR called upon him day or two ago,
] at the observatory. He found him surround
"a by books ana papers in his Office, sdi pin-
! ing the dome containing the mammoth Ell IA
| iorlal telescope. oue Is Immediately struck
win his pleasing and scholarly appearance
| He is som. what above the medium a. ght
with a large ard we'll propor iolted frame
/ Dy no means II Ginning 10 cOrpUlency, aud is
| apparently about forIy-Ssve1 wears of age
! his features are decided, the brow high aud
well arcbf 1, gray ls1- blue eyes remarkably
| clear and expressive; and dark hair and
beard. the latter IA her short. His voice is
pleas ing, his smile lights up his whole
face, and his laugh il hearty and joviaI
lie is a native OF Goshen, Connecticut.
men Old enough lie IL armed the ira lie of car
lenter, having a very meagre education
Later he married school mistress and N
was she WHO induced him TO study, aud her
self became his teacher. lie rapidly adj
vanced, Used his teacher, aud reached
the higher branches OF mathematics. He
became school teacher himself Tor a short
me. When about twenty Bve years of age
he obtained position IN the Harvard Cot
lcge Obst rVatory, and was reta ned there for
several years as assistant. While here he
first beca me known as an astronomer toy his
contributions To The Mathematical ReUieto.
Shorty after the astronomical activity of
The naval observatory here was revived in
1901 number of professors of the ma ~ were
appointed, aud Hall was given a position as
assistant. In 1853 he was promoted To be a
professor. Here he has remained ever since,
d hard worker. respecIC and appreciated by
his associates, who say he does not ap1ear
IN the least elated AT the triumph he has
labored SO hard for. His position CORES ponds
To The rank OF commander, his seniors being
Admiral Rodgers, superintendent OF the Oh
seryatory, and Professors Coli 1, Yaraal
AID Newcomb, ranking as captains. Pro
lessor Coffin will be retired on the 18Th inst
Professor Hall has had charge of the large
telescope since 1875, when ProfeSsyr New
como left II, 10 give his attention To some
theoretical Investigations.
PRELIMINARY TO THE DISCOVERY.
Professo Hall says that early last spring
he was impressed with the probability of the
existence Of a satellite 10 Mars, and deter
mined TO make a close search at the earliest
opportunity. 1t is well known no Y on the
night OF the nth of August he observed a
peated observations and measurements, the
discovery, OF not only one moon but Two
was COZ firmed. Between the 18th and the 10Th
when the weather was unfavorable for sue
ceS sful observations, he both hoped and
feared, but his wife, TO whom alone he com
municated his discovery, was enthusiastic
and confident. While impatientIy waiting
TO confirm his discovery his generous dispO-
sltiOn almost induced him 10 communicate
bis chances of success TO his associates SO
that all could share The honor, but the thought
OF lis many years OF labor, without any
"luck," convinced him that IL would be fool
ish 40 throw away his first real good chance
his discovery is OF great importance in
science; in fact II is inferior 10 only two an
the ceLIuIy, viz: the discovery of Sepiune
in lo46, by DR.. Gale, of Berlin, and that of
tpe ring OF small planets, or asteroids, in
1901, continued by Peters, OF Cliuton, y. Y.
and watson. OF Ann Arbor, Mich. : lrprise
is often expressed that the moons OF Mars
were rot discovered long ago, since they are
Row so easily visible.
WHY THE MOONS WERE NOT SOONER
FOUND.
Several good reasons account for the late
discovery-'he present position of Mars, the
PERFECTION of our large telescope, and the
energy, ability and shrewdness OF Professor
Hall being by no means the least important
Mars passed It's opposition on the night O
The 5th of september, and WAS thea ~ it,
uearest distance TO the eartn-abolt thirty
three million miles. Favorable OppOsitions
lko occurred in lsi5aIS in 1852, but Mars was
farther OIL then than now. The opposition in
1892 viii be as favorable for observing as the
present one. Previously, when lars was in
opposition, astronomers were devoIing all
their attention TO making obser vat ions to
determine its parallax, and hence the dis
t&Dce OF the sun, and also 10 make drawings
One astronomer, however, previous TO Prof.
stdICucu lOI d MOOu VI M4rk-D ARE ST,
in 1862 He, however, thought that il Mars
had satellite IL would bear the same rela-
ZION To the planet as our moon to the earth.
Consequently be searched too far of, and his
field OF observation did not include the SIS
pected satellite or satellites, and be was
therefore unsuccessful. Prof. Hall thinks
that II D'Arrest had polluted mis- telescope
nearer the planet be could cot have failed to
make the desired discovery And too the
largest and finest telescopes have only been
made since Mars was last In position TOR
SnnnQESfnl
newly discovered moons can now be seen
with an Indifferent telescope, il must be re-
menbefed that ii takes a much larger Ia.
sliument TO make discovery than To- see il
when II is known last exactly where to look.
The great object in having large telescopes
Is TO afford an abundance OF light, so That
faint objects as well as distant ones ca he
seen. II was principally for the purpose Of
observing closely the faint satellites of the
outer planets that the present large telescope
was constructed.
THE REPORTED THIRD MOON.
1T Will be remembered that DR.. Henry ORA
per, who has a private observatory at Dobbs'
Ferry, on the Hudson river claims TO have
discovered, in connection with Professor
Holden, a third satellite; the 9th or two q s.
covered by Prof. Hall being distinctly visi-
searchli several nights al the same time
with Dr. Draper, has failed to confirm the
discovery claimed by the latter. He does cot
say the third is not there but simply that he
is unable to find it, Mr.. S. W. Buruham, a
prominent amateur astronomer at Chicago,
who has very superior refractOr, reports
that he has been unable to find it. Hundreds
Oh telescopes all over the world are turned
upon Mars every clear night, and although
the two satellites discovered b. Prof Hall
are distinctly visible, no one has as yet con
frmed the claim of q thru. When DR.. Ora
per frs, claimed his discovery, it was deem
ed very pre- Sable for he has an immense re-
hecting telescope, little, IL any, inferior in
power TO the large refracIor here at the 90
servatory. DIR. Draper did not use this teie-
scope, however. when he claimed to have
found the third satellite, as il was rigg, for
pefiectiDg his recent important discovery OF
oxygen In the sun. The astronomer most
likely to see the third satellite, If ii exists is
MIR. l.. ]. Ellery, government astronomer
at Melbourne. He has an immense reflect
ing telescope, and Mars passes the meridian
nearer his zenith than ours.
TIE GREAT EQUATORIAL TELESCOPE
The famous 26 inch equatorial telescope,
VIII ch played such an important part in the
late astronomical success, was mounted in
1873, and was placed In charge OF Professor
Newcomb, and later OF Professor Hall The
tn be Is OF steel. One-sixteenth of an inch in
thickness near the ends, and one eighth in
a mi ddlo nd &c do ty,t