Worcester Democrat and the ledger-enterprise. (Pocomoke City, Md.) 1921-1953, 1921-11-12

scale, DR.. Robert williams Wood of
Johns-H Hopkins had built a practical
concave-mirror telescope on Long
Island by rotating a basin of mercury
until the liquid metal shaped itself into
the proper concaSdty. There are
limits to its use, however. according
to astronomers, II the attempt is
made to build thes abandoned mine tel
escope.
The greatest telescopes now in use
times as great as that of the unaided
vision. This is only when the state
of the atmosphere is at its best. Or
dinarily astronomers have to be con-
tent with much less. sometimes with
q magnitication of 200 or 800.
"The atmosphere fixes an outside
limit of magnitica;tion," said DR.. Frank
Schlessinger, director of the Yale OBJ.
servatOry. "Lir1itLess magnifying
powers could not be used. Telescopes
will probably be made larger than at
present for use on mountain tops and
GSUcCldlly luNVIdDlE DuI Lie
tendency is to lose In distinctness as
magnifying power increases. Event
ually the object gazed on becomes
blur. as If seen through a heat haze.
Only through great instruments like
that at Mount Wilson, and then only
under most favorable conditions have
objects magnitied as much as 5000
times been seen with an unblurred
vision.
II Mars We're Mile Away.
The mine telescope, II 1t met the
sanguine expectation Of 1t projec-
tor, would magnify 25o00,O00 times,
which would bring Mars OFFICIALLY with
in a mile and half Of the earth. At
first thought this would seem to give
the astronomers a sight Of Mars equiv
alent to that which en air pilot OBJ
tains of the earth as he flies mile
and half above It. At that height
an airman could see cities, towns and
individual buildings, farms, orchards
and a thousand marks Of the activity
of man. Under the same advantages
an astronomer would soon know all
about Mars, where the creations Of in
telligent beings are believed to ex-
list on a much graItder scale than on
earth.
But here difficulty arises. The
airman Is unconscious Of the rota-
ton of the earth, because gravity pulls
the earth and air and the alrplane
with a uniform motion. On the other
hand, if Mars were brought within
mile and a half of the earth it would
be whirling so rapidly that the fea-
lures Of the landscape, would be lost
to the eye, as are markings on the
propellers Of an airplame revolving at
full speed.
If magnifEcation Of 25,00OO00
times or anything like 1t could be ac-
complished the observer could only see
a small patch Of Mars. Mars rotates
its 12,000-mile circumference once in
little more than "a hours, so that
at its equator 1t is making speed
of about ten miles minute, or about
five times the speed of a racing car.
If the observers were content with see
ing Mars Is miles off. the portion WIS.,
ible to them would still be streaming
past the telescope at the rate Of a
mile n minute.
A camera Of instantaneous action
might take pictures at this speed on
earth, but 1t could not be made on
Mars. A magnifcation Of 25,00oO00
times would mean that the light Of
Mars would be diluted to one twenty
five-millionth part of its brightness in
the sky, which would not be adequate
for rapid-fre photography or even for
ordinary vision.