The morning call. [volume] (San Francisco [Calif.]) 1878-1895, 1891-08-24
TIE MOON.
New Things Brought to View by
Astronomical Photography.

Astronomical photography has accom-
plished many wonderful results, but MOTH
ing. perhaps, more surprising thansirs dis
coveries upon the MOON The moon Is so
near by and has been so carefully studied
with the most powerful telescopes for hun
dredS Of years that the astronomers mad
come 10 think that they knew pretty much
all about it, or at least about that face OF
the moon which is turned toward the earth.
But it turns out that photography possesses
the power TO reveal things upon the moon
which cannot be seen by the eye, even with
the aid of the best of telescopes. A careful
study Of the negatives of the mo on, made
with the aid of the great Lick telescope, has
revealed the existence of many unknown
objects there, including great crater noun
tains and riffs or chasms in the surface OF
the moon, as well as some Of those mySterl-
Gus objects that go under the descriptive
name of bright streaks or rays.
Near the great crater, which we will call
Copernicus, another lcrater of nearly equal
dimensions is shown upon the mega tlyes,
although it is absent from the most elab-
crate maps of the moon, and cannot b seen
even with the Lick telescope except when
the magic eye of the camera, instead OF the
human retina, is applied to look for it.
When it is considered that this mysterious
crater represents the remains of mountain
ring more than fifty miles in diameter, it
appears exceeding strange that it should
escape detection by the telescope when
directed 10 the moon and yet be visible
upon a photograph OF the moon. The
reason appears to be that the walls of this
newly discovered crater were long ago de-
stroyed, being RACED by some denudtng
force nearly to the level of the surrounding
surface. 1t Is consequently but the remnant
of a gieat crater ring. Even in that condi-
ton, however, 1t would be visible to the eye
but for the fact that its huge neighDor, Co.
perncuS, whose walls are still standing 10
great height, is surrounded by enormous
masses of luminous material. which looks
like lava that must nave overlooked the sur
rounding country ages ago, and reflects back
the light OF the sun to our eyes with over
towering brilliancy. The glare of this
broad rejecting surface, covering hundreds
of square miles, is SO great as 10 conceal the
comparatively low relief of the broken
crater ring.
In fact, it Is mot improbable that Copper
nicus is responsible for the disappearance of
the other great crater, which doubtless WAS
the predecessor OF COperncus and once tow
cred up to an equal height above the sur
rounding plains. After 1t had ceased to be
an active volcano and CopernicuS had burst
forth. the latter probably overwhelmed it
with torrents OF lava, which, filling up the
space within its broken walls nearly TO their
new surface thus formed, SO that only the
summit OF its broken walls remains to be
caught by the acute vision of the photo
graphic plate.
In other parts of the NOON similar events
appear to have taken place, and there are a
number OF large craters, enormously greater
than any volcanic cTaterS upon the earth,
which seem to have been buried by the out
bursts OF lava from subsequently formed
volcanoes in their neighbOrhOod, so that
nly-t nf hair M 70 tal 10 Otx,
remain visible.
Another discovery, also arising from in
speetion OF the negatives made with the
Lick telescope, relates to the wonderful
system of bright rays surrounding the most
perfect crater in The moon, Tycho. This
extinct volcano is some fifty-four miles in
diameter, and is surrounded on the outer
side of its lofty walls by a comparatively
level region, some twenty-five miles broad,
of much darker hue than that OF the crater
itself or of the surrounding country beyond.
The hundreds of great streaks which rsdi-
ate from Tycho like the spokeS of a wheel,
varying in width from ten to twenty or
thirty miles, and in length from few miles
TO nearly 2000 miles, have always appeared,
when viewed with q telescope alone, 10 take
their rise from tue outer edge of the dark rim
surrounding tho crater, but the Lick mega
lives show that some of the StreakS at
least pass through this dark rim and extend
clear up to the very walls OF the crater. The
suggestion that these mysterious Streaks had
their origin in the volcanic energy of Tycho
when it was still an active crater is strength
ened by The evidence that the streaks actu-
ally reach 10 the crater itself.
These discoveries are likely to give re-
newed interest to the study of the moons
surface, ana while it is perhaps too much TO
expect that great deal of light will be
thrown by astronomical photography upon
the question whether evidence oil the present
or former existence of life upon the moon
can be detected from the earth, yet there
can be no question that new method OF
attacking the many problems that still re-
main to be solved concerning the character
and condition of our satellite has been
placed within the reach of astronomers