The Portland daily press., 1877-10-31
Rare Event in Astronomy.


The planets Mars and Saturn, in which so
much interest has been centered the past season,
have been keeping up quite filtration, not
| withstandipg the many observers who were
constantly watching them. Both planets were
| quietly pursuing their journeys from west to
| east around the sun, until early in July, when
| the apparent motion of Mars began to dimin-
| ish, and on the 9th of 9uly the two planets
were in conjunction, Mars continued its mo-
| ton with diminishing velocity little further
toward the east and then stopped. After a
short rest this planet began retrogra1e motion
and again passed Saturn Aug, 18th, continuing
its course toward the west, for several degrees,
when it rested for the second time. 1t then
took up its original course from west to east,
and has continued it with increasing velocity,
SO that its change of position from one night to
another can now be easily detected This rap
id motion will on Saturday evening bring about
the last conjunction, which will be more inter-
esting than either of the others, from the fact
tnat the planets will be much nearer each other
than we have before seen them.
When we notice these curously irregular mo-
tons of the planets it is no wonder that the
ancieDts called them wanderers. for with their
limited knowledge of the planetary and stellar
systems, these motions were entirely unac-
countable. If any one to whom the motions
now seem strange will mark diagram, plac-
ing the Sun, Earth, Mars and Saturn, in their
relative positions and distances, these appar-
emily irregular motions will be shown to be
simple and regular. Let US make such dia-
gram and place the sun in the center, then with
radius of one inch we will draw circle for
the earth's orbit. Next draw the orbit of Mars
with radius of one and one-half inches Out
side of all describe the orbit of Saturn, with
radius of ten inches, now divide the diagram
like the face of clock, so that we can place
the planets in the proper places in their orbits.
We will place Saturn in its orbit at the twelve
o'clock point, and Mars in its orbit at quarter
past one, and our earth on the inner circle at
half past two. Our diagram will then Illus
trate the relative position of the planets Earth,
Mars and Saturn as they were situated last
June. Now draw line through Earth and
Mars and produce it to the orbit of Saturn
showing the relative position Of Mars and Sa''
turn as seen from our earth at that time.
A diagram of the above description was ex-
hbted in this Office last evening by Abner Low
ell, Esq. By it the positions of the planets can
be seen with great distlnctness. 1t should be
remembered that the motion of the planets is
in the direction opposite to the hands of watch
and that the angular velocity of the earth is
about twice that of Mars.
We will now move the earth in its orbit two
hours, or from half past two to half past twelve
These motions will have brought about the first
conjunction and carried Mars some distance to
the east of Saturn. Continue the motion of the
Earth and Mars as before and it will be clearly
shown that Mars will apparently come to Arrest
and then begin retrograde motion and make
another conjunction with Saturn and go past it
short distance and rest second time, and
then take up its original course rapidly and
make its third and last conjunction, which we
shall see November Sd.
Triple coniunctions between these planets are
quite rare, the last having occurred in 1879, and
the next one will not take place until 1916. It
should be borne in mind that these coniunctiors
are ia right ascension, and not necessarily in
declination at the time of conjunction the
two planets and the pole of the heavens are in
the same straight line.