StarWatch: Moravian College Astronomy
MARCH STAR MAP |
MARCH 7, 1999: Mars in Spring Sky
- If you are glancing skyward around midnight, you may have noticed a bright
cream-colored "star" low in the southeast. That is the planet Mars. It will
be dominating our spring and early summer sky. Compare it to the blue-white
gem named Spica, brightest luminary of Virgo, the Virgin, twinkling about two
fists above and to the right of Mars. Marsí warmer color should now be a little
more obvious, and its steadier light is a dead giveaway that it is a planet.
Currently, Mars is about three times brighter than Spica. But by early April,
Earth will be coming around in its orbit towards Mars, getting ready to pass
the Red Planet on April 24. Marsí brightness will have soared to about eight
times that of Spica, and the widely separated pair should be readily visible
by 10 p.m. Throughout April, youíll also notice that Mars will be retrograding
or moving westward (backwards) towards Spica. An analogy to retrograde motion
would be a car moving in the same direction as your vehicle, being passed by you
on a highway. The car being passed will appear to move backwards with respect to
your car. The same thing will be happening to Mars because we are passengers
on the faster moving Earth! By early June, right after dark, Mars will be just
to the left of Spica and at the extreme end of its retrograde loop. The two
objects will appear to hang very close together for about the first two weeks
in June. Their closest approach will occur on the evening of June 9, but for
the first two weeks of June their separation will be within two degrees.
Retrograde motion is explained in more detail in the Nov. 29, 1998 StarWatch
column, which can be found at the web address below.
MARCH 14, 1999: Venus, Saturn, Moon Merge
- You may have begun to wonder if there are any other objects in the sky
besides the planets. We have been focusing on them for the past eight weeks
in this column. As these celestial wanderers revolve around the sun, they
shift eastward among the stars. It takes Mercury about 116 days to overtake
the Earth, and Venus nearly 584 days to accomplish the same feat. On the
other hand, Earth requires over two years to pass Mars twice, about 13 months
to catch up to Jupiter, and 12-1/2 months to rendezvous with Saturn. Like
pulling the lever on a one-armed bandit, youíre bound to come up with pay
back combinations where multiple planets are visible at the same time and
near to one another. This week, another lunar and planetary gathering will
be unfolding in the western sky after sundown. But instead of the very
close Venus and Jupiter embrace of February 23, Saturn will dance more at
armís length with Venus. Saturnís brightness will be meager compared to
the luminescence of Venus. Watch in the darkening west this week between
6:30-7:00 p.m. as Venus rapidly moves into position next to Saturn. By
Friday, Venus will be a scant 2-1/2 degrees to the right of Saturn. The
thin waxing crescent moon will shine below and to the left of both objects,
making this a tighter, but less spectacular coupling than the February 17-18
grouping of the moon, Venus, and Jupiter. The following evening the moon
will appear well above and to the left of Saturn and Venus. Good observing!
MARCH 21, 1999: Lore of the Blue Moon
- March 31 marks the second time this month that a full moon will occur,
and the second time this year that there have been two months with two full
moons. Refer to the Jan. 24, 1999 StarWatch found at the web address below.
The second full moon of a month is referred to as the Blue Moon. They occur
infrequently, about every 2-3 years, and hence the phrase "once in a blue
moon." However, the origin of the words, "Blue Moon," in reference to
astronomy seems to be strictly 20th century. First sited in print in the
Maine Farmersí Almanac of 1937, the Blue Moon there did not have the double
moon connotation. It surfaced again in 1943 and 1946 in Sky and Telescope
magazine articles. It was the latter citation that used the Blue Moon as
we refer to it today. Debra Byrd in 1980 used the Blue Moon in her public
radio program, Star Date, giving the term national attention. By 1985,
The Kidís World Almanac gave the astronomical term another boost. The
following year the Blue Moon was adopted for use in Trivial Pursuit. However,
when two full moons occurred in May of 1988, the international press spread
Blue Moon hype far and wide. The decade of the 1980ís ended with a New Yearís
Eve Blue Moon on December 31, 1990. In my personal library which contains
over 60 astronomical texts dealing wholly with the moon, only one mentions
a blue moon. And that was a real blue moon seen in Indonesia after a
volcanic eruption. Indeed, the origin of the Blue Moon seems to have
occurred right under our noses and within the last two decades.
MARCH 28, 1999: Moon Madness
- Iíd like you to participate in a little experiment regarding the moonís phases.
During the past week it was possible to witness the conspicuous brightening of the
moon as it headed towards its full phase. Sometime this week, the hemisphere of the
moon facing us will be completely illuminated by the sun. Iíd like to see if you
can tell on what night that will take place. There are many people who harbor the
notion that the full moon bewitches, and indeed, our language supports this notion.
Such words as "lunatic" and "lunacy" have their roots embedded in the moon, and in
the notion that the full moon spells trouble. "Luna" is Latin for the moon.
Hospital staff will swear that their patients are more restless on the night of
the full moon, and that there are more births which occur during this time period.
Police will also cite higher incidences of crime at full moon. All become
statistically invalid statements upon closer scrutiny. Visually determining the
time of the full moon is not an easy observation. For a period of about four to
five evenings the moon virtually appears to be full. During this stretch of time
the moon is also visible for most of the night. If something unsettling occurs,
and one happens to go outside, the moon will be readily visible if it is clear.
So instead of being able to pinpoint the event to the exact night of the full
moon, you have in reality, a much broader sweep of time to make the association.
Astronomically speaking, similar paranormal incidences should be transpiring when
the moon is new, but here again, there is no statistical verification. The answer
to when the moon was really full will appear in next weekís StarWatch.