THE SOUTHWORTH PLANETARIUM
207-780-4249 www.usm.maine.edu/planet
<http://www.google.com/url?q=http%3A%2F%2Fwww.usm.maine.edu%2Fplanet&sa=D&sntz=1&usg=AFQjCNHulkHuLP13bOG2PkNrPazsGWFs2A>
70 Falmouth Street Portland, Maine 04103
43.6667° N 70.2667° W
Altitude: 10 feet below sea level
Founded January 1970
Julian Date: 2459272.18
2020-2021: XCVI
THE DAILY ASTRONOMER
Monday, March 1, 2021
March 2021 Night Sky Calendar Part I
Happy first day of March!
Although the date varies considering one's perspective, spring will begin
this month! The onset of the fairer season is a welcome occurrence to
many, even if the attendant onset of warm weather might be delayed by a few
weeks (months) depending on your location. Now that a new month has
begun, we offer our monthly night sky calendar. Ordinarily, we offer this
calendar in two parts. This month, however, we're dividing this calendar
into three parts due to the immense amount of information and graphics-
contained therein.
HAPPY SPRING!
Well, almost....
*MONDAY, MARCH 1: METEOROLOGICAL SPRING/ASTRONOMICAL WINTER CONTINUES*
If, sometime during the first three weeks of March, a Northern Hemisphere
dweller asks, "Is it spring, yet," he/she could receive two correct
answers. A meteorologist, after flashing a 100-lumens smile, would say,
"Why, yes, it is! Spring started on March 1st." An astronomer, after
flashing a 105.32 lumens smile -we win- would insist that "Well, yes,
actually, spring will not begin until the moment of the vernal equinox,
which this year occurs on March 20th."
According to the meteorologists, spring begins on March 1st; summer begins
on June 1st; autumn starts on September 1st and winter begins on December
1st.
This year, astronomically speaking:
- spring begins on March 20th
- summer begins on June 20th
- autumn begins on September 22nd
- winter begins on on December 21st
*TUESDAY, MARCH 2: MOON AT PERIGEE*
The moon travels along an elliptical orbit that is slightly elongated. (An
elliptical orbit that is not elongated is called a circle.) During each
orbit, the moon reaches a point of least distance (perigee) and a point of
greatest distance apogee). Today, the moon reaches the perigee of this
particular orbit. At the precise perigee moment, the moon will be 365,423
kilometers from Earth.
[image: moon_orbit.jpg]
The above image shows the moon's orbit as a highly elongated ellipse.
Here, one can readily observe that the perigee point is much closer to
Earth than the point of apogee.
[image: lunarorbit_graph2.gif]
The second image shows the moon's orbit (solid curve) relative to a perfect
circle (dotted curve). One can see that the moon's orbit only deviates
slightly from a circle. The moon's orbital eccentricity is 0.0549. Were
its eccentricity zero, the orbital path would be circular.
*WEDNESDAY, MARCH 3*:* FINDING LEO THE LION*
[image: Leo-finderV2-400x328-1 (1).jpg]
Leo the Lion becomes a prominent early evening constellation in late
winter. One can find Leo ascending in the eastern sky just after dark.
The Lion's 16-degree high "sickle" represents the lion's head and mane.
The southern sickle, star, Regulus, represents the lion's heart. One can
find Leo by looking "under" the Big Dipper's bowl, which will rise into the
northeastern sky early this evening. We'll observe Leo rising
progressively earlier each night through the spring and into summer. The
lion is part of the zodiac, meaning that the Sun appears to move through it
each year. The Sun passes through Leo from mid August to mid September.
*THURSDAY, MARCH 4: MARS NEAR THE PLEIADES*
[image: pleiades-nov-2018-Fred-Espenak-Arizona-e1542547236557.jpg]
Tonight one will see Mars "close" to the Pleiades Star Cluster, a misty
globule of faint light poised on Taurus' shoulder. Their apparent
proximity to one another is illusory. While Mars will be approximately
140 million miles from Earth tonight, the Pleiades' distance from us equals
441 light years. To put this difference in perspective, if Mars were just
one foot from us, the Pleiades would be 4,066 miles away.
*FRIDAY, MARCH 5: MERCURY 0.3 DEGREES N OF JUPITER (BRONZE EVENT!)*
The smallest planet -save Pluto- and the largest planet appear less than a
degree apart in the pre-dawn eastern sky this morning! Both bodies will
rise just before 5:15 a.m., approximately half an hour before the onset of
civil twilight. One will experience little difficulty distinguishing
between them as Jupiter (magnitude -1.8) will be slightly more than six
times brighter than Mercury. Jupiter appears much brighter despite its
considerably greater distance. Whereas Mercury will be 86.4 million miles
from Earth today, more than half a billion miles separates us from
Jupiter. We ascribe Jupiter's brightness to both its size (860 times
larger than Mercury in terms of surface area) and albedo, the ratio of
reflected-to-received solar radiation. While Mercury reflects only 14% of
all incidental sunlight back into space, Jupiter reflects about 53
percent. Although Jupiter is much farther away, it still shines much
brighter in our sky.
*FRIDAY, MARCH 5: LAST QUARTER MOON*
*SATURDAY, MARCH 6: MERCURY AT GREATEST WESTERN ELONGATION*
-When at greatest western elongation, an inferior planet will appear in the
eastern pre-dawn sky.
-When at greatest eastern elongation, an inferior planet will appear in the
western early-evening sky.
One will find Mercury in the eastern sky this morning. The first planet
will rise at 5:10 a.m.
*TUESDAY, MARCH 9: BRIGHT INTERNATIONAL SPACE STATION FLY-OVER*
[image: PassSkyChart2.png]
Watch the International Space Station traversing the sky before sunrise.
The ISS rises at 5:12:34 a.m. (at which time it will be passing directly
over Lake Superior). The station attains its maximum altitude of 69
degrees at 5:15:43 a.m. At this time, it will also attain its maximum
brightness of magnitude -3.8, making just about as bright as Venus. The
ISS will set in the southeastern sky at 5:21:08 a.m. During this
fly-over, the ISS will appear to move between the Big Dipper and Leo the
Lion; as well as across Bootes, along the northern tip of Ophiuchus and
just south of Aquila, the southernmost of the "Summer Triangle"
constellations.
*WEDNESDAY, MARCH 10: MOON, JUPITER AND SATURN WITHIN A CIRCLE 5.3 DEGREES
IN DIAMETER (SILVER EVENT!!)*
What better reason to awaken early today than to see the waning crescent
moon (8% illuminated) "close" to the gas giants Jupiter and Saturn.
The best time to observe these three worlds is after 5:15 a.m. One will
be easily able to distinguish between Jupiter and Saturn as the former will
be ten times brighter than the latter.
To subscribe or unsubscribe from the Daily Astronomer:
https://lists.maine.edu/cgi-bin/wa?SUBED1=DAILY-ASTRONOMER&A=
<https://lists.maine.edu/cgi-bin/wa?SUBED1=DAILY-ASTRONOMER&A=1>