Starry Skies Above Santa Monica
February 14-21, 2001

Mirek Plavec
Emeritus Professor of Astronomy, 
UCLA

   Sun, Moon and Planets
   The Sun will cross the boundary between Capricorn and Aquarius on February 14/15, and from then on, it will travel upward through Aquarius (the Water Bearer). On Sunday, February 18, it will pass, at the local noon, very close to the zenith of Lima, Peru.
   For us, the Sun will culminate 45 degrees from the zenith, which is exactly half-way between our zenith and our southern horizon! And it will culminate 7 minutes after 12:00 on our clock -– this deviation is caused by the somewhat irregular motion of the Sun, while we must keep a regularly flowing clock time. The Sun will rise at 6:34 (a gain of 7 minutes per week) and set at 5:40 p.m (7 minutes later than a week ago) – for net gain of 14 minutes of daylight time.
   The Moon starts the Mirror week in its Last Quarter phase on the evening of February 14. If you look at the sky before dawn near the end of that night (14/15), you will see the Moon above the planet Mars, and both will be located close to the claws of Scorpius. After that night, the Moon will rise later and later, changing into a thin crescent with its illuminated part facing the east, until it disappears near the Sun. The New Moon phase will come on the night of February 22/23.
   Venus, in Pisces, reaches its greatest brilliancy (astronomically speaking, its magnitude will be -4.6) on February 21. Venus, in Pisces, is still very prominent every evening, visible fairly high above the western horizon already by 6:10 p.m. or so. It shines quite long, and sets by 9:00 p.m. If you compare the time of setting with the previous Sunday, you will notice that Venus sets 5 minutes earlier than last Sunday, while the Sun sets 7 minutes later. The fact that Venus is returning to the Sun (as seen in our sky, i.e. diminishing its angular deviation eastward of the Sun) is beginning to show, albeit not yet significantly.
   When the sky gets still a bit darker, you will have no problem in finding the bright Jupiter so high in the sky that you will think that it is nearly overhead. Saturn, fainter (but still first-magnitude "star") is not far to the west of Jupiter. The two planets are highest above the south already before 6 p.m., so when you are able to see them, they will be already above the south-west, but high up in the sky Both planets now move eastward among the stars, but at a snail’s speed, so you will find them pretty much at the same place where they have been for weeks. Currently, they are fairly close to each other, Jupiter still between the Pleiades and Aldebaran, and Saturn not far from Jupiter, a few degrees to the west. It is the motion of the Earth, as reflected in the apparent motion of the Sun, that changes their visibility: shortly after midnight, they set in the west. 
   The only planet visible in the morning hours is therefore Mars, which rises deep in the southeast just about at the time when the two big planets set in the west. It shines as a star of the first magnitude, with a distinct reddish hue. In its eastward motion on the stellar background, Mars is close to the "claws of Scorpion". The best time to see and identify Mars comes in the wee hours of Thursday, February 15, when the Last Quarter Moon passes above the planet.

   Zodiacal Light
   The moonless evenings of this week offer you a fairly rare opportunity to see the zodiacal light. By the "zodiac," traditional astronomy means a belt 8 degrees wide on both sides (northern and southern) of the ecliptic, which is the apparent path of the Sun among the stars. If the term "zodiac" sounds to you a little bit like "zoo," you are on the right track. The term can be translated as the "circle of animals," but by the "circle" it means the 12 "sun signs," or 12 constellations, through which the Sun appears to move during one year. The name is far from fitting, since out of the 12 constellations, only 7 bear the names of animals (Aries = the Ram, Taurus = the Bull, Cancer = the Crab, Leo = the Lion, Scorpius = the Scorpion, Capricorn = the Sea goat, and Pisces = the Fishes). You will certainly not include Libra (the Scales) or Virgo among the animals!
   Anyway, forget about mythology and let’s look at the western sky after sunset! The Sun sets (on Sunday) by 5:40 p.m. For a certain time after sunset, you can still read under the open sky, and you don’t have to have your car lights on; this "civil dusk" lasts till 6:05. The western sky still remains fairly bright, but the bright arc descends to the horizon and fades, and by 7 p.m., all trace of it disappears -– we say that the "astronomical night" has begun.
   However, the sky above the place where the Sun has set is really not completely dark. If the weather is favorable, and if you are watching the western horizon from a dark site -– say at or above the seashore -– you will notice a gentle cone of light rising from above the place where the Sun has set, and pointing to Venus. It is about as bright as the Milky Way in late summer – not too faint, if you watch from a dark site and if the Moon does not interfere. This is why the forthcoming evenings are so favorable!
   Since this luminous cone actually traces the ecliptic, or zodiac, it got the name of "zodiacal light." This light is actually the light of the Sun scattered by millions of tiny dust particles (we can call them tiny meteorites) that surround the Sun, and are visible only on such favorable occasions as are the moonless hours of the late winter / early spring evenings.