Starry Skies Above Santa Monica

February 6-13, 2002

Mirek Plavec
Emeritus Professor of Astronomy,
UCLA

   The Sun – A Bit Friendlier to Us
   On Sunday, February 10, the Sun will rise at 6:43 a.m., and set at 5:32 p.m. Compared to the preceding Sunday, we gain 5 minutes of daylight in the morning, and 7 minutes in the evening. If you compare the differences with respect to 12:00, you will find 5 hours 17 minutes of daylight before 12:00, and 5 hours 32 minutes of daylight in the afternoon. The discrepancy is due to the fact that the Sun culminates 7 minutes after our clock time of 12 noon. We cannot follow the small variations in the motion of the Sun, caused essentially by the mildly eccentric orbit of the Earth about it, and our time must run uniformly – as a consequence, the Sun does not culminate exactly at noon on most days.
   Astronomically speaking, the Sun is now traveling in front of the stars of Capricorn. The astrological “sun signs” are actually those constellations through which the Sun appears to move during the year. If you were born this week, and if you are interested in astrology, you will know that your sun sign is Pisces, the Fishes. Some 2,500 years ago, the Sun was indeed projected into that constellation, but -– as a consequence of a phenomenon called precession, hated by astronomers and ignored by astrologers — the positions of the Sun have shifted by just about one constellation, so that your actual sun sign is Capricorn – don’t worry, it is completely irrelevant which sun sign you prefer!

   The Moon – Actually Very Little of It
   The Moon will at first show up only in the morning hours, then disappear completely. The Last Quarter was on February 4. After that, the Moon is a morning object, its illuminated part shrinking day after day. The New Moon will occur in the morning of February 12. In the following week, the crescent Moon will be fairly impressive in the evening.

   Two Planets Close to the Sun: Mercury and Venus
   Mercury will continue to precede the Sun in the morning, rising about 80 minutes before the Sun on Sunday morning. However, this is not a good apparition, Mercury is deep in the southeast, and not bright enough to be easily seen.
   Venus is very bright, setting after the Sun in the early evening, but is located, in space, almost behind the Sun from our point of view. Although it travels in its orbit pretty fast, about 35 km/s, it will take some more weeks before Venus becomes easily visible as a beautiful Evening Star. However, the situation is no longer quite hopeless even now. Venus, in Aquarius, now sets 30 minutes after the Sun. By that time, the sky above the southwestern horizon will still be fairly bright (due to the scattering of the rays from the Sun in our atmosphere), but Venus is such a bright object that it might be visible, very low above the horizon, for some minutes around 5:50 p.m.

   So Now We Actually Have Four Evening Planets
   Venus has just joined Mars, Jupiter, and Saturn, and will soon dominate above them. When that time comes, however, Mars will be disappearing in the west. Mars now shines only like an ordinary first-magnitude star. However, it moves through the constellation of Pisces (the Fishes), and in that region of the sky, there is no competing star, so Mars is still fairly conspicuous as the only brighter star adorning the evening sky in the west. Mars now sets shortly before 10 p.m.
   The two big and bright planets, Saturn and Jupiter, shine now high above the eastern horizon in the early hours of the evening. Saturn culminates high above the south already before 7 p.m., so, later in the evening, you should look for it to the west of the meridian. Saturn is not a striking object, unless you look at it through a telescope and admire its beautiful rings. To the naked eye, it appears as just an ordinary first-magnitude star, perhaps somewhat yellowish if you can recognize its color. You can identify Saturn without difficulty thanks to the fact that it forms a nice, fairly close pair of bright stars with the reddish Aldebaran in Taurus. Saturn has been receding (moving westward with respect to the stars), but it will halt that motion on February 8, and after that, it will resume its regular, albeit slow, eastward motion with respect to the stars, and slowly recede from the proximity of Aldebaran.
   To the east of Saturn, you will find the much brighter Jupiter, currently the brightest object in the evening sky. After dark, Jupiter already shines high above the east; it crosses the meridian just before 9 p.m., and after that, you should look for it to the west, but high in the sky.
   The only real star that can compete with Jupiter in brightness is Sirius, located much farther down in the southeast, if you look early. Sirius culminates above the south around 9 p.m., and after that, it is visible in the south-west for most of the night.