Starry Skies Above Santa Monica

October 2-9, 2002

Mirek Plavec
Emeritus Professor of Astronomy, UCLA

   The Sun
   - A Bit Farther to the South
   On Sunday, October 6, the Sun will rise at 6:51 a.m., culminate at 12:41 p.m., and set at 6:30 p.m. Thus it gives us 11 hours and 39 minutes of sunshine, making the day shorter by 15 minutes compared to the preceding week.
   The Sun is still projected into the constellation of Virgo, but lower than before, more than 5 degrees below the celestial equator.

   Good-Bye, Goddess of Love!
   Venus has adorned our evening sky since February, but this “elongation east” is nearing its end. You may wonder why we call this position “elongation east”, when Venus is actually visible in the west after sunset. The planet is located to the east of the Sun, however, and this explains the term.
   The Sun, as I mentioned above, is projected into Virgo, and Venus shines in the next constellation of the zodiac, Libra (the Scales). Venus is now projected very low in the south for us: its position corresponds to the position of the Sun in December. The result is that for us, Venus sets fairly soon after the Sun: just one hour later, by 7:30 p.m.
   You know that, for rather a long time after sunset, the sky above the western horizon remains quite bright, so you will understand that even a very bright object such as Venus may easily be lost in that bright background, even if there are no clouds there. So, if you spot Venus low above the south-western horizon shortly after 7 p.m., say good-bye to that beautiful “evening star”!
   Thus, when the stars appear above you, there will be no bright planet among them. Two planets are actually fairly high in the sky during the evening hours – Uranus and Neptune. Both are projected into the constellation of Capricorn, but require at least binoculars to be seen – and also a good star map, since there are many real stars as bright as these two planets in that region.

   Two Bright Planets Later at Night
   Saturn appears above the eastern horizon shortly after 10:30 p.m. It is still projected into the edge of the constellation Orion – that short “peninsula” of Orion which actually divides the two adjacent constellations of the zodiac, Taurus (the Bull) and Gemini (the Celestial Twins). Saturn shines as an ordinary star of the first magnitude, and, in its vicinity, there are several stars that compete with it as to brightness. Preceding Saturn is the reddish star Aldebaran, the “red eye of the Bull” (Taurus). Below Saturn are two such stars in Orion, Betelgeuze (fairly close to Saturn), and Rigel, farther to the south.
   Jupiter is still a morning object, rising as it does shortly after 2 a.m. Jupiter is projected into the constellation of Cancer, which has no bright stars. The nearest bright stars are the two stars in Gemini, Castor and Pollux, preceding Jupiter in the sky, and then Regulus in Leo, which follows Jupiter. None of them can compete with Jupiter in brightness. The only competitor could be Sirius in Canis Major (Big Dog), which appears in the sky at about the same time as Jupiter, but lies much farther to the south.

   The Moon
   - Fading and then “Reborn”
   The New Moon comes on October 6. Before that Sunday, the very thin crescent of the Moon may be visible in the pre-dawn hours. On Wednesday, October 2, the Moon rises after 2 a.m., and shines fairly close to Jupiter. On the next morning, Thursday, October 3, the Moon passes above the first-magnitude star Regulus in Leo. The Moon rises after 3 a.m., and is a thin crescent – only 13 per cent of its disk will be illuminated.
   On the following mornings, October 4 and 5, the Moon will be passing above Mars and then above Mercury – but all these objects, including the extremely thin Moon, would be very, very hard to see.
   After the New Moon (October 6), the Moon will gradually reappear above the western horizon in the evening, after sunset. The first evenings are again not favorable, since the Moon will be very thin and very low in the southwest. Perhaps the first good chance to spot the crescent Moon comes on October 9, Wednesday evening, when 18 per cent of the lunar disk will shine. The Moon will then be located low in the southwest, above the reddish supergiant star Antares in Scorpius; it will set by 9 p.m.