November 13, 1998
3. Although the moon will be at full phase this morning at 9:19, you should wait until evening to enjoy the beauty of the most northerly full moon of the year. The moon will rise amid the stars of the constellation Taurus the Bull. By morning, the moon will have moved to a position between the horns of the bull and very near the bright star Aldebaran. The moon and Aldebaran will repeat this trick on December 30.
8. The moon gets underfoot tonight as it passes near the star Regulus in the constellation Leo. Leo resembles a lion if you can see the entire constellation, with Regulus near its front paws. Regulus is easily identified as the period to the inverted question mark that makes up the front end of the lion. By tomorrow night, the moon will be near the hind paws of the lion.
10. The moon passes the third-quarter mark in its monthly orbit around the Earth at 11:53 this morning. Your best view of the waning moon is after midnight; the last quarter moon is highest above the southern horizon near dawn.
11. As the moon wanes, it rises later each night. By tomorrow morning, moonrise will be near 2 a.m. when it will rise with Mars. Mars and the moon will brighten the backdrop provided by the constellation Virgo with a nice conjunction.
17. Although one of the closest planets to Earth, Mercury is one of the most difficult to see because it is always so close to the sun's position. This week might provide a better-than-average chance to see Mercury, as the winter ecliptic juts above the horizon in advance of the sun, placing Mercury at least 10 degrees above the horizon before sunrise. This morning, the waning moon is even closer to the sun and to the east-southeastern horizon.
18. Our calendar, based in the traditions of western culture, is driven by the motion of the sun. Calendars originating with tropical cultures pay a bit less anxious attention to the sun's motion and concentrate on the regularity of the moon's cycle. The moon is at new phase this afternoon at 4:42, marking the beginning of a new lunar month for many traditional calendars. The months of the Islamic calendar, for example, begin when the first sight of the young moon is possible, typically a day or two after new moon phase. Thus, the evening of Dec. 20 will signal the start of the holy month of fasting, Ramadan.
21. Is it midwinter, or is it just the beginning of the northern winter season? Our nomenclature and calendar reflect two different traditions. The ancient British calendar, which divides the year into eight periods, places the beginning of the year at Halloween. The year began on that date, halfway between the equinox of autumn and the winter solstice. For astronomers, the solstice marks the beginning of the sun's return to the north. We may have weeks of winter left, but at least the solstice at 7:56 this evening tells us that a little more sunlight will come our way each day.
23. There were many beautiful manned space flights in the 1960s, perhaps none so lovely as the Apollo 8 mission in 1968. This was the first manned spacecraft to orbit the moon, and the crew was still in space as Christmas Eve approached. Their words and view of our beautiful planet provided a very poignant moment in a turbulent year.
24. Will Santa have an extra moment as he flies his global mission tonight? If he does, he might want to check out a conjunction between Jupiter and the waxing moon. The pair will liven up the background in the constellation Aquarius until they set around midnight. The closest approach of Jupiter to the moon's position won't take place until daylight on Christmas day.
26. The moon is at first quarter phase this morning at 4:46. You'll have a better view of the waxing moon this evening when it will be well above the southern horizon. The moon is flanked this evening by Saturn to the east and Jupiter to the west.
27. Saturn and the moon provide most of the interest in an otherwise unbusy part of the sky this evening. Saturn is about 2 degrees north of the moon this evening, situated in the zodiac constellation Pisces.
30. The moon will be extremely close to the brightest star in Taurus tonight, brushing Aldebaran by about half a degree. This conjunction will take place in the late afternoon, so they should still be well-positioned when they become visible after sunset.
31. We'll all have an extra second with which to contemplate the closing year. The international time services will delay Coordinated Universal Time for one second between 23:59:59 on December 31 and 0:00:00 on January 1 of the new year. Our international time services tick out 24 hours of 3600 seconds every day, with seconds calibrated by unchanging atomic clocks. Earth, however, is slowing down and needs a bit more than that established total of seconds in a day; about every 18 months, an extra second is inserted to keep our super-accurate clocks close to the time standard that really matters -- the rotation of the Earth.