Focus on the planets

Mercury makes a brief appearance on the west-southwest horizon as February opens but drops from sight by week’s end. Look for the innermost planet very low on the horizon for an hour after sunset.

Venus remains high on the southwestern horizon at sunset where it gains in brilliance throughout the month. Venus is visible for about three hours as the month opens but this will shorten in preparation for its spring appearance as the “morning star.”

Mars rises after midnight on the southern horizon where it grows noticeably brighter as spring approaches. The Red Planet will give a dazzling performance by mid-June.

Jupiter dominates the evening southwestern sky where it is located between Aldebaran and the Pleiades star cluster. Viewers with telescopes should have no trouble picking out the Giant Red Spot and the major Jovian moons.

Saturn follows Jupiter into the night sky and is located to the gas giant’s immediate lower right. Saturn’s rings are tilted by more than 20 degrees offering an additional treat to telescopic viewers.

Uranus and Neptune are both lost in the sun during February.

Pluto is in the constellation Ophiuchus where it will require luck, a large telescope, and a finder’s chart to spot it.

Our Celestial Neighborhood

Last month, I discussed the fact that the change of seasons has more to do with the tilt of the Earth with respect to the sun than with the distances separating the two bodies. A reader wrote to ask if we would have seasonal changes if the Earth had no tilt, i.e. if the poles were perpendicular to the sun.

The short answer is that there would be no seasons but temperatures would be different depending upon your location on Earth. There would be 12 hours of daylight and darkness every day everywhere on Earth. The sun would always rise to the same height at noon and provide all areas with a constant amount of heat.

This does not mean that all areas would be exactly the same temperature; the equatorial regions would be the hottest and the poles coldest. It does mean that any given region would have constant temperatures except for minor variations due to changing orbital distances from the sun. University of Maine astronomy professor Neil Comins has described what an Earth without tilt would be like in his book, “What If the Moon Didn’t Exist?” If you have a question, write to me in care of the Bangor Daily News or e-mail at cgmewood@aol.com.

February events

1 Sunrise, 6:55 a.m.; sunset, 4:43 p.m. Moon in first quarter, 9:02 a.m.

2 Look for a close pairing of Jupiter and the moon tonight. Saturn is to the moon’s right and Aldebaran to its left. This is Candlemas, or Groundhog’s Day, marking the midpoint between the winter solstice and spring equinox.

3 Venus shines high in the southwest tonight. Mercury is far to the lower right low on the horizon. Fomalhaut is to Mercury’s left and may be mistaken for the inner planet. On this date in 1966, the Soviet spacecraft Luna 9 touched down on the lunar surface where it spent three days sending back photos.

7 The moon is at perigee, or closest approach to the Earth, tonight. This event, coupled with the imminent full moon, can give rise to very high tides.

8 Full moon, 2:12 a.m. The full moon of February is called variously the Wolf Moon, Snow Moon, or Hunger Moon.

14 Valentine’s Day.

15 A great day to catch three of the naked-eye planets. At dawn, the moon is very close to orange-red Mars well up on the southern horizon. Then, in the evening, direct your attentions toward the southwest, where Jupiter and Saturn are grouped with Aldebaran and the Pleiades. Moon in last quarter, 10:25 p.m.

16 The sun enters Aquarius on the ecliptic.

18 The sun enters the astrological sign of Pisces but astronomically has just entered Aquarius. The difference is due to a phenomenon called precession.

23 New moon, 3:22 a.m.

26 Note the pairing of the thin crescent moon with Venus tonight.

27 Jupiter, Saturn, the moon, and Venus form a rough diagonal line in the west early this evening.

28 Sunrise, 6:15 a.m.; sunset, 5:21 p.m.