JAMESTOWN, N.D. (NewsDakota.com) – Of all the naked-eye planets known since antiquity, the most elusive is Mercury, the closest planet to the Sun.

According to legend, Nicholas Copernicus (1473-1543), the astronomer who revived the heliocentric theory of the solar system, never succeeded in viewing Mercury; on the other hand, I saw this planet with unassisted eyesight in downtown Philadelphia!

It is actually a rather bright body, but is doomed to compete with twilight because of its proximity to the Sun. Mercury is never more than 28 degrees in elongation from the star, which means it also rises or sets within two hours of the Sun. Worse yet, the planet’s image is rendered unstable by the refraction of its light by the Earth’s atmosphere near the horizon.

But this March, Mercury’s close proximity to Venus, the dazzling white “evening star” (and second planet from the Sun), will make it easier to detect. Once you’ve spotted Venus, use binoculars, field glasses, or opera glasses to find Mercury nearby; then try to detect the latter with the naked eye. Mercury has been described as white, yellow, or orange; it strikes me as yellow-orange.

Luckily, the area in back of Taber Hall and the Reiland Center has a panoramic view of Jamestown and the western sky; when I lived in campus housing, my children and I often went there to look for Mercury during its favorable evening appearances. Go thou and do likewise!

March 1 (Thur.): Full Moon, the first of two this month, occurs at 6:51 p.m. CST. At this time Luna will be 7 degrees above the eastern horizon, 32½ minutes of arc in apparent span, and 228,700 miles distant. It doesn’t qualify as a “Super Moon” this time because perigee (its closest approach to the Earth) took place on Feb. 27.

Look for Venus and Mercury at 6:50 p.m., a half-hour after sunset and just before the start of nautical twilight (when the sky becomes gray enough that sailors have trouble distinguishing the skyline from the sea). At that moment Venus will be 5.1 degrees above the WSW-W skyline; Mercury will be 1.73 degrees to its lower right. Venus (magnitude –3.9) will be then 10 arc-seconds across, 97.8% lighted, 67,423,540 miles from the Sun, and 154,373,570 miles from Earth. Mercury (at a magnitude of –1.3, 11 times fainter than Venus but still quite bright) will be 5.4 arc-seconds across, 91.2% lit, 29,135,230 miles from the Sun, and 115,604,490 miles from Earth. Both planets, emerging from behind the Sun, still are quite far from our world.

March 5 (Mon.): Mercury passed only 1.4 degrees north of Venus around noon today, but the two inner planets still will be close together tonight. At 6:57 p.m. Venus (mag. -3.9) will be 5 5/6 degrees above the WSW-W skyline, 10.1 arc-seconds in apparent span, 97.4% lighted, and 153,574,150 miles from Earth. Mercury (mag. -1.1), appearing a dozen times fainter than its neighbor, will be roughly 1.5 degrees above Venus, 5.7 arc-seconds across, 81.8% lit, 107,970,030 miles from Earth, and 29,153,820 miles from the solar disk.

March 7 (Wed.): At 2 a.m. the Moon, which will have risen 8 2/3 degrees over the SE horizon, will be 30.4 arc-minutes across, 70.2% sunlit, and 244,310 miles away. The bright beige “star” 4 degrees to its lower right is the largest planet of the solar system, Jupiter (mag. -2.2). At that hour the gas giant will be 39.8 arc-seconds in span, 99.3% illumined, and 460,114,885 miles from Earth.

March 9 (Fri.): Last Quarter Moon occurs at 5:20 a.m., when it will be 16¾ degrees above the SE horizon, 29.8 arc-minutes in apparent span, and 248,680 miles distant.

March 11 (Sun.): The Moon reaches apogee, its farthest distance from the Earth this month, at 4:14 a.m., when the two bodies will be 251,455 miles apart. At that moment Luna will be 29.3 arc-seconds across, 32.7% illuminated, and 23½ degrees below Jamestown’s eastern horizon.

March 12 (Mon.) Central Daylight Savings Time (CDST) begins at 2 a.m. on Sunday, but it probably would be easier to set your clocks an hour AHEAD before going to bed tonight. Remember the old rule, “Spring forward, fall back!”

March 15 (Thur., the Ides of March): Mercury (mag. -0.4) will attain its greatest eastern elongation of 18.4 degrees from the Sun around 10 a.m. today, so this would be a good evening to look for it again. At 7:11 p.m. CDST the planet will be almost 21.8 degrees above the western horizon, 42.9% lighted, 7½ arc-seconds across, 29,466,710 miles from the Sun, and 83,573,775 miles from Earth. Paradoxically enough, Mercury has become fainter even though it has moved closer to the Earth; its increase in apparent size has been cancelled by its decreasing phase, so that less of its surface area is sunlit. Dazzling Venus (mag. – 3.9), now 23.2 times brighter than Mercury, will be about 5 degrees to Mercury’s lower left.

March 17 (Sat., St. Patrick’s Day): New Moon takes place at 8:12 a.m., when it will be 10.6 degrees above the ESE horizon, 30.75 arc-minutes across, and 241,325 miles away. It’s passing several degrees south of the Sun this month, so no kind of solar eclipse will be possible. Mercury is passing only 4 degrees north of Venus tonight, so look for these worlds at 7:14 p.m, just as civil twilight is ending. At that time radiant Venus (mag. -3.9) will be 18.7 degrees above the WSW horizon, 96.1% lit, 10.3 arc-seconds across, 67,272,115 miles from the Sun, and 150,765,025 miles from Earth. Mercury (mag. 0.22), now 34.9 times fainter than Venus, will be above it; the innermost planet will be then 8 arc-minutes in apparent diameter, 34½% illumined, 30,182,750 miles from the Sun, and 78,473,290 miles from Earth.

March 18 (Sun.): Tonight the young crescent Moon joins Mercury and Venus in the western sky after sunset. At 8:15 p.m. the Moon will be 7.9 degrees above the western horizon, merely 2.67% sunlit, 31.2 arc-minutes in apparent diameter, and 238,030 miles away. 4 degrees to its right but slightly higher will be stunning Venus, now 95.96% lighted, 67,262,820 miles from the Sun, and 150,495,450 miles from Earth. Fading Mercury (mag. 0.44), now 39.8 times fainter than Venus, will be a little more than 4 degrees to its upper right. The smallest major planet of our solar system will be then 30¼% lighted, 30,591,755 miles from the Sun, and 76,075,030 miles from our home world. Hereafter Mercury will plunge rapidly back toward the Sun, passing between it and the Earth on April Fool’s Day and returning to the skies as a “morning star” later that month.

March 20 (Wed.): The Sun reaches the Vernal (Spring) Equinox at 11:15 a.m. today, ushering in spring for the northern hemisphere. This is a bit earlier than usual; normally the spring equinox occurs on March 21, but because of subtle variations in the Earth’s orbit it can take place a day earlier. In 2044 it will occur on March 19! Spring this year will last 92¾ days. Because the Sun rises almost due east and sets due west at the equinoxes, be careful driving along any roads with an east-west axis today!

March 24 (Sat.): First Quarter Moon transpires at 10:35 a.m., when Luna will be 32¼ arc-minutes across, 230,085 miles away, and 13.6 degrees below Jamestown’s NE horizon.

March 26 (Mon.): The Moon reaches perigee, its closest approach to the Earth this month, at 12:17 p.m. when the two bodies will be 229,352 miles apart. At that time Earth’s natural satellite will be 32.4 arc-minutes in span, 73% sunlit, and 16.6 degrees beneath the NE horizon.

March 31 (Holy Sat.): The second Full Moon of the month takes place at 7:37 a.m., making it the second and last so-called “Blue Moon” of 2018. At that time Luna will be 31.55 arc-minutes across, 235,295 miles distant, and 9¾ degrees below the western horizon.

Cover photo courtesy of NASA.