Sacred monuments

The Great Pyramid of the pharaoh Khufu or Cheops is truly one of the wonders of the ancient world. It has a square base of 756 feet on a side, is 481 feet high, and covers 13 acres. The Greek historian Herodotus wrote that it took 100,000 men more than 20 years to build while working during the months of the flooding of the Nile. It was completed about 2600 B.C.

Besides being the burial tomb of Cheops, the Great Pyramid also had a number of astronomical functions. One shaft from the king’s chamber pointed toward the star Thuban, in the constellation of Draco the Dragon. Thuban was the polar star, analogous to Polaris, at the time the pyramid was built. Another shaft from the king’s chamber was aligned with the transit across the sky of the three prominent stars of Orion’s belt. A shaft from the Queen’s chamber was oriented to Sirius, revered as the wife of the god Osiris. Sirius was of particular astronomical importance to the Egyptians because its heliacal rising signaled the annual flooding of the Nile River, an event crucial to the survival of the agricultural nation.

Focus on the planets

Sky watchers hit a planetary bonanza in March, with all five of the naked-eye planets known to the ancients on display in the evening sky.

Mercury comes into view in late March on the western horizon. Mercury peers just above the horizon at twilight on the 22nd, with a slim crescent moon to its upper left. A week later, Mercury is well up on the horizon at the same time, affording the best view of the elusive inner planet for the year.

Venus is located halfway up the western horizon around sunset. Venus will shine so brightly that it could actually cast a shadow in a darkened area with some reflective material such as snow.

Mars may be found to the upper left of Venus and is now so far distant that it will appear as a tiny orange-red dot even with a telescope. Orange Aldebaran, slightly to the upper left of Mars, could be mistaken for the Red Planet unless you check to see which one twinkles.

Jupiter rises in the east about sunset and steadily climbs higher as it remains in view throughout the night. March will be one of the best times during the year to examine surface features of the gas giant by telescope.

Saturn is high in the west after sunset, nestled at the feet of the twin stars of Gemini and high above Orion. Its rings are still tilted to allow for maximum differentiation.

Neptune and Uranus are just starting to emerge from morning twilight and will not be visible until later in the year.

March events

1 Sunrise, 6:14 a.m.; sunset, 5:22 p.m. Look for bright yellow Saturn to the lower right of the moon tonight.

6 Full moon, 6:16 p.m. The full moon of March is variously called the Sap Moon, Lenten Moon, Worm Moon or Crow Moon. Note brilliant Jupiter to the upper right of the moon.

11 The sun enters Pisces on the ecliptic.

12 The moon is at perigee, or closest approach to Earth, today. If you see the pre-dawn moon today, the orange star to its lower left is Antares.

13 Moon in last quarter, 4:02 p.m.

15 The Ides of March, not a great day for Julius Caesar.

17 St. Patrick’s Day. The Almanac says its time to plant your peas!

20 Spring or vernal equinox, 1:49 a.m. This is the time when the sun crosses the equator into the Northern Hemisphere. The sun is entering the astrological sign of Aries even though, astronomically, it is still in Pisces. New moon, 5:43 p.m.

22 The thin crescent moon is on the western horizon about 40 minutes after sunset. Mercury hovers above the horizon to the moon’s lower right while Venus blazes high above. Mars is to the upper left of Venus with the Pleiades tucked in between.

24 The moon is to the immediate left of Venus tonight.

25 The thickening crescent moon hovers very near Mars tonight. The bright star to their upper left is Aldebaran.

26 Saturn, the moon, Mars, Venus, and Mercury form a diagonal line across the horizon, starting with Saturn very high in the southwest and leading down to Mercury just above the western horizon.

27 The moon is at apogee, or farthest distance from Earth, today.

28 Moon in first quarter, 6:48 p.m. The “star” directly beneath the moon is Saturn.

31 Sunrise, 5:19 a.m.; sunset, 6:01 p.m.