Sacred monuments

Near the Nile River lies a temple complex called Karnak in what was once ancient Thebes and is now modern Luxor. The great Temple of Amun or Amen-Ra was a principal focus of Egyptian religious activity for millennia but what makes Karnak of particular interest is the controversy over its use.

The British astronomer Sir Norman Lockyer visited the site around 1890 and was struck by an immense corridor that ran the length of the complex. Lockyer believed that it was aligned westward across the Nile River to the midsummer sunset around 4000 B.C. It was quickly pointed out, however, that hills across the Nile from the temple blocked out any view of the setting sun, throwing the theory into doubt. Another astronomer did some quick calculations and found that the corridor only matched up with the sunset in 11,700 B.C. Even the Egyptians were not building temples that far back in time.

Lockyer’s reputation was such, however, that his book, “The Dawn of Astronomy,” is still in print today. Gerald Hawkins, whose name is forever linked with Stonehenge, solved the mystery of Karnak. He pointed out that an axis runs two ways and that if one looked east rather than west, it lined up perfectly with the midwinter sunrise of about 2000 B.C. Hawkins said that the eastern horizon would have been of greater significance to the Egyptians as the heliacal rising of Sirius, associated with the annual flooding of the Nile, was observed in this direction. In 1989, the American astronomer Ronald Reese photographed the midwinter sunrise as the sun momentarily stood over a massive gate at one end of the corridor axis.

Focus on the planets

September opened with a spectacularly close pairing of Jupiter and Venus in the southwest after sunset. Mercury may be glimpsed low on the predawn eastern horizon as the month opens but then disappears shortly thereafter. The bright star below Mercury is Regulus. Venus blazes in the southwest an hour after sunset where it is in very close proximity to dimmer Jupiter. They are closest on Sept. 1 with Jupiter slowly moving away as the month wears on.

Mars rises on the eastern horizon about 11 p.m. as September opens and then earlier each night throughout the month. Mars will double in brightness during September and this fact, coupled with its distinctive reddish hue, allows for easy identification. The only remote chance for confusion is the red star Aldebaran to the far lower left of Mars.

Jupiter opens the month in an extremely close conjunction with much brighter Venus as darkness falls on the southwest horizon. Venus then begins to pull away from Jupiter as the latter sinks lower on the horizon and sets earlier each night.

Saturn starts September high in the east about 45 minutes before sunrise. On Sept. 14, Saturn is close enough to the Beehive Cluster for both to be visible in the same field of vision with binoculars or a small telescope.

Uranus is nestled among the stars of Aquarius the Water Bearer where its faint green disk may be found with the aid of the finder’s chart published in the June issue of Sky & Telescope.

Neptune is in Capricornus where its bluish disk may be spotted using the finder’s chart and a medium telescope.

Pluto, as is nearly always the case, is a lost cause.

September events

1 Sunrise, 5:57 a.m.; sunset, 7:13 p.m. The moon is at apogee, or farthest distance from Earth today. Don’t forget to check out the spectacular conjunction of Jupiter and Venus tonight.

3 New moon, 2:45 p.m.

6 The southwestern horizon is a busy place about a half hour after sunset as Venus, Jupiter, Spica and the shadowy crescent of the new moon are all in close proximity.

11 Moon in first quarter, 7:37 a.m.

14 Look for Saturn very near the Beehive Cluster in the southwest during the early morning hours.

15 Venus, Jupiter and Spica make a triangle in the southwest about half an hour after sunset.

16 Moon at perigee or closest approach to the Earth. The Sun enters Virgo on the ecliptic.

18 Full moon, 10:01 p.m. The full moon of September is called Fruit Moon but this year, being the full moon closest to the autumnal equinox, it is also the Harvest Moon.

22 Fall or autumn equinox, 6:23 p.m. This is the point at which the sun crosses the equator and enters the southern hemisphere. The sun enters the astrological sign of Libra but, astronomically, has just entered Virgo.

25 Moon in last quarter, 2:41 a.m.

28 A thin sliver of waning crescent moon joins Saturn high in the east before twilight.

30 Sunrise, 6:31 a.m.; sunset, 6:18 p.m.

Clair Wood taught physics and chemistry for more than a decade at Eastern Maine Technical College in Bangor. Send astronomical queries to Clair Wood at cgmewood@aol.com or care of the Bangor Daily News, Style Desk, P.O. Box 1329, Bangor, Maine 04402.