Have a Merry Saturnalia

Like ancient cities, one celebration is often built atop another

A couple thousand years ago, Romans gathered around December 25 to wish one another a Merry Saturnalia, the most popular holiday of the Roman year. Saturnalia was both a time to honor the god of agriculture, Saturn, and also a grand festival lasting up to seven days. There were feasts and celebrations, visits to friends and gifts to exchange. Religious historians believe that early Christians chose this day to mark the birth of Jesus so as to blend in with the Roman celebrations and escape detection and persecution.

The first-quarter moon appears high in the south at sunset Christmas Eve, around 4:50, and sets in the west a little after midnight. As the gibbous moon waxes through the week, it sets more than an hour later each night, until at full moon on the 31st it rises as the sun sets and sets with sunrise. The second full moon of December, this is commonly called a Blue Moon, although the term technically applies not to the second full moon in any given month but to the fourth full moon in a three-month season.

Mercury appears low in the southwest in the wake of the setting sun at 4:50. This fleet planet never strays far from the sun’s blinding light, climbing at best 15 degrees above the horizon. You may want binoculars to help locate this surprisingly bright light.

Sunset reveals brilliant Jupiter high in the southwest. Aside from the moon, there is no brighter light in the sky until the gaseous giant sets a little before 9pm. As Jupiter sinks beneath the southwest horizon, ruddy Mars rises above the northeast horizon. While not the brightest light in the heavens, Mars outshines all his neighbors, including first-magnitude Regulus, which follows on his heels by about 10 degrees. Saturn rises due east around midnight, trailing far behind brighter Mars, and remaining visible until sunrise around 7:20.