With winter’s late-rising sun we’ve been treated to so many beautiful sunrises these past weeks. It’s been too easy to get out of bed around 7:30 and just look out the window. Even before rising, the coming sun reddens the underbellies of any clouds present or fashions a feather of light from minute ice crystals suspended in the atmosphere.
These same circumstances let us take advantage of the morning crescent moon, sometimes called the “old moon.” It’s old because it’s nearing the end of an orbital cycle that began about four weeks ago with the “new moon.” The next new moon occurs on Christmas night, so we’ll see an extremely thin crescent just one and two days before new the next two mornings. Call it old if you like, but the sight will rekindle that sense of wonder you’ve carried inside since childhood .
The best viewing time is between 90 and 45 minutes before sunrise on Dec. 23 and between one hour and 30 minutes before sunup on Christmas Eve. Click here to find your local sunrise time. If you’re out toward the darker end of that time frame you’ll glimpse the planet Mars and Antares, the brightest star in Scorpius. Both have a distinctly orange-red hue for different reasons — Mars from oxidized iron (rust) and Antares because it’s surface temperature is only 6,500° F (3,600° C), almost twice as cool as the sun. Cooler stars glow redder, hotter ones, blue-white.
2020 will be a superb one for the Red Planet with a close approach to Earth on October 13 that’s guaranteed to get your attention. Between now and then the moon will cycle more than 9 times around the Earth, providing oodles of crescents. This week they’re early Christmas presents.