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A Guide to the Night Sky: February 2017 - Tre Gibbs LLAS


A Guide to the Night Sky
February 2017 

By Tre Gibbs, LAAS

The longest nights of the season are behind us. Before you know it we’ll be setting our clocks ahead one hour in preparation for Spring. But we are still in Winter’s grip and will be for at least another four weeks, although there are signs everywhere that winter will soon be departing. One of those signs is the night sky.

Before there were calendars, ancient people used the night sky to gather all kinds of information vital to their survival. Our ancestors also knew that living in a rhythmic, seasonal harmony with our planet gave them the best shot at longevity and continued propagation.

One major component of the night sky is the annual parade of stars and constellations. As Earth continues it’s yearly orbit around the sun, at night we see different patterns of stars at different times of the year. This is how our ancestors knew not only what time of year it was, but perhaps more importantly, what time of year was coming. This information enabled them to prepare for the coming rains, the winter’s cold, the planting, growing and harvesting seasons, all of which were necessary for survival.

Our ancestors also used the moon to measure time. Like the sun and stars, the moon also has a consistent cycle. Roughly every 28 days or so the moon completes one orbit around Earth, marking one month. FUN FACT: our word “month” comes from “moon”.

It’s a little more difficult to keep track of the planets. Even though they too follow the same path in the sky as the sun and moon, their movement can seem quite random and erratic, since each one is traveling in it’s own separate orbit, at it’s own different speed.  Mars and Venus, Earth’s two neighboring planets, are visible early in the evening, just after twilight high in the southwest. While Venus is obvious - the brightest star-like object in the sky - Mars has diminished to the point where it looks just like another small star with a hint of color to it. But don’t fret, the moon is also a cosmic guide and will help you find Mars! On the evening of February 1st, look to the SW after sunset to find a young crescent moon above the tiny but pinkish Mars, which is just above and to the left of the brilliantly glowing Venus. The three objects will appear to be in a straight line, with almost equal space between them. But the moon doesn’t hang out for very long. By the following night, February 2nd, the moon will have drifted eastward, away from the planetary duo, continuing it’s own monthly orbit around Earth. In fact, the next time the moon comes around to visit Mars and Venus will be on the nights of February 28th and March 1st - one “moonth” or month later.  

But what about Jupiter?  Jupiter, the 4th brightest object in the sky after the Sun, Moon and Venus, returns to our evening skies this month!  Rising in the east around 11:30 pm in early February, by month’s end the Roman “King of the Gods” will rise almost two hours earlier, at 9:30 pm.

More on Jupiter (and Saturn) next month… until then stay warm, stay dry and KEEP LOOKING UP!