occultation – A Darker View

The Moon and Saturn

There will be a close approach of the Moon and Saturn tonight and tomorrow. At sunset on the 9th the pair will be separated by less than 7° and found well up in the eastern sky. As the night progresses the pair will slowly close the gap. As the pair sets around 03:30 the morning of the 10th, the separation will have been reduced to about 4°. As the two rise on the evening of the 10th they will have passed and the separation will be increasing. At sunset the pair will be 7° apart.

Viewers on the other side of our planet will be able to observe the closest approach, much less than a degree for many, an occultation if you happen to be in the right place. Sky watchers in Capetown, South Africa will see the planet disappear behind the limb of the Moon for about an hour around 19:11UT.

The Moon and Jupiter

This evening sky-watchers will note Jupiter directly beside a bright Moon. The pair will be very close separated by only 1°09′ as of sunset here in Hawai’i. Accounting for the radius of the Moon this will mean that the planet will be only 55′ off the limb of the Moon.

Observers further east and south will be able to see an occultation, with the Moon passing in front of Jupiter. Here in Hawai’i the occultation will be over before sunset. It is no use observing during the daytime either, as the planet will pass north of the Moon for our latitude.

The proximity of the two does provide a nice opportunity to see Jupiter in the daytime, as the Moon will provide a signpost to the location of the planet. The pair will rise about 14:00HST and be well up before sunset. Look just to the north of the Moon (left as they rise) for a pinpoint of light. At -2.6 magnitude the planet should be easy to spot as long as the sky is clear and not hazy.

Elongations, Conjunctions and Oppositions

As a planet moves across the sky there are particular points in its orbit that describe the motion, part of the jargon of astronomy that can confuse the uninitiated. These terms do not represent anything difficult, you just have to visualize what they mean. Understanding the movements of planets across the sky gives a little insight into our beautiful universe.

Elongation, opposition and conjunctions, the apparent positions of a planet with respect to the Earth

The terms used commonly here on Darker View are ideas that date back to the early beginnings of astronomy. Those ancient astronomers were fascinated by the movements of the bright wandering stars, the planets. They tracked and recorded the motions meticulously and invented the terminology we still use today to describe those motions.

Superior Conjunction, Inferior Conjunction, Opposition and Maximum Elongation tell any experienced skywatcher exactly where a planet is with respect to the Earth, where it is in our sky, and where it will be in the coming weeks or months. It is all part of the intricate patterns of our solar system that allow anyone who learns to become familiar with the night sky.

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