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Monday, July 30, 2012

Jupiter's Disappearing Act

One of the most beautiful celestial events I have seen in a long time occurred early on the morning of Sunday July 15th, and Israel was perfectly placed for it. The waning crescent moon occulted Jupiter and its four Galilean satellites over the skies of Mitzpe Ramon. An occultation occurs when one astronomical body passes in front of another and blocks its light for a period of time. In this case the moon, at about 230,000 miles distant from earth that morning passed in front of Jupiter and its moons, about 526,963,352 miles distant, a ratio of 2,291 in distance! The moon approached Jupiter, slowly engulfed two Jovian satellites to its right, then the planet, then the two remaining Jovian satellites, and reversed the process about an hour later. The moon and Jupiter were in a very rich area of the sky that night, in the constellation Taurus with the Hyades star cluster nearby, along with the bright, red star Aldebaran and many other stars nearby that were only visible in the telescope.

Because such events are so beautiful and memorable, I had called for a star party to begin at 3:00AM that morning. Despite the early hour, about 30 people showed up, some from as far away as Gush-et-Zion, along with many from Mitzpe Ramon. I had set out 4 telescopes and a pair of giant binoculars, so we were well provisioned for the night. The weather was warm, the sky clear, and the desert winds that blow most of the night had quit for the evening, as the temperature in Machtesh Ramon and on the rim, where we were, came into equilibrium.

The first photo shows the rich star field that the moon was entering as it began to engulf Jupiter. Jupiter is hidden in the overexposed glow of the moon which was necessary to show some of the dimmer stars.

The rich star field around Jupiter shows the Hyades star cluster below and to the right of Jupiter with the brilliant red supergiant star Aldeberan directly below the moon. Many other stars are shown in the field and must have also been occulted by the moon, but little mention was made of them in pre-occultation summaries of the event. Jupiter is hidden in the moon's glare near the bright limb. Photo: Ira Machefsky
Jupiter and its four Galilean moons about to be occulted by the moon, along with other bright stars in the vicinity. In order from the very left: Callisto, Ganymede, Jupiter, Io, Europa, Moon. Photo: Roy Brown
Jupiter about to be occulted by the moon. Photo: Roy Brown
Jupiter, preceded by Io and Europa, emerges from behind the moon. Photo: Roy Brown
Jupiter and all four of the Galilean moons emerge about an hour later. Another star, identity unknown, to the left of the moon is just a few minutes away from being occulted. Photo: Roy Brown
As the moon moved away from Jupiter and its moons, the tableau took on the appearance of some vicious primitive weapon, the scythed blade of the moon being held by the spindle of Jupiter and its moons.

The vision was made all the lovelier by the appearance of Venus on the scene, just before sunrise. Venus was shining near its maximum magnitude of -4.7, a beacon below Jupiter and the moon in the gathering light of day.

Venus rises brightly below the crescent moon and the exiting Jupiter as Aldeberan shines above and to the right of the Morning Star. Photo: Ira Machefsky
Finally, a scene that few got to see: Sunrise at our observing location, the rim of the world's largest erosion crater, Machtesh Ramon:

Sunrise on Machtesh Ramon, after the Jupiter occultation. Photo: Ira Machefsky

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1 comment:

  1. The boys and I had a great time. Thanks Ira, for a great evening.

    See my pics here:

    (Gush Etzion)



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