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The Occultation of Venus

September 11, 2013  •  Leave a Comment

Occultation Sequence On September 8th 2013 the Moon occulted Venus for part of South America. After having missed the Venus transit in 2012 I thought it was a good compensation to live exactly in the area of the world where this occultation was visible. This "Syzygy" is one of the most visible occultations you can witness as it features the two brightest natural objects in the night sky.

The map shows the visibility of the occultation.

Sun, Moon and Venus The first photo shows the Sun still above the horizon looking carefully you will notice the Moon above and just above the Moon Venus. The photo, in some way, shows how Venus is actually easy to see at daytime if you know exactly where to look. A reference like the Moon is perfect, I could see both the Moon and Venus without any problems about one hour before sunset. I believe the same would have been possible at noon without much difference.

Moon and Venus before the occultation Once the Sun was below the horizon both the Moon and Venus became apparently brighter as there was more contrast between them and the sky. Venus was at magnitude -4.1 at this time so it was really bright next to the 3 days old waxing crescent Moon. There were some clouds but the conditions looked good for the occultation. 

Occultation at Dusk At about 6:50 pm Venus touched the Moon's dark limb and the occultation started. Visually the planet just disappeared from sight as it had just vanished in the sky. Dark limb occultations are quite magical, you don't see the occulting body so the eclipsed one just disappears from the sky in a few seconds.

The ISS visits the occultation While Venus was still behind the Moon the International Space Station made a pass crossing just next to the Moon. It was a very night sight. 

Half a Venus At 7:50pm almost exactly after one hour of the start Venus reappeared from behind the Moon's bright limb. I could take some photos of "half a Venus" as the planet was half occulted and half visible. 

Occultation and Earthshine As the planet got sepparation from the Moon I took a longer exposure to show Earthshine, the illumination that our own planet casts on the Moon's disc.

Emerging sequence The planet quickly got separation from the Moon. As the separation got larger Venus looked brighter. 

This occultation was a beautiful show, the Moon was in a very nice phase for photography and visual observing, it was quite high in the sky and the weather cooperated for the whole event. The next occultation from my location will be in January 2015, when the Moon occults Saturn,I'm sure it will be like this one only completely different!





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