The Moon Occults Venus

September 10, 2013

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Photographer: Sebastian Guillermaz; Sebastian's Web site
Summary Authors: Sebastian Guillermaz; Jim Foster

The photo above shows the crescent Moon in the process of occulting Venus as observed from Chascomus, Argentina, on September 8, 2013. Spica is to the lower left of the waxing, crescent (12 percent illuminated) Moon. This impressive sight was only visible from the region of the globe around southern South America, just before and just after sunset on the 8th.

It might seem that our big, old Moon would routinely pass in front of stars and planets. However, in spite of the fact that the Moon is basically in the same plane (plane of ecliptic) as the planets, such occultations come about infrequently -- the Moon occults Venus just once in 2013. The Moon will only occult stars with an ecliptic latitude of less than about 6.5 degrees. Only first order magnitude stars Regulus, Spica, Aldebaran and Antares can be occulted in the current epoch. Note the ashen earthshine on the non-illuminated portion of the Moon.

Photo details: Camera Model: Canon EOS 7D; Lens: EF70-200mm f/4L USM; Focal Length: 200mm; Aperture: f/8.0; Exposure Time: 0.250 s (1/4); ISO equiv: 800; Software: Adobe Photoshop CS6 (Windows).