Saturday, May 19, 2012

Venus and the Pleiades

Venus is soon to pass through inferior conjunction and transit across the Sun's face on June 5, but before that it has been shining brightly in the western sky after sunset. This spring however the planet made a close approach to the star cluster M-45, also known as the Seven Sisters or the Pleiades. Venus was a fat crescent with the usual yellow-white featureless appearance, passing closest to the star Merope. Normally I look at the Pleiades from a dark location to see the reflection nebulosity that surrounds the entire star cluster, especially Merope whose nebulosity is also designated as NGC-1435.

This time the close passage of Venus to the star cluster made the effort to set up a telescope worthwhile despite the poor seeing and transparency that night. Within 20 minutes after sunset the star cluster was visible through my telescope and I had enough time to sketch out the brighter stars before the sky became too milky to continue farther. Using a 24mm Explore Scientific eyepiece with a huge 82 degree field of view gave an actual field of view nearly 1.5 degrees across, enough to get both objects in the field of view with space to spare. It was a wonderful sight that did not require a trip to a dark site to appreciate. Venus is about to encounter the Pleiades repeatedly in the coming years, with upcoming encounters featuring the planet passing between the seven bright main stars, a sight well worth looking for with a small telescope or even binoculars.

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