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Friday, April 24, 2009

Mercury Setting: Conjunction of Mercury, the Pleiades, and the Moon April 26, 2009

NOTE: Aaaargh. I typoed "Pleiades" in the title. I fixed it, since it doesn't change the URL.

Mercury is in the final act of a month-long show that I have completely failed to mention until now. While it is several weeks past its brightest appearance, it will be giving a special performance this Sunday, April 26th, as it is joined low in the Western sky by a slim crescent Moon and the Pleiades, in an event best visible around 9:00 PM your local time.

Jack Horkheimer, Star Gazer: "Mercury At Its Best For 2009 Joined By The Moon And The Seven Sisters - Plus Celebrate National Astronomy Day On Saturday May 2nd!"

Astronomy.com - See Mercury, the Moon, and the Pleiades together in the night sky

Here is an illustration (stolen from the Astronomy.com article) of the event as it will appear on April 26, 2009:


I decided to try my luck Thursday night at imaging Mercury without the Moon to serve as a convenient guide. I had a general idea of where it would be in the sky, but wasn't sure which of the tiny little lights that I was seeing in the twilit sky was actually Mercury. After a while of receiving odd looks from passers-by, I went back inside to wait for the sky to darken a bit.

Even at 9:00 the sky was not dark enough for me to clearly distinguish what I was seeing. So I did the same thing I did when searching for Comet Lulin a while back: pointed the camera in a general direction, opened the shutter, and hoped for the best.


Here is the image that resulted. I have increased the contrast to bring out the stars more clearly. Two features are fairly easy to see here, at least in the larger image you can get by right-clicking on the picture and opening it in a new window or tab. The first is the partially-obscured constellation Orion dominating the left half of the sky.

Orion the Hunter. Note bright Betelgeuse at the top, the triangular
grouping of stars forming Orion's head at the upper right, the three stars of
Orion's belt in the middle, and the three stars - well, star, nebula, and star -
that form the sword in the lower left.

The other is the V-shaped asterism called the Hyades, which forms the head of Taurus the Bull*, on the lower right just above the closest rooftop.

The Hyades, the face of Taurus. Aldebaran glows red at the top left
of the V, marking the position of the bull's eye. Mars's path through the
sky occasionally places it in the Hyades near Aldebaran, giving the appearance of
Taurus having two red eyes. This is considered an astrologically
auspicious time to start wars. The first Gulf War was launched while Mars
was in the Hyades. Perhaps Ronald Reagan left a few of his Court
Astrologers around the White House to advise his former Vice President.

Unfortunately, overlaying a star chart (from Heavens-Above.com) revealed that I was somewhat off the mark here. Mercury, indicated by the blue circle on the far left of the chart, was lurking somewhere behind the house, as were the Pleiades. At least I have a better idea of where to look next time!


If you can, and if you have clear skies on the night of Sunday, April 26th, please try to see this beautiful conjunction. Let me know if you do!

*Fun fact: Taurus is actually only the front end of a bull, apparently charging out of the dome of the sky!

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