Astronomy From Your Back Yard - 5/12 to 5/ 18 2010

Thursday, May 13 2010 @ 10:54 pm EDT

Contributed by: dgrosvold

By Dave Grosvold

If the weather is clear, backyard astronomers will have an opportunity to catch a glimpse of a New Moon just a few hours old this Friday evening, May 14th. Find a place with a clear western horizon with no obstructions, and grab a pair of binoculars.

Look to the west-northwest right after sunset (from about 8:00 PM to 8:30 PM) below Venus and you will see the very thinnest sliver of a waxing crescent Moon. Many intermediate and advanced amateur astronomers have competitions to see who can spot the youngest crescent Moon just after New Moon. This month, New Moon occurred at 8:05 PM CDT on Thursday, May 13th.

Any clear evening this week, look for Saturn and Mars on opposite sides of the constellation Leo in the south-southwestern sky. These two planets dominate the sky most of the spring and summer this year. You should be able to spot Saturnís moons in a larger pair of binoculars (10 x 70) or small telescope (3 inch or larger.)

If the weather is clear, The International Space Station (ISS) is also visible several times this week. The ISS makes magnitude -2.2 and brighter passes overhead every evening Friday through Monday. The table at the bottom of this article shows the times, altitudes, magnitudes, and directions of these passes. You can check for additional passes and times.

You should also able to spot several bright Iridium Flares this week. On Friday, May 14th at 10:30 PM CDT, Iridium 40 passes to the ENE (azimuth 70°) at an altitude of 33°, with a magnitude of -4. Astronomers refer to azimuth (Abbr: Az.) and altitude (Abbr: Alt.) instead of direction and height, but you can easily remember that azimuth is the same as the bearing on a compass, so az. 0° is North, Az. 90° is East, Az. 180° is South, and Az. 270° is West. When astronomers refer to altitude, Alt. 0° is at the horizon and Alt. 90° at the zenith (the zenith is the highest spot in the sky at any point in time, that is, directly overhead.) So that means Alt. 45° is halfway up the sky from the horizon to the zenith.

Saturday morning, May 15th at 4:08 AM CDT, Iridium 60 will pass to the ESE (Az. 111°,) at Alt. 17° above the horizon, but it will be bright, at magnitude -6. That same Saturday evening at 8:49 PM CDT, Iridium 54 passes high overhead in the E (Az. 97°) at Alt. 66°. Iridium 54 will be almost as bright as Iridium 60 at magnitude -5.

Monday morning, May 17th, at 4:05 AM CDT, Iridium 90 passes low in the ESE (Az. 114°) at Alt. 19°, magnitude -4. Then on Tuesday, May 18th, at 3:58 AM CDT, Iridium 59 makes a bright appearance low in the ESE (Az. 116°) at Alt. 16°, at a magnitude of -6. Several other dim Iridium Flares will occur during the week as well. Again, you can check the times and locations at

On the morning of May 16th, look for Jupiter and Uranus to rise together, within 3° of each other on the eastern horizon at 5:00 AM CDT. Uranus is hard to spot, and may only be visible in binoculars or a small telescope, depending on your location. They will continue to rise closer together until they get within 0.5° of each other in early June.

International Space Station Visibility — May 12 - May 18
TimeAlt.Az. TimeAlt.Az. TimeAlt.Az.
14 May -2.5 21:42:35 10° NW 21:45:25 41° NE 21:45:52 38° ENE
15 May -2.2 22:07:18 10° WNW 22:09:41 39° WSW 22:09:41 39° WSW
16 May -2.6 20:56:50 10° NW 20:59:40 44° NE 21:02:03 13° ESE
17 May -2.4 21:21:31 10° WNW 21:24:19 40° SW 21:25:58 20° SSE

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