Heads UP! for May 2013

[An expanded discussion will be in the Almanac column in the upcoming Westchester Astronomers newsletter for May.]

In May, you can stay up all night with Saturn! Not that you would, but it’s nice to know that Saturn, the ringed planet, is there for you. Saturn rises in the east as the Sun is setting. While Saturn is brighter than all but seven stars in our sky, it is not as obvious as outstandingly brilliant Jupiter, in the western sky at sunset. Follow Jupiter this month as it falls down into the twilight brightness, leading us to a three-planet-pile-up low in the west-northwest just after sunset this Memorial Day weekend. Don’t forget to spend some time looking for its brightest moons and the dark cloud bands on the planet.

I often say…..
“Binoculars will help you find [fill in the blank with a great astronomical sight!] low in the twilight sky”
….This time, take my advice over the Memorial Day weekend. About 40 to 45 minutes after sunset, look for the pile-up of bright planets low in the part of the sky just above where the Sun sets. Spying Venus, Jupiter and Mercury, all together in the wide view that binoculars provide, will be worth the need to find a clear western horizon so you can look low in the west northwest. Many popular space websites will show charts with directions.

Saturn is just past opposition, rising at sunset, getting higher in the evening sky this month. A good spotting scope or most telescopes will show the ring that makes Saturn different from the other bright lights in the sky. Saturn is still tiny, even in a telescope, but if you get a steady sky and increase the magnification, Saturn’s rings will show some details and the subtle cloud bands and moons will be visible. Saturn’s Titan is the second largest moon in the Solar System, smaller than the champion, Jupiter’s Ganymede. Titan should be visible in a telescope, and other moons in a larger telescope.

Strange two-faced moon Iapetus is visible to the south of Saturn around May 10th. It moves west of Saturn, brightening to magnitude +10, as it approaches greatest elongation on the 30th. Iapetus’ orbit is tilted compared to the rings, so future Iapetians will have a great view of Saturn’s rings for much of the moon’s 79-day trip around Saturn.

The Moon will have a weak penumbral eclipse near midnight on May 24/25. It will not be noticeable to our eyes. Even on the Moon, it would only be a partial eclipse of the Sun by the Earth, and only visible from the Moon’s South Pole. Of more significance, the Moon is closest to the Earth for May on the 25th, 21 hours after full Moon. The lining up of the Earth, Moon and Sun in a straight line, augmented by a closer than usual Moon, will make tides higher than normal. Also, an annular eclipse of the Sun – not a total eclipse – is not visible here, on the 10th at sunrise in Australia and later in the South Pacific Ocean. While we’re on the subject of things you can’t see, our best meteor shower in May peaks on the 5th. While you might see a few meteors at any time, almost all of the meteors from this shower are visible only south of 40 degrees north latitude.

The crescent Moon makes a nice photo op with Jupiter on the 11th and 12th. The Moon just misses Spica on the 22nd.

Twilight lasts longer as we get closer to the summer solstice on June 21st, more and more earth-orbiting satellites are visible each night, some as late as midnight. The International Space Station is not visible here for the first half of the month; after that, it is seen in the morning sky. In early June, the ISS is visible as often as five times a night, every 96 minutes.

Abrams Planetarium is offering a sky calendar and chart of bright stars in the sky for May at http://www.pa.msu.edu/abrams/. I love their great diagrams of where to find bright objects in the sky. For May, it’s free and you can make copies, this month only! Or you can download a copy, below….


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