Mercury, Venus & Jupiter Congregate in the West

Look low in the west after sunset in late May to catch Venus, Jupiter, and Mercury dancing closely in the sky. The best time to see them should be 40 minutes after local sunset. See the video prepared by Sky & Telescope for the planets positions relative to each other over several weeks into June. From Friday, May 24th through Wednesday, May 29th Venus, Jupiter, and Mercury will all be within 5 degrees of each other providing a great opportunity to check them out in binoculars. You should be able to see all three planets in the field of view in your binoculars. Brilliant Venus will be the brightest followed by Jupiter and Mercury. This celestial sky show will take place on the western skyline about 10 degrees (the height of your clinched fist held at arm’s length) above the horizon. Jupiter falls from view beginning on June 6th while the Moon begins to make it’s presence known very low on the horizon on June 9th.

Video courtesy of Sky & Telescope.com

A Penumbral Grazing on May 25th

Lunar eclipse chart for May 25, 2013
Lunar eclipse chart for May 25, 2013

The May 25th penumbral lunar eclipse will be practically imperceptible for creatures viewing from Earth. Most folks won’t even bother to try to see this eclipse and hardcore amateurs with telescopes will probably scoff at the idea of unpacking and setting up their telescopes for this event. That still doesn’t change the fact that however slight the moon’s grazing of the Earth’s penumbral shadow, and this one is about as scant as they get, it still technically counts as an eclipse.

So why is this such a non-event? Well there are three parts that make up a bodies shadow. The penumbra, the umbra and the antumbra. The penumbra is the weak or pale part of an object’s shadow, in this case the Earth’s shadow. From within the penumbra, the Moon is only slightly cast in shadow as in the case of a partial eclipse. This contrasts with the umbra, where the Moon is completely within the Earth’s shadow which sometimes results in a total eclipse. If it’s a total solar eclipse then the Moon’s shadow is cast on the Earth. On the other hand if it’s a total lunar eclipse the Moon passes through the Earth’s shadow, and more specifically, the Earth’s umbra. You can think of the umbra as a cone getting smaller as it retreats from an object. The antumbra is that portion of the shadow past where the umbra’s cone of influence ceases. If you’ve seen an annular eclipse you’ve witnessed the antumbra first hand.

So what we have on May 25th is the Moon ever so slightly creeping into the Earth’s penumbra. The partial eclipse begins at 10:53 p.m. CDT and lasts 33 minutes and 45 seconds, the big non-event will be visible (or not) for all in North America.

Sky-Watchers’ Guide: Solar Eclipse Thursday

Sky-Watchers’ Guide: Solar Eclipse Thursday.

A “ring of fire” solar eclipse will darken skies on Thursday as the black silhouette of the moon will appear to glide across the face of the sun until only a bit of sunlight is visible. (See annular eclipse pictures.)

Though the celestial phenomenon will be visible mostly in remote areas in the Pacific, armchair astronomers can watch a live feed of the eclipse, thanks toSLOOH.

The Internet-based space-tracking service is broadcasting the annular eclipse via a telescope from Australia starting on May 9 at 4:30 p.m. CDT (21:30 UT).

New Moon

Lunar Phases
Lunar Phases

New Moon occurs this Thursday evening May 9, 2013 at 6:31:40 p.m. CDT. The phrase new moon means the lunar phase that occurs when the Moon, in its monthly orbital motion around Earth, lies between Earth and the Sun, and is therefore in conjunction with the Sun as seen from Earth. More precisely, it is the instant when the Moon and the Sun have the same ecliptical longitude.

The Moon takes 27.3 days to orbit Earth, but the lunar phase cycle (from new Moon to new Moon) is 29.5 days. The Moon spends the extra 2.2 days “catching up” because Earth travels about 45 million miles around the Sun during the time the Moon completes one orbit around Earth.

Why do we always see the same side of the Moon? Only one side of the Moon is visible from Earth because the Moon rotates about its axis at the same rate that the Moon orbits the Earth. This is known as synchronous rotation or tidal locking.

The Moon’s diameter is 2,159 miles. This is about 3.7 times smaller than the Earth, making it the Solar System’s fifth largest moon, both by diameter and mass, ranking behind Ganymede, Titan, Callisto, and Io.

Comet C/2012 F6 Lemmon in May

Comet Lemmon in May
Comet Lemmon in May

In late April Comet Lemmon crossed the celestial equator making its way north. Good news for us! If you missed Comet PANSTARRS in March you can search for Comet Lemmon low in the morning sky, just above the eastern horizon. You’ll need binoculars or a small telescope to spot Comet Lemmon. Begin by sweeping slowly with binoculars about one hour before sunrise, looking for a fuzzy “star” with a short tail. The comet will be fading as the days of May tick away so observe early. Tomorrow morning (May 6th) a thin crescent Moon will pass a short distance south of Comet Lemmon making it a little easier to find. Comet Lemmon, which was discovered in March 2012, is traveling alongside the Great Square in Pegasus and will continue to do so the next few weeks (see finder chart). The chart shows the sky facing east at 5:30 a.m. on the days indicated.

 

2013 Eta Aquarid Meteor Shower

The 2013 Eta Aquarid meteor shower peaks tomorrow morning, Sunday May 5th. The best time to view the sky is that couple of hours prior to dawn. The Eta Aquarids can produce up to 20 to 40 meteors per hour. This shower favors the southern hemisphere slightly but on a good year from the southern portion of the U.S. you might see about 10 to 15 meteors per hour.

This year is predicted to be a good year as the moonlight from the waning crescent moon shouldn’t cause to much trouble. The Eta Aquarid meteors are swift-moving and seasoned sky watchers know to look for persistent trains from the brighter ones.

The graphic above shows the sky looking east at 5 a.m. on Sunday May 5, 2013. The red Telrad bulls-eye is the Eta Aquarid shower’s radiant  The radiant is that point in the sky where the meteors appear to originate from but you do not have to look only at the radiant to see the meteors. In fact, looking in that general direction if the sky a better choice.

How to bag the most meteors? I recommend finding a dark sky, a friend, don’t forget the coffee, a couple of lawn chairs that will allow you to lay back and take in as much sky as possible and enjoy the celestial show. Happy hunting!

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