JUNE  2006

JUNE STAR MAP | STARWATCH INDEX | MOON PHASE CALENDAR

Print Large Sky Charts For 10 p.m. EDT:   NORTH | EAST | SOUTH | WEST | ZENITH

 

Solar X-rays:   Geomagnetic Field:

Current Moon Phase

511    JUNE 4, 2006:   Mental About Mercury

If you are a frequent reader of this column, you have probably inferred that I am hooked on the planet Mercury. Second smallest of the official nine, Mercury has many similarities to Earth’s nearest neighbor in space, the moon. It is a rocky world with plenty of meteorite craters and evidence that the planet experienced titanic amounts of volcanic activity. It makes precisely two orbital loops around the sun for every three rotations, making a day on Mercury, from sunrise to sunrise, equal to 176 Earth days in length. Because of this spin-orbit coupling relationship, the same regions of the planet are always facing the sun when Mercury is closest or farthest from our daystar. It was on my birthday, June 10, thirteen years ago, that I had one of my most meaningful encounters with the Messenger God. Up until then, I had only seen Mercury through binoculars and only once in the eyepiece of a telescope. The evening was clear and cool, and I went to my favorite haunt in Coopersburg where I normally observe the planets when they are in the west. I found Mercury easily enough with optical aid, and then staring in the same direction, I lowered my binoculars. There it was. I held its image for about five seconds, then blinked, and lost it. What a great birthday gift, I reflected. Since that time I have had cataract surgery, including corrective lens implants, which has allowed me to see Mercury with the unaided eye on a regular basis. I even saw it through my front car window earlier this year. If the night is clear, the next three weeks will be nearly ideal for observing the most elusive of the naked eye planets. Point your eyes left of the sunset glow about 45 minutes after sundown on any clear evening. The star-like object near the horizon will be Mercury. Binoculars are still suggested.

Mercury returns to the evening sky for a debut which will last all through June. Mercury could be seen on Sunday, May 28 near the tree tops (center-right) along with a moon less than two days old. Canon D20 photography by Gary A. Becker...

512a  JUNE 11-13, 2006:   Mars Catches Saturn in the West

This is the week that Mars passes Saturn in the western sky during evening twilight. It is also the first of two really optimum weeks for viewing Mercury. Mars has been steadily approaching Saturn during the last several months, but over the past two weeks, it has become obvious just how fast their separations are narrowing. During the beginning of this week, search for Saturn with binoculars about 9:30 p.m. It will be almost due west about 20 degrees above the horizon. Through binoculars, Mars will be to the right and slightly below Saturn, about one half of a binocular field of view away. By Wednesday, Mars has closed to just over one degree, or two moon diameters from Saturn. More interestingly, Mars will be virtually in the middle of the Beehive star cluster in Cancer the Crab. By 10 p.m., the Earth’s rotation has carried Mars and Saturn to within 13 degrees of the horizon, but it should be easy to spot the stars of the Beehive surrounding Mars with binoculars. Even more spectacular will be viewing reddish Mars through a telescope. By Saturday, Mars and Saturn will appear only one moon diameter apart and be visible at moderate powers through telescopes. The Beehive cluster will be only one degree to the right, still close enough to be seen with wide field scopes at low magnifications. Also in line with Mars and Saturn, but below Saturn on Saturday, will be Delta Cancri, one of the principal stars of Cancer the Crab. It will still be over four times fainter than Mars. In all of the excitement, don’t forget about Mercury, which is in its best position for viewing during June. By 9:30 p.m., Mercury is still seven degrees or one binocular field of view above the horizon in the WNW. The Messenger God will be just a little fainter than Saturn.

From left to right, Saturn, Mars, Pollux, Castor, and below Castor, near the trees, Mercury... Canon D20 photography taken on June 10 by Gary A. Becker...

512b  JUNE 14-17, 2006:   Mars Catches Saturn in the West

This is the week that Mars passes Saturn in the western sky during evening twilight. It is also the first of two really optimum weeks for viewing Mercury. Mars has been steadily approaching Saturn during the last several months, but over the past few weeks, it has become obvious just how fast their separations are narrowing. Search for Saturn and Mars about 9:30 p.m., earlier with binoculars. They will be almost due west about 20 degrees above the horizon. At the beginning of this week, Mars and Saturn were separated by about one half of a binocular field of view. On Wednesday, Mars has closed to just over one degree or two moon diameters from Saturn. By 10 p.m., the Earth’s rotation has carried Mars and Saturn to within 13 degrees of the western horizon, but the planets will still be easy to spot under a clear sky with an unencumbered horizon. By Saturday, Mars and Saturn will appear only one moon diameter apart and be visible at moderate powers through telescopes. The Beehive cluster in Cancer the Crab will be just to the right, close enough to be seen with wide field scopes at low magnifications. Also in line with Mars and Saturn, but below Saturn on Saturday, will be Delta Cancri, one of the principal stars of Cancer. It will be over four times fainter than Mars. Don’t forget about Mercury this week either. It is in its highest position for viewing during mid-June. By 9:30 p.m., Mercury is still one binocular field of view above the horizon in the WNW. Under the very clear conditions that prevailed on June 10, Mercury was easy to follow right down to the tree line of my WNW Coopersburg horizon. See http://www.astronomy.org/ StarWatch/June/index-6-06.html for wide field pictures of Mercury, Mars, Saturn, and the moon.

From left to right, Saturn, Mars, Pollux, Castor, and below Pollux, near the trees, Mercury... Compare how much closer Mars is to Saturn from the June 10 image found above and how Mercury has moved from below Castor to below Pollux. The faint stars around Mars are part of the Beehive star cluster in Cancer the Crab. Mercury disappeared behind the tree line at 9:59 p.m. EDT. Canon D20 photography taken from Coopersburg, PA on June 15 by Gary A. Becker...

Notice the change in position of Mars and Mercury from June 15 (photo above this one) to June 16. Canon D20 photography by Gary A. Becker...

Very hazy conditions were prevalent on the evening of June 17 when Mars (fainter) and Saturn were nearest to each other. The star below Saturn is 4th magnitude Asellus Australis in Cancer the Crab. Mercury is visible, right of center, near the tree line. Canon D20 photography by Gary A. Becker...

513    JUNE 18, 2006:   It's Summertime

On Wednesday the sun reaches its farthest position north of the equator at 8:30 a.m. EDT. Somewhere in the desert of Africa’s northern Mauritania, the sun will be shining precisely overhead at local noon, defining its northern limit and the location of the Tropic of Cancer. It will be the inauguration of my favorite season, summer. The seasonal changes result from the tilt of the Earth’s axis which is tipped 23-1/2 degrees from the perpendicular to Earth’s orbital plane. A line which is perpendicular to another line simply intersects it at a 90 degree angle. I can see former students reading this article grimacing right now. It is no coincidence that the Tropic of Cancer is related to the Earth’s axial inclination. It is this tilt which defines where some of those strange dashed circles on a globe are positioned. The Tropic of Capricorn is located at 23-1/2 degrees south of the equator and is the southernmost limit where the sun can be directly overhead. In Fairbanks, Alaska, positioned at nearly 65 degrees north latitude, there will be a 24-hour celebration because here the sun will not set. Actually it does, but just barely. No one takes notice, however, because everyone in Fairbanks is just plain being too merry. Above 66-1/2 degrees north latitude, which incidentally is 23-1/2 degrees south of the North Pole, the sun remains visible for increasingly longer periods of time. Poor Santa has it the worst with six months of continuous sunshine. Old St. Nick has ceaseless work during the months leading up to Christmas and insomnia during the half year when the sun simply does not set. To add to his woes, global warming has made the North Pole accessible to tourists who book passage on Russian icebreakers. Oy vey! Not only is the Christ being taken out of Christmas but the Merry too!

514    JUNE 25, 2006:   On the Horizon

I am happy to announce that corn has been growing on the plot of land that I look across while viewing the western sky at dusk. I have heard a rumor that it’s owned by DeSales University, so maybe it will be spared the contractor’s bulldozer for many years into the future. On the East Coast, finding open space with good horizons is becoming more of a challenge, but it is this area of the sky that intrigues me the most. Here, humans made their first successful attempts to harness the motions of the cosmos, to create calendars, so that the precise rhythms of nature could be monitored against the vagaries of the weather. It is also along the horizon, especially during the intervals of evening twilight and morning dawn, that the sky is for me the most beautiful. Esthetics, not only in the predictive, mathematical sense, but also in the sheer beauty of the night continues to influence why I enjoy this science so much. About an hour after sunset is the sweet time for viewing. Tuesday finds a fingernail sliver of a moon just to the right of Saturn. Equally distant, but below the moon, will be Mercury. Mars will be above and to Saturn’s left. Use binoculars this week to enhance the moon’s ashen light, reflected sunlight from a gibbous Earth sent back to us by the moon. Wednesday finds Mars just below the waxing crescent moon. Thursday, the moon is just to the right of Regulus, the brightest star in Leo, the Lion. In the morning twilight, watch for yellow-white Venus low in the ENE about 4:30 a.m. To Venus’s left, a little higher in altitude, is the sixth brightest star of the night, Capella. Above Venus will be the Pleiades, or Seven Sisters already heralding the cooler weather of the autumn months. Use binoculars to spot their small, dipper-like shape.