June 2003

By Steve Stefanik

Astronomically summer begins on June 21^st at 3:10 p.m. EST. The sun rises the farthest north on the eastern horizon, is at its highest point in the sky (70.5 degrees at our latitude) at noon, and sets the farthest north on the western horizon on the day of the solstice.

The planets Mercury and Venus also happen to be within half a degree of each other in the constellation Taurus the bull the same day low on the northeastern horizon about half an hour before sunrise. Venus is unmistakable at –3.9 magnitude but you may need binoculars to spot Mercury. Venus remains the "morning star" throughout the month but Mercury falls from view after this conjunction.

The "naked eye" planets of Jupiter and Saturn will still be visible this month. Jupiter, at –1.9 magnitude, still dominates the western sky at nightfall and is the brightest object in and around the constellations Cancer the crab and Leo the lion. Saturn is lower than Jupiter above the northwestern in the constellation Gemini and considerably dimmer in magnitude at +0.1. Saturn sets by the end of the month and rises in the east in the early morning twilight next month.

Mars is the planet to start watching as summer begins. It rises above the eastern horizon around 1:00 a.m. at the beginning of the month and by midnight at the end of the month. Look for the rusty red –0.7 magnitude disk between the constellations Capricorn the sea goat and Aquarius the water bearer. It will brighten rapidly in the upcoming weeks and grow rapidly in size. By June 21^st its apparent diameter will have already surpassed all of the oppositions of the 1990’s. It is expected to reach 25 arc seconds in angular diameter when it reaches opposition the last week of August when it will be closer to Earth than it has been in the past 50,000 years.

The planets Uranus and Neptune are also visible in the same part of the sky as Mars but you’ll need binoculars or a telescope to spot them because Uranus is only +5.8 magnitude and Neptune is even dimmer at +7.9. Mars passes 2 degrees south of Neptune on the 13^th and 3 degrees south of Uranus on the 20^th.

If you have the patience and a telescope with at least an 8-inch aperture you may be able to spot the +13.8 magnitude planet Pluto among the stars of the constellation Ophiuchus "the big oaf" when it reaches opposition on the 9^th. The only way to tell if it’s Pluto is to observe its movement in relation to nearby background stars after a lengthy period of time. The good news is that you have plenty of time to observe whether it moves or not because it will be visible all night long.