SkyWatch
June 2000
by Steve Stefanik
The parade of planets which have adorned the night-time sky throughout winter and early spring is over. Mars is lost in the glow of sunset on the western horizon. Jupiter and Saturn don’t rise until a half hour before sunrise in the east leaving the lone planet Mercury hovering above the western horizon as night falls. The good news is that this month will provide the best appearance of this elusive planet this year.
During the first 10 days of June, Mercury will be at its highest point, 18 degrees above the west-northwestern horizon. Try locating the +0.6 magnitude planet by scanning the horizon right where the sun sets because Mercury is the closest planet to the sun and doesn’t stray very far from it. Be careful not to look at the sun through binoculars! Serious damage could occur to your eyes.
Mercury reaches greatest elongation on June 9th when it will be more than 24 degrees from the sun. By the 16th, it will still be 23 degrees from the sun but will disappear from view.
As you scan the western horizon in search of Mercury you may notice how far north the sun is now setting. This northerly advance of the setting sun, called the Summer Solstice (the sun stops advancing), will cease on the 20th of June at 9:38 p.m. EDT. Although this is the day with the longest number of daylight hours (15 hours) it is not the day when the sun sets the latest. That will occur a week later on the 27th.
If you want to observe any of the other planets that are visible you’ll have to turn your attention and your alarm clock to the early morning hours before the sun rises in the east. The planets Jupiter and Saturn which were in close conjunction (1.2 degree) in the month of May are still in close proximity. By June 13th they are 2 degrees apart and by the 24th only 3 degrees apart.
The planets Uranus and Neptune rise around mid-night in early June and mid-evening by the end of the month but they may not clear the treetops by the time you go to bed. The best time to view them is when they are high in the southern sky but that won’t occur until the early hours of the morning after mid-night. You’ll need powerful binoculars or a telescope to spot them or simply wait until the month of August when they will be well placed in the southern sky in the early evening and much brighter when they reach opposition directly opposite the sun.