****************************************************** Abrams Planetarium SKYWATCHER'S DIARY June 1996 ****************************************************** The Skywatcher's Diary for June 1996 has been prepared by Robert C. Victor. Credit to Abrams Planetarium, Department of Physics and Astronomy at Michigan State University, together with mention of our Sky Calendar, would be appreciated. A sample Sky Calendar for May 1996 is available over the Internet. It can be viewed via a World-Wide Web browser such at Netscape or Mosiac, directly at URL: http://www.pa.msu.edu/abrams/may96skycal.html If you would like a printed sample, send a long, self-addressed stamped envelope to: June Sky Calendar Abrams Planetarium Michigan State University East Lansing, MI 48824 Each month, the Department of Physics and Astronomy at Michigan State University also makes Skywatcher's Diary available over the Internet. It can be accessed via a World-Wide Web browser such as Netscape or Mosiac, directly at URL: http://www.pa.msu.edu/abrams/diary.html The Skywatcher's Diary is also available via anonymous ftp at: www.pa.msu.edu in the directory /pub/swd ******* Lunar and Planetary Highlights for June ******* Venus in early June concludes its reign as evening star. On June 1 Venus is 13 degrees to upper left of setting Sun and follows Sun below horizon by just over an hour. On what date will you first see Venus as a morning star? Venus' rising in ENE precedes sunrise by half an hour on June 17, by 1-1/2 hours on June 30, and by over 3 hours on July 31. Venus' elongation, or angular distance to upper right of the rising Sun, widens from less than 11 degrees on June 17, to 27 degrees on June 30, and to 44 degrees on July 31. Look for Venus mornings about 3/4 hour before sunup and watch it get higher until early September. Since Venus swings so close to Earth early in June, its backlighted disk shows an unusually large crescent, still 0.8' (arcminute) across on July 1. That's big enough to discern its shape with 7-power binoculars, provided you observe Venus in a bright sky, around sunrise or even in daylight. By early July, once Venus has pulled far enough away from the Sun, it's easy to see it in the daytime -- just keep track of it until sunrise! The sunlit fraction of Venus' disk grows from 4% on June 21 to nearly 12% on June 30, and to 38% by the end of July. The Moon helps locate bright Jupiter on the nights of June 3 and 30. Between those dates, Jupiter's rising in SE shifts earlier, from 2-1/4 hours after sunset on June 3, to just a few minutes after on June 30. The Full Moon of June 30 is the second this month, an event not happening again until Jan. '99. A fat waning crescent Moon leads the eye toward Saturn in ESE predawn skies on June 9 and 10. Saturn's rings are then tipped 5.8 degrees from edge-on. Mercury passes 1.6 degrees upper left of emerging Venus on June 23. ********* SKYWATCHER'S DIARY: JUNE 1996 ******** Saturday, June 1 At sunset tonight, as soon as Sun's disk has sunk below horizon, locate Venus 13 degrees upper left of Sun and use binoculars to resolve the planet as a thin crescent, less than 3 percent illuminated. By half an hour after sunset, Venus is easy for naked eye even though it's just 5 degrees up in WNW. By an hour after sunset Venus has nearly set. The Strawberry, Rose, or Flower Moon -- first of two Full Moons this month -- is then low in SE with Antares, heart of Scorpius, 10 degrees to its lower right. Here's where to look for other planets during this first night of June. Three hours after sunset, look for bright Jupiter very low in SE, 30 degrees to Moon's lower left. For rest of night Jupiter follows Moon across sky. An hour before sunup on Sunday, Moon is low in SW and Jupiter is in SSW, to Moon's upper left. Saturn shines as a lonely first-magnitude "star" in ESE. In the next 15-20 minutes, use binoculars to scan ENE horizon for the rising of two more planets: First Mars, then Mercury 4 degrees to its lower right. This pair wll be easiest to see from southern states, and lost in bright twilight from N states. Sunday, June 2 At sunset, as soon as the Sun's disk has slipped below the horizon, use binoculars to search for the very thin 2 percent crescent Venus within 12 degrees upper left of Sun. Do not look at the Sun through binoculars! By an hour after sunset, Venus is gone and the Moon is rising in ESE. Wait another two hours, and you'll see bright Jupiter 15 degrees to Moon's lower left. Monday, June 3 Three hours after sunset, the waning gibbous Moon is very low in ESE to SE, with Jupiter just 4 degrees to its lower right. Moon and Jupiter keep company for the rest of the night, remaining 4 or 5 degrees apart until dawn on Tuesday, when they're in SSW. Tuesday, June 4 Three hours after sunset, Moon has just risen in ESE.Bright Jupiter is 16 degrees to Moon's upper right. Wednesday, June 5 Moments after the Sun has set below the horizon, use binoculars to look for the crescent Venus just 7 degrees to Sun's upper left. Tonight Venus' crescent is less than 1 percent illuminated. Do *not* look at the Sun itself through binoculars. Tonight might be your last evening to see Venus until April or May 1997. Venus now sets only half an hour after Sun. Thursday, June 6 A few leftover winter stars can still be seen in W to NW at dusk. Within an hour after sunset, find Pollux and Castor, the Gemini Twins, 4-1/2 degrees apart in WNW. Pollux is the brighter, on the left. Can you still see Procyon nearly due west just a few degrees above the horizon? Also, look for Capella in NW, 30 degrees lower right of Castor. Friday, June 7 On Saturday an hour before sunrise, the Last Quarter Moon is in SE; Saturn is within 20 degrees to its lower left. Face the Moon at sunrise, and you'll notice its left half is illuminated while the Sun is rising to your left. Sun and Moon are 90 degrees or one-quarter circle apart. Try to follow the Moon until midday. Saturday, June 8 On Sunday an hour before sunup face ESE to see the fat waning crescent Moon with Saturn about 6 degrees lower left. If you have an unobstructed view toward ENE horizon, aim binoculars there and try for the Pleiades star cluster with Mars 5 degrees to its lower right. Another 4 degrees lower right of Mars, watch for the rising of the planet Mercury. Sunday, June 9 An hour before sunup Monday look for Saturn in ESE, 8 degrees to Moon's upper right. Mercury is just rising in ENE, 4 degrees to Mars' lower right. The Mercury-Mars duo is higher and easier from S states. Although Mercury is 24 degrees from Sun, its farthest for this apparition, it remains very low in the bright glow of twilight. Use binoculars. Monday, June 10 At intervals of just over 19 months, Venus, orbiting on an "inside track", passes nearly between Earth and Sun and overtakes our slower planet. Such an event, which happens today, is called an inferior conjunction of Venus. That means Venus appears in conjunction with, or close to the Sun in our sky today, while it's actually some 67 million miles closer to us. In the weeks around inferior conjunction, Venus changes from an evening to a morning "star." After today, the next inferior conjunction of Venus occurs on January 16, 1998. Midway between now and then, on April 2, 1997, Venus will pass superior conjunction, beyond the Sun, and soon thereafter will emerge as an evening "star." Tuesday, June 11 Here are instructions for getting an early look at what may become next year's bright comet. Using binoculars 2-1/2 hours before sunrise on Wednesday, "star hop" from bright Jupiter in the south to Comet Hale-Bopp. Nearly 1.7 degrees above and slightly left of Jupiter is the 3rd-magnitude star Pi Sagittarii, the brightest and leftmost star in the bowl of the "Teaspoon." In the handle 4.2 degrees to Pi's upper left is the 4th-mag. star Rho-1. Just 1.9 degrees above Rho-1 is 4.6-mag. Upsilon. Finally, 2.4 degrees upper right of Upsilon in the "One O'Clock" direction is Comet Hale-Bopp, appearing as a hazy patch of light of about 7th- magnitude. Hale-Bopp appears 9.2 degrees NNE of Jupiter Wednesday. Moving 0.3 degrees WNW per day in June, the comet on June 27 will pass 10.5 degrees due north of Jupiter, directly above the planet when it passes due south that morning. An hour before sunup on Wednesday, Jupiter is in SSW, Saturn in ESE, and a pretty crescent Moon is low, a little N of due east. Using binoculars, check the ENE horizon about 20 degrees to Moon's lower left. Watch for Mercury rising 3.6 degrees to Mars' lower right, and the Pleiades cluster 4 degrees to Mars' upper left. Wednesday, June 12 An hour before sunup on Thursday, from a place with an unobstructed view, locate the last easy old crescent Moon very low in ENE. With horns pointing south, the crescent is tipped like a bowl nearly on its side. Using binoculars find Mars 8 or 9 degrees to Moon's left, and the Pleiades cluster about 4 degrees to Mars' upper left. Watch for the rising of Mercury some 6 or 7 degrees to Moon's lower left and 3.4 degrees lower right of Mars. Thursday, June 13 If the air is very transparent near the horizon 1-1/2 hours before sunup on Thursday, use binoculars to find the Pleiades rising some 30 degrees N of east. In the next 15 to 30 minutes, watch for Mars rising 4 degrees below the Pleaides, and Mercury rising 3 degrees lower right of Mars. By now it's only an hour before sunup and the Moon still isn't up yet. By half an hour before sunup the very thin old Moon is barely up in ENE, 5 degrees lower left of Mercury. Friday, June 14 An hour after sunset yellow-orange Arcturus, brightest star in June's night sky, is near its high point in the south. Blue-white Vega, atop the Summer Triangle, is in ENE halfway from horizon to overhead. Deneb in NE and Altair in E complete the Triangle, which is up all night from now through early August. Saturday, June 15 The Moon is New today at 9:36 p.m. EDT. The Moon passes well south of the Sun's disk, as you'll know when you observe the tilt of the young crescent on Monday. Sunday, June 16 Observers in Hawaii have a good chance to be the first on our planet to see the thin young Moon with unaided eye. If you're there, look for the 28-hour crescent very low in WNW 20 minutes after sunset today. The mainland 48 states will have to wait until early Monday evening for their first naked-eye view of the young Moon. Monday, June 17 Half an hour after sunset the young Moon is very low in WNW. The crescent with horns pointing south appears like a bowl tipped nearly on its side. From Michigan, the Moon is 48 hours old and 22 degrees from the Sun, so it's bright and relatively easy despite its very low altitude. But don't be late! Tuesday, June 18 An hour after sunset the 3-day-old crescent Moon is very low, about 15 degrees N of west. Look for the Gemini Twins, Pollux and Castor, 14 to 19 degrees to Moon's upper right. Using binoculars an hour before sunup on Wednesday, if you have an unobstructed view toward ENE, try for Mercury rising 3 degrees below Mars. Look for the Pleiades 6 degrees above Mars. Within next half hour, try for Venus rising 8 degrees lower left of Mercury. Most difficult is Aldebaran 4 degrees below Mercury and 6 degrees upper right of Venus. Wednesday, June 19 Two asteroids are now within easy reach of binoculars. Tonight we'll hunt for Ceres, the largest asteroid. Wait until nightfall, when the sky is very dark, then locate the reddish first-magnitude star Antares, low, east of due south. It is flanked by two 3rd-mag. stars, Sigma Scorpii 2 degrees to upper right, and Tau, just over 2 degrees to lower left. To the upper right of Antares, nearly 6 degrees past Sigma, is 2nd-mag. Delta Scorpii, the middle and brightest star of a slightly curved, nearly vertical line of three stars marking the Scorpion's head. The top star, 3rd-mag. Beta, is 3 degrees upper left of Delta. Just 1.6 degrees left of Beta is 4th-mag. Nu. Tonight and Thursday, the 7.5-mag. asteroid Ceres passes within 0.5 degree above Nu. Thursday: How to find asteroid Vesta, mag. 6.3. Thursday, June 20 Summer begins tonight at 10:24 p.m. EDT. An hour after sunset, the 5-day-old crescent Moon is in west with Regulus, heart of Leo, about 7 degrees to its upper left. At nightfall we'll use binoculars to locate Vesta. Although it has faded from six weeks ago, it remains the brightest asteroid. Locate the first-mag. bluish star Spica in SW, 33 degrees below the even brighter zero-mag. yellow-orange star Arcturus. Also find Antares, the reddish first-mag. star low, a little E of due south. Between Spica and Antares, not far above the midpoint of the line connecting them, find two stars of 3rd magnitude, Alpha and Beta in Libra. They are just west of due south at nightfall, with Beta 9 degrees upper left of Alpha. Next, find the 4th-mag. star Mu in Virgo, 9 degrees upper right of Beta and nearly 11 degrees upper right of Alpha. For the rest of this week, asteroid Vesta is within 3 degrees lower left of Mu Virginis, and just inside one corner of the triangle formed by Alpha and Beta Librae and Mu Virginis. Friday, June 21 An hour after sunset, the fat crescent Moon is in WSW, with Regulus, heart of Leo, 8 degrees to its right. Tonight through Tuesday, the Moon is in excellent view through binoculars and telescopes. Near the terminator (day-night boundary), the Sun is just rising over the lunar landscape, causing the Moon's surface features to cast very long shadows, exaggerating the heights of crater walls, mountains, and ridges, and the depths of craters. Tonight in the lunar northern hemisphere, the broad expanse of the Sea of Serenity lies astride the terminator, and the Sun is just rising on the craters Aristoteles and Eudoxus. Tonight and Saturday, if the sky is clear, Michigan State University Observatory will be open after the Abrams Planetarium showing of "Through the Eyes of Hubble." Saturday, June 22 One-and-a-quarter hours before sunrise, look low in ENE for the Pleiades cluster with Mars 9 degrees to its lower left. Binoculars give the best view of what follows, if you have a clear view of the horizon. By an hour before sunup can you see Mercury rising 6 degrees to Mercury's lower left? In another 10 minutes, look for Venus 1.6 degrees to Mercury's lower right, and Aldebaran 4 degrees to Venus' right. Bright Jupiter is easy to see in SW. If you can still see Saturn in SE, that''s five planets in view simultaneously! Venus, Mars, and Aldebaran will get higher and easier to see each morning, while Mercury gets lower. Sunday, June 23 Around sunset, the Moon is approaching First Quarter phase, its right half illuminated and showing spectacular detail in binoculars and telescopes. Along the terminator tonight are the walled plain Archimedes in the lunar north, and the close trio of craters Ptolemaeus, Alphonsus, and Arzachel just south of the Moon's center. South of Archimedes, the Apennine "mountain range" casts long shadows over the Mare Imbrium plain. Using binoculars, watch the ENE horizon an hour before sunup Monday for the rising of Mercury, Venus, and Aldebaran. Venus is 6 degrees to Mars' lower left, Aldebaran is 6 degrees to Mars' lower right and 4 degrees right of Venus. Mercury is within 3 degrees left of Venus. As sunrise approaches, binoculars show the crescent Venus only 6 percent lit. Monday, June 24 An hour after sunset, first-magnitude Spica is in SSW, 10 degrees left of the Moon. Wait a few hours until Jupiter passes due south, and use binoculars to see Comet Hale-Bopp about 10 degrees almost directly above Jupiter. The comet, predicted to be about 7th magnitude now, is moving WNW about 1/3 of a degree per day and will pass 0.6 degree north of a 5.4-mag. star on the morning of June 27. Tuesday, June 25 An hour after sunset, the waxing gibbous Moon is in SW with Spica about 4 degrees to its lower right. An hour before sunrise on Wednesday, look for brilliant Venus just risen in ENE. Mars is about 4-1/2 degrees above it, and Aldebaran just over 3 degrees to Venus' right. Now through July 10, Venus lingers no farther than Aldebaran than it is now, while both will get higher and easier to see! Wednesday, June 26 An hour before sunrise for the rest of June, watch Mars and Venus remain 4 degrees apart, with Mars passing upper left of Venus. Aldebaran is 3 degrees right of Venus on Thursday; they'll be within 2.4 degrees July 2-4. Thursday, June 27 For good quality telescopes: Overnight tonight, from 2:22 a.m. to 4:38 a.m. EDT (11:22 p.m. to 1:38 a.m. PDT), the shadow of Jupiter's satellite Io appears as a tiny black dot marching across the planet's disk from the planet's east limb to the west. Io itself follows its shadow by 9 minutes; start watching well before 2:31 a.m. EDT (11:31 p.m. PDT) to follow Io as a "star" approaching Jupiter until it merges with the east limb. Friday, June 28 One hour after sunset, Moon is in SSE with Antares, heart of the Scorpion, 8 degrees to its lower right. By three hours before sunup on Saturday, they're still 8 degrees apart, but in the SW with Antares to Moon's lower left. Saturday, June 29 An hour after sunset, Moon is in SE to SSE. Antares is 16 degrees to Moon's right, while bright Jupiter is very low in SE, 20 degrees to Moon's lower left. Sunday, June 30 Tonight's "Blue Moon" (second Full Moon this month) rises before sunset and is low in SE as the sky darkens. Note Jupiter about 6 degrees below the Moon. They'll be up for the rest of the night, closing to just over 4 degrees apart by dawn on Monday. Monday, July 1 Watch for the Moon's rising in ESE early this eveing -- within 20 minutes after sunset across the northern U.S., and within 35 minutes after sunset from Miami and SanDiego. The Moon is just past Full, and Jupiter is about 12 degrees to its upper right. ********** end of Skywatcher's Diary for June 1996 **********