Astronomy Club of Asheville June 2018 Sky Events

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1 June 2018 Sky Events The Planets this Month - page 2 June 14 th Dusk s Venus, Mercury and a Sliver of Moon page 5 June 27 th Conjunction of the Full Moon with Saturn page 6 Planet Highlights - page 7 Moon Phases - page 9 Asteroid Vesta Reaches Opposition page 10 June 21 st - the Summer Solstice - page 12 The Changing Aspects of Saturn s Rings page 16

2 June 2018 Sky Events the Planets June 2018 provides views of 3 naked eye planets for early evening observers Mercury, Venus and Jupiter and those willing to stay up past midnight (and earlier by month s end) can add Saturn and Mars. Given that the asteroid Vesta, enjoying its brightest apparition in decades, joins the show in late evening, sky watchers have plenty of attractions on offer this month. Mercury emerges from a June 6 th superior conjunction (passing behind the Sun as seen from Earth) into early evening skies by mid-month. Glowing at magnitude -1.0, it fades to 0.0 by the end of the month, visible low in the W-NW after sunset. Venus transitions from Cancer into Gemini in June, blazing in the west at magnitude One hour after dark, both Venus and Mercury will disappear either below the horizon or into the horizon s murky atmosphere, so catch them early.

3 June 2018 Sky Events the Planets Against the background of the constellation Libra, Jupiter passed through opposition in May its closest position to the Earth for This most dynamic of all solar system objects is hardly past its best, though, and in June will accompany observers for most of the night. Look for bright Jupiter, glowing at magnitude -2.5, after sunset in the southeast. Situated just above the teapot asterism of Sagittarius, Saturn will reach opposition on June 27 th. Although this ringed planet rises near 11:00 p.m. on June 1 st and then progressively earlier each night, those with telescopic ambitions must wait an hourplus for crisp views above the unsteady air near the horizon. As seen from the Earth, the view of Saturn s ring system changes drastically as the planet travels through its nearly 30 year solar orbit. Every 15 years, our two orbits align and the ring plane opens its maximum towards us nearly 27 degrees.

4 June 2018 Sky Events the Planets Such views won t occur again until 2032, so place Saturn near the top of your summer observing list to enjoy superb views of this true Lord of the Rings. After suffering for years from a lackluster orbital alignment, Mars is nearing its closest and largest approach to the Earth since 2003 and will not again be as close until Rising after midnight until late this month, take time to observe the Red Planet over the next two months as it begins to brighten and increase in angular size, and revealing more planetary detail. Uranus and Neptune are now both early morning objects. Find charts to track these two ice giants motion here:

5 June 14 th -15 th 2018 the Planets Dusk s Venus, Mercury and a Sliver of Moon On the evening of Thursday, June 14 th, bright Venus will be your guidepost to find two challenging objects low to the W-NW horizon: a 1 day-old crescent Moon, and Mercury, which is emerging into dusk s skies from its superior conjunction (passing behind the Sun as seen from Earth) the previous week. While the -4.0 magnitude beacon of Venus will grab your attention, binoculars may be necessary to discern fainter Mercury and the sliver of Moon through twilight s glow. With a low view to the W-NW, try your luck about 9:15 p.m., some 30 minutes after sunset, or again on the following night, Friday the 15 th, when the Moon will be higher and thus easier to find. Image courtesy of Sky & Telescope

6 June 27 th 2018 the Planets Conjunction of the Full Moon with Saturn Reaching opposition on June 27 th (located opposite the Sun as seen from Earth and its closest approach of the year), Saturn will celebrate this annual orbital milestone by closely joining a near Full Moon. Image courtesy of Sky & Telescope On the evening of Wednesday, June 27 th, these two objects will be separated by just 1 degree, but don t be fooled by their proximity in the sky on this night Saturn lies nearly 841 million miles more distant than the Moon!

7 June 2018 Planet Highlights Chart courtesy of Sky & Telescope

8 June 2018 Planet Highlights Movement of the Sun, Moon and Planets this month Chart courtesy of Sky & Telescope

9 Moon Highlights June 2018 ** ** The Strawberry Moon Times shown are in Universal Time (UT) subtract 4 hours to convert to EDT Illustration and info courtesy of Sky & Telescope

10 June 2018 Sky Events Asteroid Vesta Reaches Opposition The brightest asteroid Vesta reaches opposition (positioned opposite the Earth from the Sun) on June 19 th. The 6 th magnitude object is found in the constellation Sagittarius at the beginning of June and transitions into Ophiuchus late this month. With a diameter of 525 km (326 mi) Vesta is the 2 nd most massive object in the asteroid belt, surpassed only by dwarf planet Ceres. At opposition, Vesta will be visible the entire night, shining at magnitude 5.3 its brightest apparition until 2031 and a naked eye find in dark conditions. Image of Vesta taken by the Dawn spacecraft in 2012

11 June 2018 Sky Events Asteroid Vesta Reaches Opposition The paths of Vesta and nearby Saturn this month, both located rising in southeast skies at nightfall slightly above the teapot asterism in Sagittarius Chart courtesy of Sky & Telescope

12 June 2018 Sky Events June 21 st, 2018 Summer Solstice The northern hemisphere s summer solstice occurs on Thursday, June 21 st at 6:07 a.m. EDT. It s the longest day (and shortest night) of the year in the northern hemisphere. The Sun s position on the summer solstice in the Asheville area reaches 2 extremes in altitude and azimuth (the following values are rounded): 1. First the Sun rises 30 north of east and sets 30 north of west on the summer solstice, compared to 30 south of east and 30 south of west on the winter solstice; that s a 60 swing. 2. Next the Sun rises 78 above the horizon at high solar noon on the summer solstice, compared to only 31 on the winter solstice; that s a 47 swing (Earth s 23½ axial tilt times 2).

13 June 2018 Sky Events June 21 st, 2018 Summer Solstice Translation: At the summer solstice the Sun takes not only a longer path across the sky but also a much higher path across the sky, yielding a much longer daylight period, with the Sun s radiation at a more intense angle.

14 June 2018 Sky Events June 21 st, 2018 Summer Solstice It s both the Earth s 23½ axial tilt and its orbit about our star that cause the seasons.

15 June 2018 Sky Events June 21 st, 2018 Summer Solstice NE E Montage of three sunrises from a small Greek island SE Yes, the Sun rises in the due east and sets in the due west but only on two days per year on the equinoxes!

16 June 2018 Sky Events the Planets The Changing Aspect of Saturn s Rings As seen from the Earth, the view of Saturn s ring system changes drastically as the ringed planet travels through its nearly 30 year solar orbit!

17 June 2018 Sky Events the Planets The Changing Aspect of Saturn s Rings Reaching opposition on June 27 th, Saturn is 846 million miles away, or 75 light minutes away. Its disk is about 75,000 miles in diameter but its ring system is some 175,000 miles in diameter. Our solar system s Lord of the Rings In June 2018, the north face of Saturn s rings will be tilted towards the Earth their maximum extent nearly 27 degrees and offering the best view of the rings until 2032! Amateur telescopes typically see up to 6 of Saturn s 62 moons, including its largest and most famous moon Titan.

18 June 2018 Sky Events the Planets Saturn s rings are tilted at a 27 angle in June test

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