The good news? Summer officially begins with the Summer Solstice on Tuesday June 21 at 5:14 a.m. EDT. The bad news? We won’t dwell on it because there will be weeks of long summer days to enjoy before we actually notice, but our daylight hours will begin to slowly decrease from the SS until the Winter Solstice in December. The Earth’s axis is tilted 23.5 degrees from the plane of the planetary orbits around the Sun, thus the Northern Hemisphere leans toward the Sun at this time of the year. The combination of increased solar radiation from the high Sun angle and the longer period of daylight combine to bring us our summer season. We normally do not get into our warmest weather until July as it takes some time for the Earth to absorb this increased energy input. Those of us living near Lake Superior find both the land and water temperature lagging a little farther behind than points farther inland, but we enjoy the added warmth once fall arrives.
All four naked-eye planets (that is, planets one can see without using a telescope or binoculars) will be on display this month. They will be visible 45 minutes before sunrise and their line up will match the correct order of their actual distances from the Sun. By the week of June 17, they will be joined by Mercury and that is where we will start. To see this unique lineup, locate Mercury close to the horizon in the ENE. A telescopic view will show it to be 36 percent illuminated at a magnitude of +0.5 but it will continue getting brighter throughout the month. Slightly higher and to the south (or right) of Mercury will be Venus which will appear a much brighter -3.8 mag (remember, the smaller the number, the brighter the object appears). Higher above the horizon in an ESE direction one can find Mars residing in the constellation of Aquarius at a much dimmer +0.8 magnitude. The Waning Crescent Moon will be just to the right of Mars on June 22. Jupiter can be found just above the old Crescent Moon on June 21, but being second in brightness to Venus shining at -2.9 mag, it won’t be hard to find even without the Moon assist. Neptune (mag +7.8) will require binoculars to locate just above and to the left of the Last Quarter Moon on June 20, and Uranus will appear to the East after mid-month. Uranus will be a challenge as it will be near the naked eye limit of visibility at +5.6 mag. Look for it between Venus and the last crescent moon on June 24 when it will be a third closer to the Moon than to Venus. The Earth will not be totally left out of this grouping if we let the Moon represent us – the waning crescent Moon can substitute for our Blue Marble when it appears between Venus and Mars on June 23-25.
The rest of the Lunar highlights not already mentioned include the First Quarter on June 7, the Full Moon on June 14 (when it will also be at perigee or closest approach to the Earth at 222,098 miles at 7 p.m. EDT), and the New Moon will take place on June 28 (about three hours before the most distant Moon of the year when it will be 252,637 miles from the Earth).
For the June observing challenge, it will be helpful to use binoculars. On June 23, 45 minutes before sunrise, Venus and Mercury will be just 10 degrees apart, or one the width of a fist held at arm’s length. By contrast, the Mercury to Neptune alignment described above will span 105 degrees, or just about ten fist- widths. For more information on locating faint planets, visit the Extra Content Page at abramsplanetarium.org/msta/.
With the evening sky being rather void of planetary observations this month, we will leave you one other viewing challenge for late in the month. In the WNW 30 minutes after sunset, one should be able to see a very young crescent Moon on June 29 and 30. On the 29th, it will appear very close to the horizon just under the twin stars Castor and Pollux in Gemini, the Twins. On June 30th, the Twins will be just to the right, or north of the Moon.
A little less challenging but no less enjoyable to observe in the night sky, be sure to seek out the Summer Triangle embedded in the Milky Way. Comprised of the brightest starts in Cygnus the Swan (Deneb), Aquila, the Eagle (Altair), and Lyra, the Harp (Vega), it is one of the most well known asterisms (an asterism is a grouping of stars that form a pattern but are not actually constellations. The Big Dipper is a good example – it is the most recognizable part of the much larger grouping of Ursa Major, the Great Bear).
Compiled by Ken Raisanen of WOAS-FM – information provided by Abrams Planetarium Sky Calendar, Michigan State University. More information and subscriptioan information can be found on their website at http://abramsplanetarium.org/skycalendar/ or on Twitter at http://twitter.com/AbramsSkyNotes. Yearly subscriptions cost $12 and can be started anytime.
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