THE SOUTHWORTH PLANETARIUM 207-780-4249 www.usm.maine.edu/planet 70 Falmouth Street Portland, Maine 04103 43.6667° N, 70.2667° W Founded January 1970 "Keeping a watchful eye on a complex sky" SATURDAY, JUNE 11: MOON 1.4 DEGREES SSW OF JUPITER Jupiter draws closer to the Sun each night. Tonight, we'll see the giant planet close to the waxing crescent moon in the western evening sky. An easy sight for those who prefer to observe celestial objects at a decent hour. SUNDAY, JUNE 12: FIRST QUARTER MOON SUNDAY, JUNE 12: EQUATION OF TIME EQUALS 0 What the devil does this statement mean? Simply, the Sun will cross the meridian (due south) at noon time precisely. Most of the time, the Sun crosses the meridian (or, reaches upper culmination) either before or just after noon. The time of upper culmination varies primarily because Earth's orbital is not perfectly circular and our orbital velocity is not constant. Today, however. when the clock strikes noon, the Sun will be due south and the day's shadows will be at minimum length. MONDAY, JUNE 13: MARS AND SATURN AT HELIOCENTRIC CONJUNCTION Again, nothing to see here. However, Mars and Saturn will be aligned relative to the Sun today! FRIDAY, JUNE 17: MOON 6.9 DEGREES NNE OF MARS The waxing gibbous moon is close to the red planet tonight. Even though Mars is slowly diminishing in brightness, it remains brighter than any night sky star and is quite easy to observe, especially as it appears so close to the moon. SUNDAY, JUNE 19: MOON 3.2 DEGREES N OF SATURN Though not as bright as Mars, Saturn remains a conspicuous object owing to its recent opposition. Also, you might want to observe the moon on June 18th, when it will appear between Mars and Saturn. MONDAY, JUNE 20: SUMMER SOLSTICE (GOLD EVENT!!!) What a beautiful day! Today, the Sun attains its highest altitude in our sky as a consequence of Earth's polar alignment. The planet is tilted on its axis relative to the vertical by 23.5 degrees or thereabouts. Consequently. as Earth revolves around the Sun, the north pole's alignment relative to the Sun always changes. On the summer (June) solstice, it points toward the Sun. Six months later on the winter (December) solstice, the north pole points away from the Sun. Happy Astronomical Summer! MONDAY, JUNE 20: FULL MOON It is often said that the moon is low in the summer and high in the winter. This statement is certainly true about the FULL MOON. The moon is travels along the ecliptic band, a thin region surrounding the the ecliptic, the Sun's apparent annual path through the sky. This part of the ecliptic the Sun occupies in the summer is high and the part it occupies in the winter is low. The summer and winter sections of the ecliptic are 180 degrees apart. The full moon is 180 degrees away from the Sun. So, when the moon is full on or around the winter solstice, the Sun will be low and the moon will be high, as it will be positioned around the high point of the ecliptic. Conversely, the full moon on or around the summer solstice will be low along the ecliptic. Hence the expression: the moon in summer is low and the moon in winter is high. The June full moon's names are a beautiful array of sweet sobriquets, harkening back to the golden age when fellowships were universal, conflicts impossible, weather uniformly clement, crop yields copious (quite a feat without rain), and loveliness pervaded the land from summit to sea to valley. Although life today is a mite more gritty, we've retained the names of Honey moon, Milk moon, Strawberry moon and Rose moon. TUESDAY, JUNE 21: SUN ENTERS GEMINI The Sun leaves Taurus the Bull and enters Gemini the Twins. This apparent annual solar migration results directly from Earth's orbital motion around the Sun. As our planet whips around the fiery orb, our perspective on the stars changes. Presently, Earth is on the far side of the Sun relative to the Gemini stars, and therefore the Sun appears to move through that constellation. Each year, the Sun moves through thirteen constellations: those comprising the ecliptic, or the "zodiac." The ecliptic constellations are GEMINI THE TWINS, Cancer the Crab, Leo the Lion, Virgo the Maiden, Libra the Scales, Scorpius the Scorpion, Ophiuchus the Serpent Charmer, Sagittarius the Archer, Capricornus the Seagoat, Aquarius the Water Bearer, Pisces the Fish, Aries the Ram, and Taurus the Bull. The Sun will enter Cancer the Crab on July 20. MONDAY, JUNE 27: LAST QUARTER MOON THURSDAY, JUNE 30: MARS STATIONARY In the April 2016 Night Sky Calendar, the DA wrote for April 17th; *"No, Mars won't stop. The planets have been moving continuously for billions of years and will continue to do so for billions of more years. However, Mars will appear to stop moving in a prograde (eastward) fashion and then will begin retrograde (westward) motion as it approaches its May 22 opposition."* Mars has been moving in a retrograde loop since April 17th and will appear to become stationary again before resuming prograde motion. Note that a planet in prograde motion moves from west to east, while it moves from east to west when in retrograde. PLANET WATCH MERCURY: Mercury lurks in the pre-dawn eastern sky at month's beginning and reaches its greatest western elongation on June 5th. During the first half of June, Mercury brightens, but then will vanish into the morning twilight late this month. VERDICT: Find Mercury easily in the early morning sky early in June. By late June, don't bother. VENUS: Not visible at all this month. Technically, Venus will return to the evening sky by late July (very late July). However, we shouldn't expect to see Venus again until early August. VERDICT: Alas, nothing to see here. MARS: A gorgeous evening planet! Still bright throughout the month, even though it will be growing slightly dimmer as Earth moves away from Mars. VERDICT: See Mars easily all month! A beautiful red world in the southeastern evening sky. JUPITER: Losing a bit of its luster, but still quite bright, Jupiter begins the night in the western evening sky. We'll lose Jupiter to the dusk in September. Now, the behemoth planet remains an easy sight for those who prefer early night viewing. VERDICT: Simple to find and wonderful to see in the early evening. SATURN (Pick Planet): We don't often choose Saturn to be the pick planet, but this month it is at opposition and this designation seems appropriate. VERDICT: Though not as bright as Mars or Jupiter, Saturn is at its brightest of the year. Find it throughout the night. PLANETS IN ORDER OF DESCENDING BRIGHTNESS Early June: JUPITER/MARS (tie) - SATURN - MERCURY Mid-June JUPITER - MARS - MERCURY SATURN ------------------------------------------------------------------------ FROM THE CATACOMBS OF INFINITE KNOWLEDGE A refractor telescope uses lenses; a reflector telescope uses mirrors --------------------------------------------------------------------------