THE SOUTHWORTH PLANETARIUM
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70 Falmouth Street Portland, Maine 04103
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Founded January 1970
"The Sun is middle aged and look how active it is!"
THE DAILY ASTRONOMER
Monday, May 2, 2016
May 2016 Night Sky Calendar
Now, May begins! Astronomically, we're entering the second full month of Spring. In New England, we're simply continuing to trudge through late winter. Of course, this month, the Mercurian transit is the big news. We’ve been focusing on it ad nauseum for the last couple months and are as giddy as a gadflys on green glens that this event is about to actually happen. If that transit is not enough to slack our astronomical thirst, we'll also experience a Martian opposition, a meteor shower consisting of Comet Halley fragments and the summer stars are rising as the winter patterns exit stage west.
On occasion, we'll post a photo and caption of a constellation that is either leaving or about to traipse onto our evening stage.
Moreover, we're also posting Monday's "Daily Astronomer" on Saturday evening, so it will be in your e-mail inboxes before we move into May.
THURSDAY, MAY 5: ETA AQUARID METEOR SHOWER PEAKS (BRONZE EVENT!)
Remember Halley's comet? It is currently moving slowly away from the Sun, but will turn around on December 9, 2023 in preparation for its 2061 return to the inner solar system. If you're not inclined to wait so long for its next performance, you can at least see pieces of the famous comet! The Eta Aquarid meteoroids are fragments of Comet Halley suspended in space. When Earth ploughs through this stream, the particles descend through the atmosphere and produce the lights we perceive as the Eta Aquarid meteors. These are so named as they appear to emanate from a point near Eta Aquari, a star within the constellation Aquarius. Eta Aquarid meteors and the Orionid meteors (October) both originate from Comet Halley. It might be awhile before we see the most famous comet of them all, but at least we can see pieces of it slicing through the sky tonight. Expect 10 - 30 meteors an hour, moving rapidly with persistent streams. As the moon is almost new, viewing conditions are favorable.
FRIDAY, MAY 6: NEW MOON
Beginning of lunation cycle 1155.
SUNDAY, MAY 8: MOON 0.47 DEGREES NNW OF ALDEBARAN
We'll see Taurus the Bull's alpha star very close to the waxing crescent moon. On the other side of the world, the moon will appear to "occult" Aldebaran. An occultation is the movement of a closer body directly in front of a more distant one. The moon can only occult four "first magnitude," (the brightest) stars: Aldebaran (Taurus), Antares (Scorpius), Regulus (Leo) and Spica (Virgo)
MONDAY, MAY 9: TRANSIT OF MERCURY (PLATINUM EVENT!!!!)
For those who've just joined, we assign celestial events "medals." The event we deem to be the month's most important event gets the "gold," the second more important is "silver," and the third is designated "bronze," However, on occasion we will award the very special events the "platinum." The transit of Mercury is just such an event. For the first time since November 2006, Mercury will appear to move in front of the Sun.
The following is a time table of the event:
CONTACT I: 7:13:29 a.m. (The moment when Mercury touches the Sun. We then see Mercury moving in front of the Sun.)
CONTACT II: 7:16:41 a.m. (The first moment when Mercury is entirely visible against the Sun.)
GREATEST TRANSIT: 10:57:46 a.m. (The moment when Mercury is closest to the Sun's center.)
CONTACT III : 2:38:05 p.m. (The last moment when Mercury is entirely visible against the Sun.)
CONTACT IV: 2:41:17 p.m. (The transit ends.)
The next transit of Mercury occurs on November 11, 2019.
If you would like more information about this event, please consult the Southworth Planetarium's "Transit of Mercury" module: http://usm.maine.edu/planet/da-april-11-2016-mercurian-transit-module
Goodbye, Orion. The giant hunter loiters over in the western, early evening sky and by the middle of the month, will vanish in the twilight. Expect Orion to return to the eastern, pre-dawn sky by early August
MONDAY, MAY 9: JUPITER STATIONARY
Planets never stop! Instead, a planet's migration across the sky will appear to halt as a consequence of Earth's orbital motion. A planet's "prograde" motion is west to east. Its "retrograde" path is west to east. A superior planet -one that is farther from the Sun than Earth- will appear to halt and then go retrograde prior to reaching opposition, when the planet on the far side of Earth relative to the Sun. The retrograde motion will continue for awhile after opposition before the planet "halts" again before resuming prograde motion. Jupiter was at opposition on March 8th and, almost two months later, its motion will once again be west to east.
THURSDAY, MAY 12: MOON 4.7 DEGREES SOUTH OF BEEHIVE CLUSTER
See the moon less than five degrees south of Prasepe, the Beehive Star Cluster. The only prominent feature in Cancer the Crab, this star cluster resembles a faint, luminous circle just to the east of Leo the Lion's sickle asterism. The moon will almost be at the quarter phase, so it will not wholly obscure the star cluster.
A close-up view of the Praesepe Star Cluster. It is also known as the "Beehive Star Cluster" as it resembles a bee swarm when observed telescopically.
FRIDAY, MAY 13: FIRST QUARTER MOON
FRIDAY, MAY 13: SUN ENTERS TAURUS
Now, spring begins in earnest. The westernmost of the winter constellations is concealed by the Sun. Taurus the Bull is associated mythologically with both the famous Minotaur and the bull that sired it. The Sun continues its ascent into the sky and will reach its solstice apex within five weeks. Taurus is one of the thirteen constellations through which the Sun appears to travel each year. The ecliptic constellations are TAURUS THE BULL, 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 and Aries the Ram. The Sun will enter Gemini the Twins on June 21st.
SUNDAY, MAY 15: MOON 1.9 DEGREES SSW OF JUPITER (SILVER EVENT!!)
The gibbous moon joins Jupiter in the evening sky. They will both set after midnight. One will have no trouble whatsoever finding brilliant Jupiter poised "above" the gibbous moon tonight.
WEDNESDAY, MAY 18: MOON 4.9 DEGREES NNE OF SPICA
Spica, the alpha star in Virgo the Maiden, is one of the four very bright stars which the moon can occult (See May 8th). Tonight, one will find the gibbous moon north of Spica.
See the moon to the north-northeast of Spica tonight. Spica represents the ear of wheat that Virgo holds in her right hand. Virgo is the daughter of Demeter (Roman: Ceres), the goddess of the harvest.
SATURDAY, MAY 21: FULL MOON
Today's full moon is a "blue moon," but not in the traditional sense. By convention, a blue moon is the second full moon in a single month. We know that there are not two full moons in May 2016. However, this spring we will have four full moons! March 23, April 22, May 21 and June 20th. (The June 20th full moon occurs less than half a day before the solstice.) Most seasons have only three full moons. However, in seven out of nineteen years, a year will have thirteen full moons, so that one season must have four. This year, spring has four full moons. The third of these four seasonal full moons is called a "blue moon." The first mention of this definition was in a 1937 Maine Farmers' Almanac! This full moon is a "blue moon," but perhaps not the blue moon with which most people are familiar.
SUNDAY, MAY 22: MARS AT OPPOSITION (GOLD EVENT!!!)
We've been watching Mars growing brighter over the last couple of months. Now, the red planet glows at its maximum brightness for 2016 as it moves into opposition. A planet is at opposition when Earth passes directly between it and the Sun. Around this time. the planet is at its closest point to Earth. Mars will actually be closest to Earth on May 30th, as Earth is presently moving toward aphelion, its greatest distance from the Sun. Therefore, even after the opposition, Earth will continue to move slightly closer to Mars. By May 30th, Mars and Earth will reach their minimum separation distance of 46.7 million miles. As Mars is comparatively close to Earth, it will appear as bright as Jupiter! (For more information, consult our "Planet Watch" segment.)
SUNDAY, MAY 22: MOON 3.2 DEGREES NORTH OF SATURN
See Saturn and the waning gibbous moon tonight. They'll rise in the mid evening and remain visible all night. Although Saturn won't be as brilliant as Mars or Jupiter, it is increasing in brightness as it approaches its June 3rd opposition.
Now that May has arrived, the Summer Triangle will rise in the late evening, just as Orion and his entourage set in the western sky. The Summer Triangle consists of the three stars Deneb, Vega and Altair. Deneb marks the tail of Cygnus the Swan. Vega represents the tip of Lyra the Harp. Altair is the eye of Aquila the Eagle.
SUNDAY, MAY 29: LAST QUARTER MOON
PLANET WATCH
MERCURY (ARIES-TAURUS) is not visible during the first half of May, except for the May 9th transit. During the second half of May, Mercury ascends in the eastern early morning sky and brightens dramatically. VERDICT: Well, if you miss seeing Mercury moving across the Sun's face, at least you can observe it in the pre-dawn sky. Best to wait until the last week of May.
VENUS: Not visible. While Venus does return to our evening sky in very late July, one should wait until early August to find it. VERDICT: Well, nothing to see here, we fear.
MARS: (PICK PLANET!) (LIBRA-SCORPIUS) The red planet glows bright this month. On the 22nd, Mars is at opposition and at its brightest for 2016. By month's end, Mars rises around sunset and sets around sunrise. VERDICT: This is the best time of the year to see our neighbor world! Look up almost any time of night this month and Mars will likely be up there somewhere.
JUPITER: (LEO) Generally, Jupiter outshines all the planets, save Venus. By the third week of May, Mars is equally bright. Jupiter sets after midnight and remains a brilliant evening sky planet. VERDICT: The giant planet is easy to see this evening and in the post-midnight western sky. Look beneath Leo and see Jupiter!
SATURN: (SAGITTARIUS) The most distant naked eye planet is growing brighter this month as it approaches its June 3rd opposition. Even though it is fainter than Mars and Jupiter, Saturn is still conspicuous. Saturn rises in the early evening and will be almost at opposition by month's end. VERDICT: Saturn is another easy planet to find. It won't dazzle you like Jupiter or Mars, but will still be pleasing to the eye, particularly if you have a telescope.
PLANETS IN ORDER OF DESCENDING BRIGHTNESS
MAY 1:
JUPITER - MARS - SATURN
MAY 30:
JUPITER/MARS (TIED) - SATURN - MERCURY