Seeing Stars with James Wooten: Comet ISON, Winter Solstice & the Geminid meteor shower

ev.owaThis is it. The final stargazing report of 2013. So let’s get to it, shall we?

Venus remains in the west at dusk for one more month. It outshines everything but the Sun and Moon, so you can begin observing it during deep twilight. Shortly after the new year begins, Venus shifts from the evening to the morning sky.

Jupiter will be up literally all night long early next month. In December 2013, then, it is not up at dusk but rises during the evening. Now you can see it rise in the northeast at about 8 p.m., just as Venus sets. By New Year’s Eve, Jupiter rises by 5:50 p.m., during twilight.

Mars remains in the morning sky. It continues to brighten a bit in the south at dawn.

Saturn has reappeared in the pre-dawn sky. Face southeast right before sunup to see it.

In December, the Big Dipper is below the horizon at dusk. As the Big Dipper sets, though, Cassiopeia rises. This is a pattern of five stars in a distinct W shape which lies directly across the North Star from the Big Dipper. Look for Cassiopeia high in the north on fall and winter evenings.

The Summer Triangle sets in the west. Watch for the Great Square of Pegasus almost overhead at dusk now and in the west by Christmas. Taurus, the bull, rises in the east. Look for the Pleiades star cluster above reddish Aldebaran. Dazzling Orion, the hunter, rises shortly after dusk (by month’s end, it is already up at dusk). As Orion enters the evening sky, we transition from the relatively dim evening skies of autumn to the brilliant stars of winter.

Unfortunately, it appears that Comet ISON did not survive its close passage to the Sun this past Thanksgiving. At 12:48 p.m. CST on Thurs., Nov. 28, ISON passed just 1.7 solar radii above the Sun’s surface. This proved to be too close, as the Sun’s gravity tore ISON apart, causing it to shed much of its gas and dust. This left only a small remaining fragment to continue on ISON’s orbital path, a fragment too small to put on a naked-eye show on December mornings. Binocular observers, though, can still give it a try.

You can still find information showing ISON’s position, or you can view the full path.

If ISON survives perihelion this Thanksgiving (it has about a 50/50 chance), we could see it quite well between Thanksgiving and Christmas. More on this in the December update.

Moon Phases in December 2013:

New: December 2, 6:21 pm
1st Quarter: December 9, 9:12 am
Full: December 17, 3:28 am
Last Quarter: December 25, 7:49 am

At 11:11 a.m. on Sat., Dec. 21, the Sun is directly overhead at the Tropic of Capricorn, the farthest point south where this is possible. This puts the Sun as low as possible in our sky, and marks the winter solstice. In the Southern Hemisphere, the Sun is as high as possible in the sky — this is the summer solstice for them.

Although the winter solstice is the shortest day, the earliest sunset occurred on about Dec. 2, and the latest sunrise will occur Jan. 10. That’s because the Earth speeds up on its orbit as it approaches perihelion (closest approach to the Sun) next month. This acceleration shifts sunrise, local noon, and sunset slightly later each day this month and next. The effect is smaller than that of the Sun taking a lower path across the sky, which normally dominates in causing earlier sunsets and later sunrises. But the Sun’s apparent path varies very little near the solstice itself, allowing the secondary effect of the Earth approaching the Sun to predominate. For most people, then, (those who witness sunset but sleep through sunrise), days will seem to lengthen throughout December, although they don’t really begin lengthening until Dec. 21.

The Geminid meteor shower peaks this month, as it does every December. Along with the Perseids in August, the Geminids are one of the two most reliable meteor showers, producing on average about 100 meteors per hour. The Geminids are unique among meteor showers because they are associated not with a comet but with an asteroid, 3200 Phaethon. This means that with Geminids, we see significant activity much earlier in the night than with other showers.

Most meteor showers peak in the hours immediately before dawn. This is because what plows through the debris field is the leading edge of the Earth, and that’s the side going from night into day. Since Phaethon is an asteroid, however, debris along its orbital path forms a shallower angle to Earth’s orbital path, meaning that we begin to face into the debris field as early as 9 or 10 p.m. Meteors will seem to “radiate” from the constellation Gemini, hence the name of the shower. However, they may appear anywhere in the sky.

As always, you see more meteors the farther you are from big city lights, which hide dimmer ones. Our George Observatory will be open at 5 p.m. on Friday night, Dec. 13, to 1 a.m. on Saturday morning, Dec. 14, for observing this meteor shower.

On most clear Saturday nights at the George Observatory, you can hear me do live star tours on the observation deck with a green laser pointer. If you’re there, listen for my announcement.

It’s Baktunalia! Astronomy VP Carolyn Sumners on why Dec. 21 is cause for celebration, not wild imagination

December 21, 2012: It’s not the End of the World — it’s the Baktunalia! It’s time for a celebration, not an apocalypse.

Here are the facts: The Maya long count calendar will go from 12.19.19.17.19 to 13.0.0.0.0 as we go from December 20 to December 21, 2012. So December 20 is New Baktun Eve and December 21 is New Baktun Day.

(FYI for those who like numbers: The five digits of the Mayan long count are base 20, except for the second number from the right, which is base 18. Our numbers are base 10. We have ones, tens, hundreds, and thousands. The Maya long count has kins, winals, tuns, katuns, and baktuns. For the Maya, a day is called a “kin.” Twenty kins make a winal. Eighteen winals, or 360 kins, equal a tun, making the tun about a year long. Twenty tuns make a katun and 20 katuns equal a baktun. Thirteen baktuns is just over 5,125 years.)

The Roman Saturnalia festival also occurred at this time — a celebration featuring food, gifts, and celebrations around the Winter Solstice. Early Christians could celebrate Christ’s birth on December 25, hiding their event within the Saturnalia festivities. Hence, I’m calling this year’s rare event a Baktunalia!

See 2012: Mayan Prophecies at the Burke Baker Planetarium

Did the Maya calendar-makers over 2,000 years ago plan for their long-count calendar to reach the 13th Baktun on December 21? This is possible, but it seems unlikely. However, December is the Winter Solstice, a day the Maya recognized as the shortest day and longest night of the year — the day when the sun rises furthest in the southeast, sets furthest in the southwest, and makes its lowest and shortest path across the southern sky in the Northern Hemisphere. The Maya astronomers observed the sun on the winter solstice to document its southernmost rising and the promise that the sun would now start moving northward. There would be another spring and a new growing season.

Unlike the Internet doomsday prophets, science does not support an apocalypse in 2012. Solar activity maximum is happening in 2013. Thus far, all natural disasters in 2012 have been within the normal range of activity on a geologically active planet with dynamic weather patterns.

But there is one interesting astronomical alignment. On December 21, the sun will reach its lowest point in the sky for the Northern Hemisphere while it is in front of a dark rift in the Milky Way and directly between Earth and the Milky Way Galaxy’s center. This alignment has been in place for several years, but is often cited by the doomsday prophets. The black hole near the galactic center has the same effect on us today as it does on any day. This alignment makes no difference. Nor is it significant on December 21. After all, the sun is its strongest on this date south of the equator.

Lost in all the apocalyptic talk are the very significant achievements of the Maya regarding both time-keeping and astronomy. In the Burke Baker Planetarium, we have a show called Mayan Prophecies that visits four classic Maya cities (Uxmal, Chichen Itza, Tikal, and Palenque), as they would have looked over a thousand years ago. At Uxmal, we see a Maya astronomer watching the sun’s rays entering the Temple of the Magician just two 20-day months before the sun would stand overhead and the rains would come. After this event, the astronomer could prepare farmers to plant their corn and the king to plan festivals.

At Chichen Itza, the feathered serpent god called Kukulcan would climb down his pyramid, El Castillo, on the first day of spring. Astronomers would then know when to have festivities with human sacrifices, trading human blood for the coming rains — all to appease Kukulcan and the rain god, Chaac. We actually show this sacrifice (tastefully) in the full dome and very up-close in the Mayan Prophecies planetarium show.

At Tikal (located in the lowlands of Guatemala), the astronomer would climb his pyramid, now called Temple 4, to watch the rising sun on December 21. When the sun rose over Temple 3, it marked the winter solstice. After this date, the astronomer knew that the sun would rise more to the north each day and that the rainy season would come again.

At Palenque, there are inscriptions inside major temples featuring trees for the seasons. The great King Pacal supposedly rose and journeyed to the heavens on December 21. Inscriptions at Palenque also explain the beginning of the long count cycle on a date we know now as August 13, 3114 BCE. Three temples at Palenque symbolize the three hearthstones of creation, with a central fire lit at the beginning of the current long count cycle. There are also three stars in our constellation Orion that represent these hearthstones.

For all their predictive power, the Maya astronomer could not foresee his own apocalypse, which happened over a thousand years ago. A combination of factors adding to decades of drought brought famine to the Classic Mayan cities. This great civilization, that had measured time and predicted the rains, collapsed and its people returned to the rainforest and mountains. The story of the Maya people is perhaps a greater predictor of the challenges we face in 2012 and beyond.

Fascinated? Discover how the Maya aligned their pyramids and temples to watch their sky gods and used interlocking calendars to record the past and predict the future in our Mayan Prophecies lecture. Dr. Carolyn Sumners will share how archaeological, historical and astronomical records were pieced together to learn more about the Maya. This lecture includes a viewing of film 2012: Mayan Prophecies. For lecture tickets, click here.

Seeing Stars with James Wooten: December 2012

Mars remains an evening object. It is low in the southwest at dusk.

Jupiter is now up all night long. Opposition — when Earth is directly between Jupiter and the Sun and Jupiter literally rises at sundown and sets at sunup — is Dec. 3. After that date, Jupiter only gets higher and more prominent in the evening sky. Face east/northeast at dusk and look for the brightest thing there (unless the Moon is also there), as Jupiter outshines all stars we see at night.

Sky Map November 2012

Venus remains in the east at dawn, continuing a spectacular morning apparition. It now appears a little closer to the horizon each morning.

Saturn is a little higher in the morning sky this month; look for it just above the much brighter Venus. Mercury is visible for the first half of the month at dawn.  Look just under Venus.

The autumn ‘intermission’ — when few bright stars are out at dusk — is over; brilliant winter stars enter the evening skies of December. Watch dazzling Orion rise as twilight ends. He rises with his three-starred belt almost vertical, halfway between reddish Betelgeuse and bluish Rigel. Orion’s belt points up to Aldebaran in Taurus, the Bull. This winter, the Bull also contains Jupiter.

Rising with Orion and far to his left are the twin stars Castor and Pollux, marking the heads of Gemini, the Twins.  By 8 p.m. in mid-month, the two Dog Stars have joined Orion. You can find Sirius, the brightest star we ever see at night, by drawing a line from Orion’s belt towards the horizon.

Moon Phases in December 2012:
Last Quarter                  December 6, 9:32 a.m.
New                               December 13, 2:41 a.m.
1st Quarter                    December 19, 11:19 p.m.
Full                                December 28, 4:22 a.m.

At 5:12 p.m. on Friday, Dec. 21, the Sun is directly overhead at the Tropic of Capricorn, the farthest point south at which it can be overhead. This puts the Sun as low as possible in our daytime sky, and as high as possible in the sky for anyone in the Southern Hemisphere. This also makes daytime as short as possible for us, and as long as possible for folks “down under.” Accordingly, this moment is the winter solstice in the Northern Hemisphere and the summer solstice in the Southern Hemisphere.

The Geminid Meteor Shower peaks this month, as it does every December. Along with the Perseids in August, the Geminids are one of the two most reliable meteor showers, producing on average about 100 meteors per hour. The Geminids are unique among meteor showers because they are associated not with a comet but with an asteroid, 3200 Phaethon. This means that with Geminids, we see significant activity much earlier in the night than with other showers.

Most meteor showers peak in the hours immediately before dawn. This is because what plows through the debris field is the leading edge of the Earth, and that’s the side going from night into day. Since Phaethon is an asteroid, however, debris along its orbital path forms a shallower angle to Earth’s orbital path, meaning that we begin to face into the debris field as early as 9 or 10 p.m. Meteors will seem to ‘radiate’ from the constellation Gemini, hence the name of the shower. However, they may appear anywhere in the sky.

As always, you see more meteors the farther you are from big city lights, which hide dimmer ones. Our George Observatory will be open Friday night, Dec. 14, into Saturday morning, Dec. 15, for observing this meteor shower.

On most clear Saturday nights at the George Observatory, you can hear me do live star tours on the observation deck with a green laser pointer. If you’re there, listen for my announcement.

To enjoy the stars in any weather from the comfort of the HMNS Planetarium, click here for a full schedule.

Would you like email updates on current events in the sky, at the planetarium, and at the George Observatory?  If so, send an email to astroinfo@hmns.org.

Go Stargazing! February Edition

Jupiter!
Creative Commons License photo credit: Joshua Bury

Jupiter leaves the evening sky this month.  You can still see it during the next two weeks if you face southwest at dusk and look for the brightest point of light there. Jupiter sets by 7:30 as February opens, so you must look soon after dusk to see it.   However, Jupiter sets earlier and earlier and appears lower and lower to the horizon each February night, and soon disappears into the sun’s glare.  On Tuesday, Feb. 16, observers with a clear view of the horizon during twilight can try to see a very close conjunction of Jupiter and Venus, which is slowly moving out of the sun’s glare.  By the end of the month, Earth and Jupiter are on opposite sides of the Sun and Jupiter is therefore invisible to us.

Mars has become an evening object.  It is now already up in the east-northeast by dusk.  Mars already outshines all stars in the night sky except the very brightest (Sirius), and will continue to brighten throughout February.  On Jan. 29, Mars came to opposition as Earth passed between Mars and the sun, putting Mars in our sky all night long.  Earth now starts to pull ahead of Mars on its faster orbit.  As a result, Mars is slightly dimmer each night for the rest of 2010.  However, during February, Mars remains about as bright as the brightest stars, and thus remains easy to see.

Saturn is now high in the southwest at dawn.  Although not as bright as Mars this month, Saturn is brightening as it approaches its own opposition in March.

Joseph Nollekens (1737 - 1823) Castor and Pollux front (V&A 2007)
Castor and Pollux
Creative Commons License photo credit: ketrin1407

Dazzling Orion is high in the south, reminding us that winter is here.  His belt points up to Aldebaran, the eye of Taurus, the Bull.  The Dog Stars, Sirius and Procyon, are below Orion in the east.  Sirius is the brightest star we ever see at night.  Gemini, the Twins, are to Orion’s left as he rises (and to his upper left once they appear to the south).  Look for two stars of equal brightness less than 5 degrees (three fingers at arms’ length) apart.  These are Castor and Pollux, marking the twins’ heads.  High in the northeast is Capella, the sixth brightest star ever seen at night.  On February and March evenings, look below Sirius and a bit to its right for Canopus, the second brightest star we ever see at night. This star is in the keel (bottom) of the legendary ship Argo.  Canopus is so far south that most Americans never get to see it.  We, however, are far enough to the south that it barely rises for us, remaining low on the southern horizon.

Moon Phases in February 2010:

Last Quarter                  February 5, 5:50 pm
New Moon                      February 13, 8:52 pm
1st Quarter                     February 21, 6:42 pm 
Full Moon                       February 28, 10:37 am

The new moon of Feb. 13 is the second new moon after the winter solstice.  Accordingly, it marks the Chinese New Year, beginning the Year of the Tiger.  (Correct for the time zone difference, and you’ll see that the date is February 14 in China).

Chinese New Year - Dragon
Creative Commons License photo credit: ajagendorf25