Star Map: November 2016

november2016

This star map shows the Houston sky at 8 pm CST on November 1, 6:30 pm CST on November 15, and dusk on November 30.  To use the map, put the direction you are facing at the bottom.

The Summer Triangle is high in the west.  The ‘teapot’ of Sagittarius sets in the southwest.  How long can you follow Saturn as it sets in twilight?  The Great Square of Pegasus is high in the east at dusk. To the south and east, we see a vast dim area of stars known as the ‘Celestial Sea’, where only Fomalhaut stands out. 

Venus is a little higher in the evening sky this month.    Look low in the west southwest in evening twilight.  Venus pulls away from Saturn, having passed it late last month.

Mars is now in the southwest at dusk.  Mars continues to fade each night as Earth leaves it farther and farther behind

Saturn  gradually drops into the Sun’s glare this month.  Visible to the right of Venus on November 1, Saturn sets earlier and earlier each night until it sets in twilight by Thanksgiving.  You’ll need a clear horizon to the west southwest to find it.  How long can you still see it?

Jupiter is much higher in the morning sky this month.  Look in the east southeast at dawn. 

Autumn represents sort of an ‘intermission’ in the sky, with bright summer stars setting at dusk, while bright winter patterns such as Orion won’t rise until later (Orion is up by about 10 now and about 9 mid-month).  The Summer Triangle is in the west.   Meanwhile, the Great Square of Pegasus is almost overhead.  The stars in the southern sky are much dimmer than those overhead and in the west because when you face south at dusk in November, you face out of the Milky Way plane.  The plane of our Galaxy follows a path from the Summer Triangle in the west through Cassiopeia in the north and over to the northeastern horizon.  

Constellations in the November southern sky are almost entirely devoid of bright stars.  They represent beasts and gods related to water, indicating that they are part of the ‘Celestial Sea’.  Examples are Aquarius, the Water Bearer and Pisces, the Fish.  Even Capricornus, the Goat, has a fish tail because he’s originally Ea, Babylonian god of the waters.  Below Aquarius is the one bright star in this area, Fomalhaut, marking the mouth of the Southern Fish.  Ancient Mesopotamians imagined that the Persian Gulf extended upwards into the sky, joining this ‘sea’ of dim stars. 

All of these celestial happenings are on show every Saturday at our George Observatory. Located in Brazos Bend State Park, the seclusion provides a nice dark sky, perfect for viewing stars. Docents and Observatory staff are available to help new star gazers discover amazing extra-terrestrial wonders.

Seeing Stars with James Wooten: Mars and Jupiter Shine Bright

This star map shows the Houston sky at 10 pm CDT on July 1, 9 pm CDT on July 15, and dusk on July 31.  To use the map, put the direction you are facing at the bottom. The Summer Triangle is high in the east.  This consists of the brightest stars in Cygnus, Lyra, and Aquila.  Scorpius, the Scorpion, is in the south, with the ‘teapot’ of Sagittarius to his left.  Leo, the Lion, sets in the west with Jupiter.  From the Big Dipper’s handle, ‘arc to Arcturus’ and ‘speed on to Spica’ in the southwest.  Mars and Saturn remain in the south at dusk.

This star map shows the Houston sky at 10 pm CDT on July 1, 9 pm CDT on July 15, and dusk on July 31. To use the map, put the direction you are facing at the bottom.
The Summer Triangle is high in the east. This consists of the brightest stars in Cygnus, Lyra, and Aquila. Scorpius, the Scorpion, is in the south, with the ‘teapot’ of Sagittarius to his left. Leo, the Lion, sets in the west with Jupiter. From the Big Dipper’s handle, ‘arc to Arcturus’ and ‘speed on to Spica’ in the southwest. Mars and Saturn remain in the south at dusk.

Jupiter is now in the west at dusk. It outshines all stars we ever see at night, so you can’t miss it.

Mars and Saturn are now in the south at dusk. As you watch them, Mars is to the right and is much brighter.

Although Mars continues to fade each night as Earth leaves it farther and farther behind, this month Mars still outshines all of the stars and even rivals Jupiter in brightness! By the end of the month, Mars begins to approach Saturn.

Venus is lost in the Sun’s glare and out of sight all month.

The Big Dipper is above the North Star, with its handle pointing up. From that handle, you can ‘arc to Arcturus’ and then ‘speed on to Spica’; those stars are in the west at dusk. Leo, the Lion, is also in the west at dusk.

Antares, brightest star of Scorpius, the Scorpion, is in the south, with the ‘teapot’ of Sagittarius to its left. Saturn is right above Antares. The Summer Triangle has fully risen in the east. The stars of summer are here.

Moon Phases
Moon Phases in July 2016:

New July 4, 6:01 a.m.

1st Quarter July 11, 7:52 p.m.

Full July 19, 5:57 p.m.

Last Quarter July 26, 6:00 p.m.

At 11:00 am on Monday, July 4, Earth is at aphelion. This means that on this date Earth is as far from the Sun as it will get this year. But all of us can feel how hot and sticky it is outside now, compared to January, when Earth was at its closest. This is because the Earth’s orbit is almost a circle; the difference between closest and farthest distance from the Sun is small. Indeed, Earth is only 1.6% farther than average from the Sun on July 4. The effect of Earth’s 23.5 degree tilt easily dominates the tiny effect of Earth’s varying distance from the Sun.

Also on July 4, the Juno spacecraft enters Jupiter orbit. For just over a year and a half, Juno will execute 37 orbits of Jupiter before a controlled orbit into Jupiter in February 2018. The spacecraft is designed to explore the inner composition of Jupiter, giving more information about what’s far beneath the cloud layers we see.

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. As of now, however, George is closed while Brazos Bend State park dries out from yet another round of floods on the Brazos River. The park could reopen as early as July 12.

Clear Skies!

James G. Wooten
Planetarium Astronomer
Houston Museum of Natural Science

Seeing Stars with James Wooten: Mars Brightest in the Sky During the Month of the Summer Solstice

June Starmap

Jupiter is now high in the southwest at dusk. It outshines all stars we ever see at night, so you can’t miss it. 

Mars and Saturn are now in the southeast at dusk. As you watch them rise, Mars is to the right and is much brighter. 

In fact, this month Mars outshines all of the stars and even rivals Jupiter in brightness! That’s because on May 22, Earth passed between the sun and Mars. That alignment is called ‘opposition’ because it puts Mars opposite the sun in our sky, making Mars visible literally all night long. It also makes Mars much brighter than normal in the sky, since we’re as close to it as we’ll ever get until Earth overtakes Mars again in 2018. Saturn came to opposition on June 3.

Venus is lost in the sun’s glare and out of sight all month. In fact, on June 6, Venus is directly behind the sun from our vantage point.

The Big Dipper is above the North Star, with its handle pointing up. From that handle, you can ‘arc to Arcturus’ and then ‘speed on to Spica’; those stars are in the south at dusk.  Leo, the Lion, is high in the west at dusk. Venus and Jupiter come together right in front of Leo’s face, marked by stars in the shape of a sickle, or a backwards question mark. 

Antares, brightest star of Scorpius, the Scorpion, is in the southeast, with the ‘teapot’ of Sagittarius rising behind it. Saturn is right above the scorpion’s head. The Summer Triangle has fully risen in the northeast. The stars of summer are here.

Moon Phases

Moon Phases in June 2016:

New: June 5, 10 p.m.

First Quarter: June 12, 3:10 a.m.

Full: June 20, 6:02 a.m.

Last Quarter: June 27, 1:19 p.m.

Earth at Aphelion:

At 5:34 pm on Monday, June 20, the sun is directly overhead as seen from the Tropic of Cancer, the farthest point north where the sun ever appears overhead. This means Earth’s North Pole is tilted towards the sun as much as possible towards the sun, and the sun appears higher at midday than on any other day of the year. We also have more daylight on June 20 than on any other day of the year. Therefore, we call June 20, 2016, the summer solstice. Below the equator, the sun is as low at midday as it ever gets, and there is less daylight than on any other day of the year. For them, this is the winter solstice. 

But if you’re paying close attention, you’ll notice that the latest sunset occurs at the end of the month, not on June 20. As Earth approaches aphelion (farthest distance from the Sun) on its slightly elliptical orbit, it slows down slightly. This causes both sunrise and sunset to occur a little later each day. This tiny effect actually prevails near the solstices because Earth’s tilt changes very little during that time. (Think of a sine wave; near the highest and lowest points, the curve looks fairly flat). Most of us sleep through sunrise and witness sunset, so we have the (wrong) impression that the days lengthen all the way to the end of June.

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. As of now, however, the George is closed while Brazos Bend State park dries out from yet another round of floods on the Brazos River. Stay tuned for updates.

Clear Skies!

Seeing Stars with James Wooten: Exciting Rare Mercury Transit Next Monday!

May Starmap

Jupiter is now high in the south at dusk. It outshines all stars we ever see at night, so you can’t miss it.

Mars and Saturn become late evening objects this month. Tonight, May 2, Mars rises in the southeast at 9:48 p.m. while Saturn comes up soon afterwards, at 10:24 p.m. By May 15, though, both planets rise during twilight, and on Memorial Day both are in the southeastern sky as soon as it gets dark. Mars and Saturn are still above the distinctive pattern of Scorpius, the scorpion. As you watch them rise, Mars is to the upper right and is much brighter.

In fact, this month, Mars outshines all of the stars and even rivals Jupiter in brightness! That’s because on May 22, Earth passes between the Sun and Mars. That alignment is called ‘opposition’ because it puts Mars opposite the Sun in our sky, making Mars visible literally all night long. It also makes Mars much brighter than normal in the sky, since we’re as close to it as we’ll ever get until Earth overtakes Mars again in 2018. Saturn comes to opposition June 3.

Venus is lost in the Sun’s glare and out of sight all month.

A swath of brilliant winter stars sets in the west at dusk. Orion, the Hunter, is still visible in the west as May begins. His two dogs, represented by Sirius and Procyon, are to his left.  Gemini, the Twins, are above Orion. The Big Dipper is above the North Star, with its handle pointing to the right. From that handle, you can ‘arc to Arcturus’ and then ‘speed on to Spica’; those stars are high in the east and in the south, respectively, at dusk. Leo, the Lion, passes almost overhead at dusk.

As Orion and his dogs set, look for Antares, the brightest star in Scorpius, the Scorpion, to rise in the southeast. Saturn and Mars will rise with the Scorpion’s head, above Antares. At the same time, Vega, brightest star of the Summer Triangle, appears low in the northeast. These stars remind us that summer is on the way.

Moon Phases

Moon Phases in May 2016:

New: May 6, 2:30 p.m.

First Quarter: May 13, 12:02 p.m.

Full: May 21, 4:14 p.m.

Last Quarter: May 29, 7:12 a.m.

Mercury Transit:

On Monday, May 9, 2016, Mercury overtakes Earth on its much faster orbit. This time, though, when Mercury passes Earth, the alignment is almost exact, such that Mercury appears in silhouette against the sun’s disk. This event is known as a transit of Mercury. Keep in mind that the planets are almost, but not exactly, in the same plane. Indeed, Mercury’s orbit is the most inclined — tilted up to 7 degrees from Earth’s orbital plane. That’s why Mercury does not usually transit the sun when it overtakes Earth. Monday’s event is therefore rare and special, occurring only 14 times in the 21st century (the next one occurs Nov. 11, 2019).

Transit_of_Mercury_May_9_2016_path_across_sun

Thus, weather permitting, the Houston Museum of Natural Science has arranged for volunteers from local astronomy clubs to set up solar telescopes outside our museum’s main entrance, near the sundial, to show you the transit. Mercury, already in the sun’s disk by sunrise in Houston, takes until 1:42 p.m. to cross to the other side of the sun’s disk. If skies cooperate, we’ll observe the transit from 10 a.m. until 1:42 p.m. on Monday, May 9. If there are sunspots on the sun’s disk while Mercury is there, Mercury will stand out because its disk is fully round and because Mercury moves noticeably across the sun’s disk during the hours we’re watching.

We will observe the sun (and Mercury in silhouette) through telescopes with filters especially designed to filter the sun safely, and by projecting the sun’s image onto a screen. These are the only two ways to observe the Sun safely. Please do not try to observe the sun directly or through an unfiltered telescope, as this will lead to permanent eye damage or blindness. Our common sense tells us this because we always avert our eyes when we accidentally turn towards the Sun. When something cool happens on the sun, some of us try to override our common sense, and there is no reason to do so. Come observe safely with us.

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. As of now, George is closed which Brazos Bend State Park dries out from last month’s floods, and is scheduled to reopen May 10. If you’re there, listen for my announcement.