Seeing Stars with James Wooten: Canopus rises in Texas this February

This star map shows the Houston sky at 9 pm CST on February 1, 8 pm CST on February 14, and 7 pm on February 28. To use the map, put the direction you are facing at the bottom. The Great Square of Pegasus sets in the western sky. Taurus, the Bull, is almost overhead. Dazzling Orion, the Hunter is high in the south, with his two dogs behind him. Sirius, the Big Dog Star, is the brightest star we ever see at night. Jupiter, in Gemini, approaches the zenith on February evenings. Look for Canopus, second brightest star ever seen at night, low in the south.

This star map shows the Houston sky at 9 p.m. CST on Feb. 1, 8 p.m. CST on Feb. 14, and 7 p.m. on Feb. 28. To use the map, put the direction you are facing at the bottom. The Great Square of Pegasus sets in the western sky. Taurus, the Bull, is almost overhead. Dazzling Orion, the Hunter is high in the south, with his two dogs behind him. Sirius, the Big Dog Star, is the brightest star we ever see at night. Jupiter, in Gemini, approaches the zenith on February evenings. Look for Canopus, the second brightest star ever seen at night, low in the south.

This month, Venus has entered the morning sky. Look southeast at dawn for the brightest point of light there; only the Sun and Moon outshine Venus. Venus remains a morning star for almost all of 2014.

Jupiter, up literally all night long last month, remains well placed for evening observing all winter and spring. Look for it in the east at dusk and almost overhead later in the evening.

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

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

In February, the Big Dipper only partly risen at dusk. Its two pointer stars — the stars farthest from the handle which point at the North Star —may be high enough to see over trees and buildings.

Watch the Great Square of Pegasus set in the west at dusk. Taurus the Bull is high in the south. Look for the Pleiades star cluster above reddish Aldebaran. Dazzling Orion the Hunter takes center stage on winter evenings. Surrounding Orion are the brilliant stars of winter. Orion’s belt points down to Sirius, the Dog Star, which outshines all other stars we ever see at night. The Little Dog Star, Procyon, rises with Sirius and is level with Orion’s shoulder as they swing towards the south. To the upper left of Orion’s shoulder is Gemini, the Twins, which contains Jupiter this winter.

Under Sirius and low to the southern horizon this month is a star that most Americans never get to see: Canopus. Representing the bottom (keel) of the legendary ship Argo, Canopus is the second brightest star ever visible at night (second to Sirius). Thus, it is clearly noticeable along the southern horizon on February and March evenings. However, you must be south of 37 degrees north for Canopus to rise. (This is the line that divides Utah, Colorado, and Kansas from Arizona, New Mexico, and Oklahoma.)

The sky we see depends on our latitude as well as on the time of night and time of year. From any given location in our hemisphere, there is an area of the sky around the North Star in which stars never set (circumpolar stars), and an equivalent area around the South Celestial Pole in which stars never rise. The closer you are to the pole, the larger these areas are. Observers in Canada, for example, have many circumpolar stars, but there is also a large area of stars that they never see. The closer you get to the equator, the fewer circumpolar stars there are, but there are also fewer stars that never rise for you. At the equator, no stars are either circumpolar or never visible; all of them rise and set as Earth turns.

That’s why, down here in south Texas, the Big Dipper sets, although it’s always up for most Americans. On the other hand, Canopus, too far south to rise for most Americans, rises here.

Moon Phases in February 2014:

1st Quarter: Feb. 6, 1:21 pm
Full: Feb. 14, 5:54 pm
Last Quarter: Feb. 22, 11:16 am
New: Mar. 1, 2:02 am

The Moon takes 27.34 days to orbit Earth; one cycle of Moon phases lasts 29.54 days. At 28 days long, February is the only month shorter than a lunar phase cycle, and thus the only month that can have only three of the four main phases. That’s the case this year, as a New Moon occurred at the end of January and the next comes early on March 1.

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.

Clear skies to you!

Go Stargazing! November Edition

Jupiter is up virtually all night long as November begins.  

Hubble Images Suggest Rogue Asteroid Smacked Jupiter
Creative Commons License photo credit: NASA Goddard Photo and Video

That’s because on Friday night, October 28, Earth passed between the Sun and Jupiter.  In this alignment (‘opposition’) Jupiter rose at dusk and set at dawn.   Face east at dusk and look for the brightest thing there—that’ll be Jupiter.   For the first half of the month, Jupiter does not set until after 5am. 

Venus has begun to emerge from the Sun’s glare.  Look for it low in the southwest in twilight. (Venus is slightly higher in the twilight sky each night this month). This is the beginning of Venus’ apparition as evening star; it gets higher and easier to see for the rest of this year and is spectacular for about the first half of 2012.  For more of a challenge, try to find Mercury under Venus during the first half of the month, as they both set in twilight.

Mars is now high in the east-southeast at dawn.  It now approaches the first magnitude star Regulus in Leo.

Saturn emerges from behind the Sun into the morning sky this month.  Look low in the southeast at dawn, near the star Spica.  (From the Big Dipper’s handle, arc to Arcturus and speed on to Spica).  

The Summer Triangle is high in the west as Sagittarius, the Archer, sets in the southwest.

 As the stars of summer shift to the west, those of autumn fill the sky.   Watch for the Great Square of Pegasus high in the east now and almost overhead at dusk by Thanksgiving.  Pegasus is one of several patterns which depict characters in a single Greek myth (later made into two movies called ‘Clash of the Titans’).  The story begins with Cassiopeia, a queen of Ethiopia who offended the gods by comparing her beauty to that of the Nereids (sea nymphs).  To punish Cassiopeia, the sea god Poseidon sent a giant sea monster, Cetus, to ravage Ethiopian shores.  Cassiopeia’s husband, King Cepheus consulted an oracle and learned that the only way to appease Poseidon was to sacrifice their only daughter, Andromeda, to Cetus.  Andromeda was chained to a rock as everyone waited for Cepheus to come and feed.  However, at just the right moment, the hero Perseus came by.  He had just won great fame by killing Medusa, a woman so hideous that anyone who looked at her turned to stone.  Upon Medusa’s death, the winged horse Pegasus sprang fully formed from her blood, and flew away.  On his way home from that adventure Perseus (flying on winged sandals loaned from Hermes) passed by Ethiopia.  As Cetus rose from the waters to claim his prize, Perseus slew him, saved Andromeda, and married her.  They lived happily ever after. 

Star Cloud Over Saskatchewan.jpg
Creative Commons License photo credit: Space Ritual

In the sky, she is always across the North Star from the Big Dipper. 

In late autumn, as the Big Dipper hugs the horizon and actually sets for us in Houston, Cassiopeia is high in the north, looking like an ‘M’.  In the sky, Cetus swims the very dim region of sky to the south, under Pegasus and Pisces.  Cepheus stands next to his wife in the northern sky, a little to her left as you face north tonight.  Andromeda’s head is Alpheratz, the northeastern star in the Great Square of Pegasus.  From Alpheratz, a curve of stars similar in brightness to Alpheratz and the rest of the Great Square forms her body.  That same curve leads to Perseus in the northeast.
  

Moon Phases in November 2011:
First Quarter November 2, 11:28 am
Full November 10, 2:17 pm
Last Quarter September 20, 8:39 am
Full November 25, 12:10 am

By the way, 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.

Go Stargazing! August Edition

Saturn is the only planet visible to the naked eye at night this August.  Face southwest at dusk and you’ll see Saturn near a star of similar brightness—Spica in Virgo.  Saturn is a bit to the right of Spica as you face southwest.   The ringed planet remains well placed for evening viewing and remains in the night sky until late September 2011.

Hubble Images Suggest Rogue Asteroid Smacked Jupiter
Creative Commons License photo credit: NASA Goddard Photo and Video

Mars and Jupiter are in the pre-dawn sky.  Jupiter, set against a background of very dim stars, dominates the southeastern pre-dawn sky and is due south at dawn by the end of the month.  Mars is dimmer and much lower in the east northeast.  It has fully emerged from the sun’s glare and will brighten slightly each morning. Venus is now out of sight.  Superior conjunction (alignment on the far side of the sun) is on August 16.

The Big Dipper is to the left of 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 and southwest at dusk.  Antares, brightest star of Scorpius, the Scorpion, is in the south, with the ‘teapot’ of Sagittarius to its left.  Meanwhile, the Summer Triangle is approaching the zenith.  The stars of summer now dominate the evening sky.  In late evening, you can watch the Great Square of Pegasus rise in the east.

Moon Phases in August 2011:

1st Quarter                     August 6, 6:08 a.m.

Full Moon                       August 13, 1:57 p.m.

Last Quarter                  August 21, 4:56 a.m.

New Moon                      August 28, 10:03 p.m.

The annual Perseid Meteor Shower peaks this year on Saturday morning, August 13.  Unfortunately, the moon (full on the 13th) hides all but the very brightest meteors and thus spoils the show.  If you want to see just how many Perseids can outshine the moonlight, the best hours are from roughly 2 a.m. to dawn.

Go Stargazing! July Edition

Saturn is the only planet visible to the naked eye in the evening skies of July, 2011.  Face south-southwest at dusk, and you’ll see Saturn near a star of similar brightness—Spica in Virgo.  Saturn is a bit to the right of Spica as you face southwest.   The ringed planet remains well placed for evening viewing, and remains in the evening sky until late September 2011.

Hubble Images Suggest Rogue Asteroid Smacked Jupiter
Creative Commons License photo credit: NASA Goddard Photo and Video

Mars and Jupiter are now higher in the pre-dawn sky.  Jupiter, set against a background of very dim stars, dominates the eastern sky at dawn.  Mars is dimmer and much lower in the east northeast.  It has fully emerged from the sun’s glare, and will brighten slightly each morning.  Venus is now out of sight, as it is passing around the far side of the sun from our perspective.

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 southwest at dusk.  Leo, the Lion, sets in the west at dusk.

Antares, brightest star of Scorpius, the Scorpion, is in the south, with the ‘teapot’ of Sagittarius rising behind it.  The Summer Triangle has fully risen in the northeast.  The stars of summer now dominate the evening sky.

Moon Phases in July 2011:

New Moon                       July 1, 4:02 p.m.

1st Quarter                     July 8, 9:09 p.m.

Full Moon                        July 15, 3:12 p.m.

Last Quarter                  July 23, 6:48 a.m.

Winter Solstice Lunar Eclipse
Creative Commons License photo credit: Bruce McKay~YSP

The new moon of July 1 partially blocks the sun, but only as seen from the Antarctic.  No one will get to see a total eclipse because the moon’s full shadow, or umbra, passes just below the Earth.

As we celebrate our independence this July 4, Earth will be at aphelion (at its greatest distance from the sun).  The precise time is 10 a.m.  Perihelion, the Earth’s closest approach to the sun, occurs in January.  Earth has perihelion and aphelion because its orbit is not a circle but an ellipse with an eccentricity (out-of-roundness) of about 1.6%.  Such a small variation, however, exerts no significant influence on our seasons, as you can determine for yourself by stepping outside.  The 23.5 degree tilt of Earth’s axis, on the other hand, is a much more dominant effect.  The very high midday sun of July ensures long days and baking heat in Houston and across much of the Northern Hemisphere.

By popular demand, our George Observatory will open to the public Fridays and Saturdays this summer (except July 8, due to a prior booking).  The Discovery Dome, our traveling planetarium, will be set up each of these Fridays to show films throughout the evening.