Go Stargazing! January Edition

Jupiter, now in the west at dusk, dominates this month’s evening skies.  It outshines all stars in the sky, so it’s easy to find.  Face west southwest at dusk and look for the brightest thing there.

Venus remains a dazzling morning star.  Face southeast at dawn and you can’t miss it.

Saturn is in the south southwest at dawn, above the much brighter Venus.

Mars is still lost in the sun’s glare; it will remain invisible to us all winter as Earth passes around the far side of the sun from it.

The Great Square of Pegasus sets in the west, while brilliant winter stars shine in the south.  Orion, the Hunter, is almost due south.  His two dogs, represented by Sirius and Procyon, are to his left.  Above Orion is Taurus, the Bull with Aldebaran as its eye. Gemini, the Twins, are to Orion’s upper left.

Moon Phases in January 2011:

New Moon                              January 4, 3:03 a.m

1st Quarter                             January 12, 5:32 a.m

Full Moon                               January 19, 3:22 a.m.

Last Quarter                          January 26, 6:58 p.m.

The new moon of Tuesday, January 4, partially blocks the sun, causing a partial solar eclipse.  This event occurs during our nighttime, however; the eclipse is visible only in Europe, western Asia, and northern Africa.

Eclipsed? Not totally.
Creative Commons License photo credit: James Jordan

At about 1 p.m. on Monday, January 3, the Earth is as close to the sun as it will get all year. In other words, Earth is at perihelion. Earth’s orbit is not a perfect circle but an ellipse, so its distance from the sun varies between about 147 million kilometers in January and 152 million kilometers in July. This variation is too small to affect our seasons; the effect of Earth’s 23.5 degree title on its axis dominates it. That’s why it’s colder now than in July. The actual moment of perihelion varies each year between late on January 1 and early on January 5.

At Houston’s latitude, the latest sunrise of the year occurs Friday, January 10.  Of course, days have been lengthening since the solstice, which makes sunset later and sunrise earlier.  However, Earth is still going a little faster than average on its orbit, since it is just past perihelion (its closest approach to the sun).  This causes sunrise, local noon, and sunset to occur slightly later each day.  Until mid-January, we are still close enough to perihelion that the second effect actually predominates.  As a result, sunset gets a little later during early January even while the days are getting longer.

Astronomy Day 2010

Todays blog post is from Cynthia Gustava, who is planning the events surrounding Astronomy Day 2010. Come down to the George Observatory this Saturday and learn all about astronomy and our amazing facility in Brazos Bend State Park

The George Observatory, a satellite facility of the Houston Museum of Natural Science, will again host its annual Astronomy Day activities. The event is this Saturday, Oct. 16, 2010.  We’ll officially open the doors to the public at 3 p.m., and events will begin to wind down at around 10:30 p.m.

Before opening the doors to the public at 3 p.m., we will be heading up a telephone contact with the International Space Station (ISS), which will be broadcast and recorded. The pass of the ISS is (at this writing) expected to be some time around 11:30 a.m. One scout troop and one school group coming in for an early Challenger Center mission will participate in this contact and ask questions of the ISS crew. We are encouraging all volunteers to be up on deck to listen to this special event, which will take approximately 10 minutes.

The observatory is home to three high-quality telescopes, including the multi-million dollar, 36-inch diameter Gueymard telescope, which is used regularly for scientific research. The 11-inch refractor mounted on one side of the Gueymard telescope was donated to the George Observatory by Preston and Donna Engebretson of Houston and has proven to be a wonderful addition to the retinue of telescopes housed in the domes. The 11” refractor telescope provides impressive views of planets and deep sky objects alike.

The astronomy clubs from Houston and Beaumont come together this one day of the year for the purpose of sharing with the general public as much information about astronomy as possible in one day. Local area amateur astronomers are part of the lecture agenda taking place indoors with talks starting at 4 p.m., and running every hour until 10 p.m. There are also outdoor presentations by amateur astronomers every half hour until dark, learning tools for the young and old, kid’s activities, face painting, button making, night sky constellation tours and the opportunity to impart your knowledge of night sky objects to the public. Tables will be set up in the downstairs lobby and foyer by HCC Southwest Campus, the Night Sky Network, Land Sea & Sky, Advanced Telescope Repair and the usual Astronomy “club” table. Be sure to visit the new NASA pop-up displays set up downstairs in the main area. These will display images and information on the ISS and the Hubble Space Telescope. The theme this year for the astronomy t-shirts, and for the entire event, will commemorate the 20th birthday of the Hubble telescope. 

Consider bringing your solar-filtered telescope to set up on the deck in the afternoon hours to provide safe viewing of the Sun. Also in the afternoon, a simulated spaceship flight to the Moon in the Challenger Center will be open to the public.

If you are new to the area, the George Observatory, located within Brazos Bend State Park, is about one hours’ drive southwest of Houston. The Brazos Bend State Park is a fascinating blend of lakes and trails, with alligators, small animals and wild birds of many types. The Park and the George Observatory can be reached in two ways. Maps and driving directions are available here.

We hope you can join us for a day of astronomy and fun!

Cynthia Gustava
Astronomy Day Coordinator


Go Stargazing! December Edition

The ‘main event’ of December evenings occurs in the southwest at dusk, where you can watch Venus pull away from Jupiter.  Look southwest right as night falls for the two brightest things there except for the Moon.  The brighter one low in the southwest is Venus, which outshines everything else in the night sky.  Jupiter is the dimmer of the two, although it still outshines all the stars we ever see at night.  Venus and Jupiter begin the month about 2 degrees apart (your finger at arms length blocks about 1 degree.)  However, Venus will extend that gap quite noticeably each night, until it appears high above Jupiter on December 31. 

Mercury emerges from the Sun’s glare in time to form a nice pair with Jupiter on New Year’s Eve.  As you prepare to ring in 2009, take a moment to look at Mercury just to Jupiter’s left in late twilight.  That same night, the Moon will be near Venus. Saturn can be found high in the south at dawn.  Mars is lost in the Sun’s glare this month, and will remain out of sight into 2009.  It is directly behind the Sun (in conjunction with the Sun) on December 5.

Orion no céu
Creative Commons License photo credit: giumaiolini

The enormous Summer Triangle, consisting of the stars Deneb, Vega, and Altair, sets in the west.  The Great Square of Pegasus is overhead at dusk.  The star in its upper left hand corner is also the head of Andromeda.  Facing north, you’ll see five stars in a distinct ‘M’ like shape—this is Cassiopeia, the Queen.  Her stars are about as bright as those in the Big Dipper, and she is directly across the North Star from the Dipper.  In fall and early winter, while the Dipper is low and out of sight, Cassiopeia rides high.

Dazzling Orion rises in the east, reminding us that winter is on the way.  His belt points up to Aldebaran, the eye of Taurus the Bull.  By 9 pm tonight (7 pm by New Year’s Eve), the Dog Stars Sirius and Procyon will have risen below Orion in the east.  Sirius is the brightest star we ever see at night. 

Moon Phases in December 2008:

1st Quarter         December 5, 3:25 pm
Full                     December 12, 10:38 am
Last Quarter        December 19, 4:30 am
New                    December 27, 6:22 am

At 6:04 am on Sunday, December 21, the Sun is directly overhead at the Tropic of Capricorn, meaning that the North Pole is tilted as much as possible away from the Sun.  This is the winter solstice.  For people in the Northern Hemisphere, December 21 has less daylight and more night than any other day of the year. 

Sunset at Appalachian Trail
Creative Commons License photo credit: Pardesi*

However, the earliest sunsets occur on December 1 and 2.  We are already close enough to the solstice that the Sun’s apparent path across the sky on December 21 is only slightly lower than on any other day this month.  Meanwhile, Earth is about to make its nearest approach to the Sun, called perihelion, in January.  As a result, the Earth is speeding up.  The effect isn’t much (Earth’s orbit is nearly circular), but it’s enough to make both sunrise and sunset a little later each day this month and next.  With the Sun’s apparent height in the sky not changing that much in December and January, the small effect of Earth’s acceleration near perihelion dominates.  Since most of us sleep through sunrise and witness sunset, the days seem be slightly lengthening between the beginning of the month and the 21st, although they are actually getting slightly shorter.

Go Stargazing! November Edition

mars-06-crop
Creative Commons License photo credit: chipdatajeffb

The “main event” of November evenings occurs in the southwest at dusk, where you can watch Venus close in on Jupiter.  Look towards the southwest right as night falls for the two brightest objects in the sky, other than the Moon.  The brighter one low in the southwest is Venus, which outshines everything in the sky except the Sun and the Moon.  Jupiter is closer to due south at dusk and is the dimmer of the two, although it still outshines all the stars we see at night. 

Venus and Jupiter begin the month just under 30 degrees apart (your fist at arms length blocks about 10 degrees).  However, Venus will close that gap quite noticeably each night, until it appears directly under Jupiter on November 30.  The two planets will then be about 2 degrees apart.  When two or more planets are roughly in the same line of sight, astronomers say they are in conjunction. Saturnis still visible at this time of year, it resides high in the east and can be seen around dawn.  Mars is lost in the Sun’s glare this month, and will remain out of sight into 2009. 

Look for the enormous Summer Triangle, consisting of the stars Deneb, Vega and Altair, high in the west.  The Great Square of Pegasus is high in the east at dusk.  The star in its upper left hand corner is also the head of Andromeda.  Facing north, you’ll see five stars in a distinct ‘M’ like shape—this is Cassiopeia, the Queen.  Her stars are about as bright as those in the Big Dipper, and she is directly across the North Star from that Dipper.  In fall, while the Dipper is low and out of sight, Cassiopeia rides high.

Our Milky Way Galaxy..
Creative Commons License photo credit:
Sir Mervs (byaheng bicol)

You’ll notice that November skies at dusk, especially to the south and east, contain many fewer bright stars than skies of summer or winter.  This is because we are facing out of the galaxy plane when we look in that direction.  The Summer Triangle and Cassiopeia are in the galaxy plane, where most bright stars are.  Looking away from that, we see a large are of dim stars known to the ancients as the ‘Celestial Sea’.  By late evening (10 pm now, 8 pm by the 30th), dazzling Orion rises in the east, reminding us that winter is on the way.


Moon Phases in November 2008:

1st Quarter          November 5, 10:03 am
Full                      November 13, 12:18 pm
Last Quarter         November 19, 3:32 am
New                     November 27, 10:55 pm

Love Astronomy? Check these out:
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