Seeing Stars with James Wooten: January 2013

Happy New Year! This January, Mars continues to fade as it drops into the Sun’s glare. 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 Jan. 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.

Venus is lower in the east at dawn than before. You can still observe it this month and next.

Saturn is a little higher in the morning sky this month. Look for it just in the south at dawn.

Sky Map: January 2013

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. Jupiter, outshining all stars in the night sky, is in Taurus between Aldebaran and the Pleiades. In the north, the Big Dipper has been out of sight under the North Star for a while. In January, though, you can look for the two pointer stars, which point at the North Star, peeking over trees and houses to the north/northeast.

Moon Phases in January 2013:
Last Quarter                  January 4, 9:58 p.m.
New                               January 11, 1:44 p.m.
1st Quarter                    January 18, 5:45 p.m.
Full                                January 26, 10:39 p.m.

At 11 p.m. on Tuesday, Jan. 1, the Earth passed as close to the Sun as it will get this year. Thus, Earth is now just past perihelion. If we’re closer to the Sun now, why is it cooler (even in Houston)? Notice how low the midday Sun is right about now. Six months from now, take note of how high the Sun is in June and July. That’s what makes it so much cooler now and so hot then.

The Earth’s orbit is, in fact, almost perfectly circular; there is only a 3-percent difference between perihelion and aphelion distance. The 23.44-degree tilt of the Earth makes the Sun appear high if we tilt towards it and low if we tilt away, and dominates the small effect of Earth’s changing distance.

The latest sunrise of the year (at Houston’s latitude) occurs on Jan. 10. Earth, just past perihelion, has sped up a little in its orbit since it is a little closer to the Sun. As a result, sunrise, local noon, and sunset have been happening a little later each day since early December. The noon Sun is ever so slightly higher at noon each day since the solstice (Dec. 21), but as of today, the Sun is still very close to its solstice height. Beginning Jan. 11, the noon Sun’s greater height in the sky again becomes the dominant effect (as it is for most of the year). From then until June, sunsets are getting later while sunrises are getting earlier.

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.

Seeing Stars with James Wooten: April 2012

April 2012 features four visible planets, visible at convenient evening hours!

Venus continues to appear high in the sky each night, outshining everything but the Sun and the Moon. Look for it in the west at dusk.

seeing stars april

This is the last month to see Jupiter in evening hours for some time. On the first few nights of April, Jupiter is low in the west — far below Venus. However, Jupiter appears slightly lower in the sky each night until it is lost in the Sun’s glare by month’s end. It outshines all stars we ever see at night, however, so it’s still not hard to find.

Mars has joined Jupiter and Venus as an evening object. Face east at dusk and look for the brightest point of light in that direction. Although not as bright as Venus or Jupiter, Mars still rivals the brightest stars in the night sky. However, Mars fades a little bit each night as Earth pulls away from it (on March 3, Earth passed between Mars and the Sun).

Saturn becomes an evening object this month. On April 15, Earth aligns with the Sun and Saturn, placing Saturn at opposition — just as Mars was last month.

Brilliant winter stars continue to dominate the western sky at dusk.  Orion, the Hunter, is almost due south. His two dogs, represented by Sirius and Procyon, are to his left.  To Orion’s right is Taurus, the Bull, with Aldebaran as its eye. Gemini, the Twins, are above Orion. Leo, the Lion, is approaching the zenith. In the east, you can use the Big Dipper’s handle to find two bright stars of spring. From the Big Dipper’s handle, arc to Arcturus and speed on to Spica.

Moon Phases in April 2012:

Full                            April 6, 2:19 p.m.

Last Quarter       April 13, 5:50 a.m.

New                           April 21, 2:19 a.m.

1st Quarter           April 29, 4:57 a.m.

Sunday, April 8 is the first Sunday after the first full moon following the first day of spring. Therefore, it’s Easter Sunday.

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.

Seeing Stars with James Wooten: March 2012

March 2012 features all five visible planets, visible at convenient evening hours!

Astronomy Day 2008

Venus continues to appear higher and higher in the sky each night, outshining everything but the Sun and the Moon.  Look for it in the west at dusk.  It is also still approaching Jupiter each night as March begins.  On the first few nights of March, Venus is just over 10 degrees below Jupiter in the west.  However, Venus continues to close that gap until March 13, Venus and Jupiter are side by side, with Venus on the right.  After that, Venus pulls away, appearing higher than Jupiter in the west at dusk.  Jupiter outshines everything in our sky except the Sun, the Moon, and Venus.  Venus and Jupiter thus make a spectacular pair in the west this month.

Mars has joined Jupiter and Venus as an evening object.  Face east at dusk and look for the brightest point of light in that direction.  Although not as bright as Venus or Jupiter, Mars has brightened enough to rival Sirius, the brightest star we ever see at night. On March 3, Earth passes between Mars and the Sun, putting Mars in our sky literally all night long (an alignment called opposition).

Mercury is ordinarily too close to the Sun to observe; only rarely is it far enough from the Sun to be still up after sundown.  Early March 2012 is one of those rare times, however.  During the first two weeks of March, look for Mercury low in the west at dusk, between Venus and the point of sunset.  Mercury is highest in the sky on March 5 and gets a little harder to see each day after that.

Saturn becomes a late evening object this month.  Look in the south southeast beginning at about 10:00 pm on March 1, and by 8:40 (just after twilight ends) on March 31.  Saturn is near the star Spica.  (From the Big Dipper’s handle, arc to Arcturus and speed on to Spica).

Big Dipper in a big sky

Brilliant winter stars continue to dominate the southern sky at dusk.  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.  Leo, the Lion, is rising in the east.

Below Sirius, just above the southern horizon, is a star second only to Sirius in brightness.  This is Canopus, which marks the keel (bottom) of the legendary ship Argo Navis.  Canopus is so far south, in fact, that most Americans never see it.  From the Gulf Coast, however, Canopus does rise.  February and March are the best months to see it at dusk.

Moon Phases in March 2012:

Full                               March 8, 3:41 am

Last Quarter                  March 14, 8:26 pm

New                              March 22, 9:38 am

1st Quarter                     March 30, 2:41 pm

At 12:13 am on Tuesday, March 20, the Sun is directly overhead at the equator.  This, then, is the vernal (spring) equinox, marking the official beginning of spring in the Northern Hemisphere.  In the Southern Hemisphere, summer turns to fall.

Visit www.hmns.org for the latest planetarium schedule.

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! December Edition

Jupiter is well placed for observing on December evenings. Face east at dusk and look for the brightest thing there—that’ll be Jupiter.

Venus has fully emerged from the Sun’s glare.

After Sunset (Moon & Venus & Jupiter)
Creative Commons License photo credit: scyllarides

Look for it low in the southwest at dusk. (Venus is slightly higher in the evening sky each night this month). We are still near 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.

Mars rises around midnight and is now high in the south at dawn. Although not nearly as bright as Venus or Jupiter, Mars has brightened enough to rival the brightest stars in the sky, and will keep brightening all winter as Earth approaches it.

Saturn remains in 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 sets in the west. Watch for the Great Square of Pegasus almost overhead at dusk now and in the west by Christmas. 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 late autumn, as the Big Dipper hugs the horizon and actually sets for us in Houston, Cassiopeia is high in the north. 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.

Orion nebula: M42
Creative Commons License photo credit: Alessandro S. Alba

Moon Phases in December 2011:
First Quarter December 2, 3:52 am
Full December 10, 8:37 am
Last Quarter December 17, 6:48 pm
New December 24, 12:07 pm

The Full Moon of Saturday morning, December 10, enters the Earth’s shadow, causing a total lunar eclipse.

Unlike last year’s event, however, this eclipse heavily favors western observers in North America; we miss most of it here in Houston. However, the Moon does nick the edge of Earth’s umbra at 6:46 am that morning, when it is a scant three degrees above our horizon in Houston. If you have a northwest horizon utterly clear of trees or buildings, you might try to observe the very beginning of the eclipse before moonset.

At 11:30 pm on Wednesday, December 21, the Sun is directly overhead as seen from the Tropic of Capricorn, the farthest point south where this is possible. That makes December 21 the winter solstice, the date when the noon Sun is lowest in the sky, and when we have the fewest daylight hours of the year. However, the earliest sunset of the year here in Houston is not on the solstice, but approximately on December 2! 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 that 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 December 21.

We are making improvements to the main telescope at George Observatory! Visitors on Saturday, December 10 and December 17 will find the 36-inch Gueymard telescope closed for repairs. Our 14-inch east dome telescope and 18-inch west dome telescope will still be open to the public, however, so we hope you’ll join us anyway! Also, Christmas Eve and New Year’s Eve fall on Saturday this year; the observatory will be closed on December 24 and 31.

Visit www.hmns.org to see the Planetarium’s film Schedule.

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.