Seeing Stars with James Wooten: Venus shifts to morning, Chinese New Year approaches

This star map shows the Houston sky at 90 pm CST on January 1, 8 pm CST on January 15, and 7 pm on January 31.  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 southeast, with his two dogs behind him.  Sirius, the Big Dog Star, is the brightest star we ever see at night.  Jupiter, in Gemini, is up all night long in early January.  In the north, the Big Dipper gradually re-enters the evening sky.

This star map shows the Houston sky at 90 pm CST on January 1, 8 pm CST on January 15, and 7 pm on January 31. 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 southeast, with his two dogs behind him. Sirius, the Big Dog Star, is the brightest star we ever see at night. Jupiter, in Gemini, is up all night long in early January. In the north, the Big Dipper gradually re-enters the evening sky.

This month, Venus shifts from the evening to the morning sky. For the next few days, look for it low in the southwest at dusk. If no buildings or trees block the view, you can still make out Venus in the twilight; it outshines everything in the sky but the Sun and the Moon. Notice how it appears lower on the horizon each night and is soon completely gone.

On Jan. 10, Venus passes between Earth and Sun (“inferior conjunction“), which would normally make it invisible to us. This time, however, Venus passes above the Sun from our perspective, which means the sharp-eyed observers with clear horizons can observe Venus both at dawn and at twilight for a few days around Jan. 10. After this, you can watch Venus emerge in the morning sky, visible in the southeast at dawn.

Venus remains a morning star for almost all of 2014.

Mercury briefly enters the evening sky this month, right as Venus leaves. Look for it low on the horizon during the last half of January. Although not nearly as bright as Venus, it easily outshines the dim stars near it. Thus, any “star” you see in twilight over the point of sunset late this month is probably Mercury.

Jupiter will remain well placed for evening observing all winter and into the spring (as the Earth passed between it and the Sun on Jan. 5). 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 southwest at dawn.

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

In January, the Big Dipper is only partly risen at dusk. As the Big Dipper sets, though, Cassiopeia rises. This is a pattern of five stars in a distinct W (or M) shape which lies directly across the North Star from the Big Dipper. Look for Cassiopeia high in the north on fall and winter evenings.

Watch for the Great Square of Pegasus 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.


Moon Phases in January 2014:

New: Jan. 1, 5:15 a.m.; Jan. 30, 3:40 p.m.
1st Quarter: Jan. 7, 9:40 p.m.
Full: Jan. 15, 10:53 p.m.
Last Quarter: Jan. 23, 11:21 p.m.

At 5:59 a.m. on Sat., Jan. 4, the Earth is as close to the Sun as it will get this year; this is called perihelion. Keep in mind that Earth’s orbit is so close to being a perfect circle that its perihelion distance is 0.98 AU, where 1 AU (astronomical unit) is defined as the average Earth-Sun distance. This 2% difference is too small to influence our seasons; the tilt of the Earth’s axis toward or away from the Sun dominates this small effect. That’s why it’s so cold right now (even here in Houston!) and so hot in July.

Although the winter solstice is the shortest day, the earliest sunset occurred on about December 2, and the latest sunrise will occur January 10. That’s because the Earth speeds up on its orbit near perihelion. This acceleration shifts sunrise, local noon, and sunset slightly later each day at this time of year. The effect is smaller than that of the Sun taking a low 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 being nearer to the Sun to predominate.

For most people, then, (those who witness sunset but sleep through sunrise), days will seem to lengthen much more than they actually are. Early risers, on the other hand, will find sunrise occurs even later than last month, at least until late January.

The New Moon of Jan. 30 is the second New Moon after the winter solstice. It therefore marks Chinese New Year. On this date, the Year of the Snake ends and the Year of the Horse begins.

Visit the HMNS website to see this month’s 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. We’re also hosting telescope classes on Jan. 11, so if you or someone you know received one over the holidays come by and let us help you set it up!

Seeing Stars with James Wooten: July 2013

Venus remains in the west at dusk. It outshines everything but the Sun and Moon, so you can begin observing it during deep twilight.

Saturn is now shining in the south/southwest at dusk. Although not as bright as Venus, it does outshine the stars around it, so you can’t miss it.

Mars and Jupiter emerge into the morning sky this month. Look for them low in the east/northeast at dawn, with Jupiter much brighter. Mars passes less than one degree from Jupiter on the morning of July 22.

Sky Map July 2013

The Big Dipper is above the North Star and to its left, 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, sets in the west at dusk.

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

Moon Phases in July 2013:

New                               July 8, 2:15 a.m.
First Quarter                 July 15, 10:19 p.m.
Full                                July 22, 1:15 p.m.
Last Quarter                 July 29, 12:44 p.m.

At about 10 a.m. on Friday, July 5, the Earth is as far from the Sun as it will get this year — a position known as aphelion. It may seem counterintuitive to be farthest from the Sun now and closest to the Sun just after the New Year, however, the Earth’s orbit is almost a circle; the difference between perihelion and aphelion is too small to affect our seasons.

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. I generally do one such tour on short May nights.

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: 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.

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.