Seeing Stars with James Wooten: Changing stars remind us that summer’s coming

 This star map shows the Houston sky at 10 pm CDT on May 1, 9 pm CDT on May 15, and dusk on May 31.  To use the map, put the direction you are facing at the bottom.  Jupiter sets in the west in Gemini, the Twins. The Big Dipper is as high as it gets in the north. Leo, the Lion, is almost overhead at dusk. From the Big Dipper’s handle, arc to Arcturus and then speed on to Spica in the southeast.  Saturn is below Spica in Libra.  Vega and Antares peek above the horizon, announcing the approaching summer.


This star map shows the Houston sky at 10 p.m. CDT on May 1, 9 p.m. CDT on May 15, and dusk on May 31. To use the map, put the direction you are facing at the bottom. Jupiter sets in the west in Gemini, the Twins. The Big Dipper is as high as it gets in the north. Leo, the Lion, is almost overhead at dusk. From the Big Dipper’s handle, arc to Arcturus and then speed on to Spica in the southeast. Saturn is below Spica in Libra. Vega and Antares peek above the horizon, announcing the approaching summer.

Jupiter remains well placed for evening observing all spring. Look for it in the west at dusk, outshining all the stars we ever see at night. 

Mercury appears in the evening sky this month. Too close to the Sun to observe on May 1, Mercury gradually comes from behind the Sun and by mid-month, it appears low on the western horizon at dusk right above the point of sunset. Greatest elongation (apparent distance from Mercury to the Sun) is on May 25.

Mars is in the southeast at dusk this month. On April 8, Earth passed between the Sun and Mars. Mars has dimmed a little since then as Earth has begun to leave it behind. Still, Mars rivals the brightest stars we see at night.

Saturn is up all night long this month. On May 10, Earth passes between the Sun and Saturn, putting Saturn at opposition. That night, Saturn rises at sundown and sets at sunrise. Thus, Saturn is very low in the southeast at dusk, and very low in the southwest at sunup.

Venus remains in the morning sky. Look east 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.

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 in the east and southeast at dusk. Leo, the Lion, passes almost overhead in late evening.

As Orion and Taurus set, look for Antares, brightest star of Scorpius, the Scorpion, to rise in the southeast. 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 in May 2014:

1st Quarter: May 6, 10:16 pm 
Full May: 14, 2:18 pm
Last Quarter:  May 21, 7:59 am
New May: 28, 1:42 pm 

Click here to see the HMNS 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.

Clear skies!

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!

Party with the planets this Memorial Day: See the closest gathering of any three planets until 2021

As you celebrate this upcoming Memorial Day weekend, take some time to appreciate an interesting sight in the sky — the gathering of Mercury, Venus and Jupiter low in the west-northwest at dusk.

Right now, you notice Jupiter setting in the west at dusk. It outshines all stars we ever see at night, so it’s quite visible even during twilight. Because Earth is about to pass around the far side of the Sun from Jupiter’s position, we see Jupiter get a little lower to the horizon each night this month.

Image courtesy of earthsky.orgImage courtesy of earthsky.org

Perhaps, if your northwest horizon is clear enough, you will also notice Venus below and a bit to the right of Jupiter. In late January 2013, we lost sight of Venus as it began to pass around the far side of the Sun. Now in May 2013, it has begun to come from behind the Sun so that we see it again. Unlike Jupiter, then, Venus gets a little higher in the sky each night. Venus will be an evening star for the rest of 2013.

Mercury is usually invisible to us because it is always in the Sun’s general direction. Only rarely is Mercury far enough from the Sun in our sky to be above the horizon while the Sun is not. June 2013 is one of those exceptional moments. As May 2013 ends, Mercury also enters the evening sky alongside Venus.

On May 23, Mercury is directly beside Venus as both planets are 5 degrees (the width of three fingers, held at arm’s length) to the lower right of Jupiter. By May 26, Mercury and Venus have caught up with Jupiter to form a triangle about two degrees wide. (Jupiter and Mercury are side by side; Venus is the ‘apex’ pointing down.)  On the next night, Memorial Day, we see Venus and Jupiter less then one degree apart, with Mercury about two degrees above them. This will be the closest gathering of any three planets until January 2021.

Keep in mind that to observe any of this, you need a northwest horizon utterly clear of buildings, trees, or other obstacles. You can test your chosen observation site by watching a sunset there. The three planets will appear in the same direction in which the Sun sets. If you can watch sunset all the way until the Sun sets, you’ve picked a good site for observing the May 2013 planet gathering.

Keep in mind that Venus and Jupiter outshine all stars we ever see at night. This means that they become quite visible in twilight. Once you’ve picked a good observation spot, you can begin looking for Venus and Jupiter in twilight (around 8:30 p.m.) without waiting until twilight ends (about 9:15 p.m. at the end of May in Houston).

During June 2013, Mercury and Venus remain in the western sky at dusk, while Jupiter drops into the glare of the Sun. At first, the faster Mercury races out ahead of Venus and is thus higher in the sky. By mid-month, though, Mercury has begun to come around to our side of the Sun, so we see it slow down and head back towards the Sun.  On June 18, Mercury and Venus are side by side once again. Then Mercury drops back into the Sun’s glare, leaving Venus as the planet visible in the west at dusk for the rest of 2013.

Go Stargazing! May Edition

Saturn is the only planet in May 2011 evening skies.  Face south southeast at dusk, and you’ll see Saturn near a star of similar brightness— Spica in Virgo.  Saturn is significantly higher in the sky than Spica and a bit to its right as you face south.  Last month, Earth passed between the Sun and Saturn.  That alignment, called opposition, put Saturn in the sky all night long.  The ringed planet is now well placed for evening viewing, and remains in the evening sky until late September 2011.

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

The other four naked eye planets are involved in a very close gathering low in the east at dawn.  You will need a clear view all the way to the east northeastern horizon at daybreak to observe this planet massing.  However, the planets do outshine all stars in this general area. If you’re able to observe any points of light just above the horizon as dawn begins, you’re probably seeing the planets.  As of now, Venus and Mercury rise first, with Mercury about a degree under the brighter Venus.  Mars and Jupiter are a bit to their lower left, with Mars a little to the left of Jupiter.  Mars was less that half a degree above Jupiter on May 1, and is now slowly pulling away from it.  Venus and Mercury are moving faster, so they are closing the gap on Mars and Jupiter.

On the morning of May 11, Venus and Mercury will be aligned with Jupiter, with Venus less than one degree from Jupiter.  This is also when the entire grouping is the most compact, with all four planets within six degrees of one another.  By May 21, Mercury and Venus will have caught up with Mars, with Venus just over a degree from the red planet.  After this, Mercury and Venus pull ahead of Mars and thus go deeper into the sun’s glare.  Mars and Jupiter, left behind, remain in the morning sky all summer.

Star Gazing
Creative Commons License photo credit: jurvetson

A swath of brilliant winter stars sets in the west at dusk this month.  Orion, the Hunter, is still visible in the west as May begins.  His two dogs, represented by Sirius and Procyon, are to his left.  To Orion’s right is Taurus, the Bull, with the star Aldebaran as its eye. 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 in the east and southeast at dusk.  Leo, the Lion, passes almost overhead in late evening.

As Orion and Taurus set, look for Antares, brightest star of Scorpius, the Scorpion, to rise in the southeast.  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 in May 2011:

New Moon                              May 3, 1:50 a.m.

1st Quarter                             May 10, 3:32 p.m.

Full Moon                               May 17, 6:07 a.m.

Last Quarter                          May 24, 1:51 p.m.