Seeing Stars with James Wooten: Mars and the Moon share the limelight

This star map shows the Houston sky at 10 pm CDT on April 1, 9 pm CDT on April 15, and dusk on April 30.  To use the map, put the direction you are facing at the bottom.  Jupiter is high in the west in Gemini, the Twins. Below them, Dazzling Orion, the Hunter sets with Taurus, the Bull.  To Orion’s left are the two Dog Stars—little dog Procyon and big dog Sirius.  Sirius outshines all other stars we see at night.  The Big Dipper is high in the north. Leo, the Lion, is high in the south. These stars, along with Arcturus, announce the spring.  Mars is up all night long this month.

This star map shows the Houston sky at 10 p.m. CDT on April 1, 9 p.m. CDT on April 15, and dusk on April 30. To use the map, put the direction you are facing at the bottom. Jupiter is high in the west in Gemini the Twins. Below them, Dazzling Orion the Hunter sits with Taurus the Bull. To Orion’s left are the two Dog Stars: little dog Procyon and big dog Sirius. Sirius outshines all other stars we see at night. The Big Dipper is high in the north. Leo the Lion, is high in the south. These stars, along with Arcturus, announce the spring. Mars is up all night long this month.

This month, Jupiter remains well placed for evening observing all spring. Look for it high in the west at dusk.

Mars is up virtually all night long this month. On April 8, Earth passes between the Sun and Mars. This places Mars at opposition, an alignment where we see Mars rise at dusk and set at dawn — Mars is up literally all night long. It turns out that Mars is farther from the Sun than average when Earth passes it, so at this opposition Mars is not as big or bright as in years past. Still, Mars now rivals the brightest star at night, Sirius, and is now as bright as it will get until May 2016.

Saturn remains in the pre-dawn sky. Face south right before sunup to see it. You can also begin observing Saturn in late evening. It rises just after 10:30 p.m. tonight, and then about a half hour earlier each night until by month’s end, it’s up until twilight. Saturn comes to opposition next month.

Venus remains in 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.

Brilliant winter stars shift towards the west during April. Dazzling Orion is high in the southwest at dusk. His three-starred belt is halfway between reddish Betelgeuse and bluish Rigel. Orion’s belt points right to Aldebaran in Taurus the Bull. Above Orion are the twin stars Castor and Pollux, marking the heads of Gemini the Twins. Jupiter is among the Twins this month. You can find Sirius, the brightest star we ever see at night, by drawing a line south from Orion’s belt (left as you face west). Forming a triangle with Betelgeuse and Sirius is Procyon the Little Dog Star.

Joining the winter stars are stars of spring in the south and east. Look for Leo the Lion almost overhead at dusk. In the east, extend the Big Dipper’s handle to “arc to Arcturus” and then “speed on to Spica.”

Moon Phases in April 2014:

1st Quarter: April 7, 3:31 a.m.
Full: April 15, 2:44 a.m.
Last Quarter: April 22, 2:52 a.m.
New: April 29, 1:17 a.m.

The Full Moon of Tuesday morning, April 15, fully enters the Moon’s shadow, causing a total eclipse of the Moon. The Moon first encounters the shadow at 12:58 a.m.; that’s when the partial phases begin. By 2:06 a.m., the Moon is all the way inside the shadow, and thus totally eclipsed. The Moon takes 78 minutes to cross the shadow, so totality lasts until 3:24 a.m.. The Moon then emerges from the Earth’s shadow until the eclipse is over at 4:33 a.m.

Keep in mind that the eclipse happens in the morning hours of Tues., April 15. Don’t go out looking for this Tuesday night! Our George Observatory will be open from sundown Mon., April 14 until dawn on Tues., April 15 for observing the eclipse. If you can’t come to the George at such early morning hours, remember that anyone who sees the Moon sees the eclipse. You can observe this eclipse from your backyard or even through your window if you have one that faces south/southwest.

The only thing that can stop you from seeing the eclipse is overcast weather. If we do get clouded out, or if you can’t get up in the middle of the night, we can observe another eclipse on Oct. 8, 2014, right before dawn.

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: 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!

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.