Seeing Stars with James Wooten: April 2013

Published by James on April 2, 2013 at 2:23 pm in Astronomy

Jupiter is now lower in the west at dusk. Face west at dusk and look for the brightest thing there (unless the Moon is also there), as Jupiter outshines all stars we ever see at night.

Saturn shifts from morning to evening sky this month. It rises at about 9:45 p.m. on April 1 and is in the south-southwest by dawn. On April 28, Earth passes between the Sun and Saturn, causing Saturn to rise at dusk and set at dawn. In this alignment, called opposition, Saturn is up literally all night long.

Venus and Mars are still out of sight on the far side of the Sun this month. Mars is behind the Sun (in conjunction with the Sun) on April 17.

Brilliant winter stars shift toward the west during April. Dazzling Orion is in the southwest at dusk. His three-starred belt is halfway between reddish Betelgeuse and bluish Rigel. Orion’s belt points northward to Aldebaran in Taurus the Bull. This winter and spring the Bull also contains Jupiter. To Orion’s upper left are the twin stars Castor and Pollux, marking the heads of Gemini, the Twins. You can find Sirius, the brightest star we ever see at night, by drawing a line from Orion’s belt towards the south. To Orion’s left, forming a triangle with Sirius and Betelgeuse, is Procyon, the Little Dog Star.

Meanwhile, the stars of spring are high in the east and overhead. Look for Leo, the Lion, high in the east at dusk. Also, extend the Big Dipper’s handle to ‘Arc to Arcturus’ and then ‘speed on to Spica’ — these stars are in the east.

Moon Phases in April 2013:

Last Quarter                  April 2, 11:38 pm
New                               April 10, 4:38 am
1st Quarter                    April 18, 7:31 am
Full                              April 25, 2:59 pm

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.

Saturday, April 13, is a special “Observe the Planets” night at the George. Come join us in observing Jupiter and Saturn!

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 2013

Published by James on March 4, 2013 at 3:54 pm in Astronomy

Jupiter is almost overhead at dusk, but now a little toward the west. Face high in the west at dusk and look for the brightest thing there (unless the Moon is also there), as Jupiter outshines all stars we ever see at night.

Saturn remains in the morning sky this month. Look for it in the south/southwest at dawn.

Venus and Mars are on the far side of the Sun and out of sight this month. Venus passes behind the Sun (at superior conjunction) on March 28.

Brilliant winter stars shift toward the southwest during March. Dazzling Orion is almost due south at dusk. His three-starred belt is halfway between reddish Betelgeuse and bluish Rigel. Orion’s belt points up to Aldebaran in Taurus the Bull. This winter and spring the Bull also contains Jupiter.

To Orion’s upper left are the twin stars Castor and Pollux, marking the heads of Gemini, the Twins. You can find Sirius, the brightest star we ever see at night, by drawing a line from Orion’s belt towards the horizon. To Orion’s left, about level with Betelgeuse, is Procyon, the Little Dog Star.

From Sirius, look a little bit to the right and then straight down to the horizon. If your southern horizon is clear of clouds and tall earthly obstacles, you’ll see Canopus, the second-brightest star ever visible at night. This star is so far south that most Americans never see it and many star maps made in the USA omit it. (You must be south of 37 degrees north — the latitude of the USA’s Four Corners — for Canopus to rise). As you view Canopus, keep in mind that the sky we see depends on our latitude as well as on time of year and time of night.

Joining the winter stars are stars of spring rising in the east. Look for Leo, the Lion at dusk. Later in the evening, extend the Big Dipper’s handle to ‘Arc to Arcturus’ and then ‘speed on to Spica’; these stars rise at about 10 p.m. in early March but by 9 p.m. on the 31st.

March 2013 evening skies feature an extra special object — comet Pan-STARRS, our first naked-eye comet since Hale-Bopp back in 1997! Observers south of the equator have already been observing Pan-STARRS, but the comet has been invisible to us because it has been south of the Sun in our sky. That is beginning to change as Pan-STARRS nears its closest approach to the Sun late on March 9.

Like all comets, Pan-STARRS will be at its brightest as it comes closest to the Sun. At the same time, Pan-STARRS will be coming up through the plane where the planets orbit and thus will be much easier for us to see in mid-March. You can start looking in western twilight as early as March 7 if you have a low, unobstructed horizon. The comet may be slightly easier to see on March 12 and 13, when the crescent Moon is nearby. Once Pan-STARRS appears in the western dusk sky, it shifts towards the north (to the right as you face west) each night, until it fades and returns to the Sun’s glare in April.

As always, scientists are unsure how bright Pan-STARRS will get. It now seems that it won’t be as spectacular as was Hale-Bopp in 1997. However, southern observers are seeing it naked-eye, and so should we. The comet could be about as bright as average stars such as those in the Big Dipper, but may be dim enough that you need a dark site to see it, especially once the Moon gets bigger.

Ultimately, though, we’ll have to wait and see. Sky and Telescope has a helpful finder chart here.

Moon Phases in March 2013:
Last Quarter                  March 4, 3:54 pm
New                             March 11, 2:53 pm
1st Quarter                    March 19, 12:26 pm
Full                              March 27, 4:29 am

At 6:01 a.m. on Wednesday, March 20, the Sun is directly overhead at the equator. This therefore is the vernal (spring) equinox, a day when everyone on Earth has the same amount of daylight. After this date, our gradually lengthening days become longer than our nights, and we go into springtime. South of the equator, days have been shortening. For them, this equinox marks the point when night becomes longer than day, and the onset of autumn.

Sunday, March 10, is the second Sunday of this month. Therefore, Daylight Saving Time begins at 2 a.m. this morning (the time officially goes from 1:59 to 3 a.m.) Don’t forget to spring forward by advancing all clocks one hour on Saturday night, March 9!

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. This Spring Break, the George will be open to the public on Tuesday night, March 12, and Thursday night, March 14.

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

Published by James on January 2, 2013 at 3:32 pm in Astronomy

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.

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.

The stars at night are big and bright, deep in . . . New Zealand?

Published by Carolyn S on December 6, 2012 at 11:53 am in Astronomy

Editor’s note: This blog is one of a series of travelogues by HMNS VP of Astronomy Carolyn Sumners, sent from the two-week solar eclipse viewing trip she led to the South Pacific. Astrophotography by Gary Young.

The stars of the southern hemisphere are fantastic, with the brilliant Milky Way stretching from near the hunter, Orion, in the North to Crux, the Southern Cross, in the South.

This predawn image is a time exposure with a Canon Mark II camera and a fisheye lens, taken from our hotel lawn in Queenstown, New Zealand, looking out over Lake Wakatipu. Even with some glare from the hotel and from Queenstown to the East, the predawn sky is remarkably dark. This exposure approximates what we could see as we faced south.

New Zealand has a total population less than 5 million, which guarantees much less light pollution, even close to a city. Also, the southern Milky Way is much richer and more easily seen than the Milky Way near the North Star. In New Zealand, we trade views of the Big and Little Bears for the Southern Cross and the nebulae around it. This image is a close-up of the southern Milky Way in the early evening as we started stargazing. Notice the dark areas in the Milky Way. The Inca saw animals in these dark dust clouds.

While observing through two telescopes, we placed our third telescope, a Takahashi FS60Q, on a small portable Sky Patrol equatorial mount that would track the stars — adjusting for the Earth’s rotation. We were able to do time exposures of up to a minute without guidance and we captured incredible views of the Orion Nebula, the Omega Centauri globular cluster, the Large and Small Magellanic Clouds and the Carina Nebula.

Large and Small Magellanic Clouds

Through a telescope we saw the shapes of these clouds and clusters, but not the rich colors and textures captured in these images. The Orion Nebula is a stellar birth cloud with new stars still forming from the gas and dust. The Carina region has young stars and the dying supergiant Eta Carinae.

Eta Carinae nebula

Omega Centauri is the brightest globular cluster in Earth skies with 5 million stars. The Large and Small Magellanic Clouds are satellite galaxies of our Milky Way galaxy. We can see the Orion Nebula easily from Houston. The other magnificent objects are best seen from below Earth’s equator.

Orion Nebula