Seeing Stars with James Wooten: Exciting Rare Mercury Transit Next Monday!

May Starmap

Jupiter is now high in the south at dusk. It outshines all stars we ever see at night, so you can’t miss it.

Mars and Saturn become late evening objects this month. Tonight, May 2, Mars rises in the southeast at 9:48 p.m. while Saturn comes up soon afterwards, at 10:24 p.m. By May 15, though, both planets rise during twilight, and on Memorial Day both are in the southeastern sky as soon as it gets dark. Mars and Saturn are still above the distinctive pattern of Scorpius, the scorpion. As you watch them rise, Mars is to the upper right and is much brighter.

In fact, this month, Mars outshines all of the stars and even rivals Jupiter in brightness! That’s because on May 22, Earth passes between the Sun and Mars. That alignment is called ‘opposition’ because it puts Mars opposite the Sun in our sky, making Mars visible literally all night long. It also makes Mars much brighter than normal in the sky, since we’re as close to it as we’ll ever get until Earth overtakes Mars again in 2018. Saturn comes to opposition June 3.

Venus is lost in the Sun’s glare and out of sight all month.

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 high in the east and in the south, respectively, at dusk. Leo, the Lion, passes almost overhead at dusk.

As Orion and his dogs set, look for Antares, the brightest star in Scorpius, the Scorpion, to rise in the southeast. Saturn and Mars will rise with the Scorpion’s head, above Antares. 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

Moon Phases in May 2016:

New: May 6, 2:30 p.m.

First Quarter: May 13, 12:02 p.m.

Full: May 21, 4:14 p.m.

Last Quarter: May 29, 7:12 a.m.

Mercury Transit:

On Monday, May 9, 2016, Mercury overtakes Earth on its much faster orbit. This time, though, when Mercury passes Earth, the alignment is almost exact, such that Mercury appears in silhouette against the sun’s disk. This event is known as a transit of Mercury. Keep in mind that the planets are almost, but not exactly, in the same plane. Indeed, Mercury’s orbit is the most inclined — tilted up to 7 degrees from Earth’s orbital plane. That’s why Mercury does not usually transit the sun when it overtakes Earth. Monday’s event is therefore rare and special, occurring only 14 times in the 21st century (the next one occurs Nov. 11, 2019).

Transit_of_Mercury_May_9_2016_path_across_sun

Thus, weather permitting, the Houston Museum of Natural Science has arranged for volunteers from local astronomy clubs to set up solar telescopes outside our museum’s main entrance, near the sundial, to show you the transit. Mercury, already in the sun’s disk by sunrise in Houston, takes until 1:42 p.m. to cross to the other side of the sun’s disk. If skies cooperate, we’ll observe the transit from 10 a.m. until 1:42 p.m. on Monday, May 9. If there are sunspots on the sun’s disk while Mercury is there, Mercury will stand out because its disk is fully round and because Mercury moves noticeably across the sun’s disk during the hours we’re watching.

We will observe the sun (and Mercury in silhouette) through telescopes with filters especially designed to filter the sun safely, and by projecting the sun’s image onto a screen. These are the only two ways to observe the Sun safely. Please do not try to observe the sun directly or through an unfiltered telescope, as this will lead to permanent eye damage or blindness. Our common sense tells us this because we always avert our eyes when we accidentally turn towards the Sun. When something cool happens on the sun, some of us try to override our common sense, and there is no reason to do so. Come observe safely with us.

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. As of now, George is closed which Brazos Bend State Park dries out from last month’s floods, and is scheduled to reopen May 10. If you’re there, listen for my announcement. 

Seeing Stars with James Wooten: Last Chance for Winter Constellations in April

Starmap April

Jupiter is now high in the east-southeast at dusk. It outshines all stars we ever see at night, so you can’t miss it. 

Mercury is visible just after sunset this month. Face west at twilight, and look low in the sky over the point where the sun sets. Mercury isn’t as brilliant as Venus or Jupiter, but it easily outshines the stars near it in the sky, so it’s not too hard to find. 

Mars is in the south-southwest at dawn. Noticeably reddish in tint, Mars continues to brighten each day until its opposition in May. It has now surpassed nearby Saturn in brightness.

Saturn is in the south-southwest at dawn, above the distinctive pattern of Scorpius, the scorpion. Mars remains close to Saturn this month.

Venus is becoming lost in the sun’s glare. Already, it doesn’t rise until deep into morning twilight, and Venus continues to approach the sun all month.

April is the last month to see the set of brilliant winter stars which now fill the western evening sky. Dazzling Orion is in the southwest at dusk. His three-starred belt is halfway between reddish Betelgeuse and bluish Rigel. Orion’s belt points rightward to Aldebaran in Taurus the Bull. 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 left. Forming a triangle with Sirius and Betelgeuse is Procyon, the Little Dog Star. 

Joining the winter stars are stars of spring rising in the east. Look for Leo, the Lion at dusk. Ursa Major, the Great Bear, which includes the Big Dipper, is high above the North Star on spring evenings. Extend the Big Dipper’s handle to ‘Arc to Arcturus’ and then ‘speed on to Spica’. There are fewer bright stars in this direction because of where the plane of our galaxy is in the sky. The area of sky between Gemini and Taurus and over Orion’s head is the galactic anticenter, which means that we face directly away from the galactic center when we look in this direction. Those bright winter stars setting in the west are the stars in our galactic arm, right behind the sun. On the other hand, if you look at the sky between Ursa Major, Leo, Virgo, and Bootes, you’re looking straight up out of the galactic plane, towards the galactic pole. There are fewer stars in this direction.

Moon Phases

Moon Phases in April 2016:

New: April 7, 6:24 a.m.

First Quarter: April 13, 10:59 p.m.

Full: April 22, 12:24 a.m.

Last Quarter: April 29 10:29 p.m.

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: Winter Stars Shift to the Southwest

This star map shows the Houston sky at 9 pm CST on March 1, 9 pm CST on March 15, and dusk on March 31.  To use the map, put the direction you are facing at the bottom.

This star map shows the Houston sky at 9 pm CST on March 1, 9 pm CST on March 15, and dusk on March 31. To use the map, put the direction you are facing at the bottom.

Jupiter comes to opposition on March 8, which is when Earth aligns with Jupiter and the Sun. That is why Jupiter is up all night long in early March. Face east in evening twilight to watch Jupiter rise. It outshines all stars we ever see at night, so you can’t miss it. Early risers will still see Jupiter setting in the west at dawn.

Venus is in the southeast at dawn, appearing lower to the horizon each morning this spring. Venus outshines all the stars we see at night, and in fact outshines everything but the Sun and the Moon. However, now it doesn’t rise until morning twilight, and will soon become lost in the Sun’s glare. How long can you follow it?

Mars is in the south at dawn. Noticeably reddish in tint, Mars continues to brighten each day until its opposition in May; it has now surpassed nearby Saturn in brightness.

Saturn is in the south at dawn, above the distinctive pattern of Scorpius, the scorpion. Mars slowly approaches Saturn this month.


Brilliant winter stars shift towards 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. 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 10:00 in early March but by 9pm on the 31st.

Moon Phases

Moon Phases in March 2016:

Last Quarter Mar. 1, 5:11 p.m.; Mar. 31, 10:17 a.m.

New Mar. 8, 7:54 p.m.

1st Quarter Mar. 15, 12:03 p.m.

Full Mar. 23, 7:01 a.m.

The New Moon of March 8 actually blocks the Sun, causing an eclipse of the Sun! However, it is visible only in Indonesia and the Pacific, where it will be March 9.

The Full Moon of March 23 passes though the penumbra, in which Earth partially blocks the Sun, but misses the true shadow or umbra. The resulting penumbral eclipse is only barely noticeable.

Sunday, March 13, is the second Sunday of the month. Accordingly, Daylight Saving Time begins at 2:00 am on that date. (Officially, the time goes from 1:59 to 3:00 am). Don’t forget to spring forward!

At 11:30 pm on Saturday, March 19, the Sun is directly overhead at the equator, shifting northward. That makes this the vernal (spring) equinox for us. Beginning on this date, day is longer than night for us in the Northern Hemisphere. Meanwhile, below the equator, days are shortening and now day is shorter than night. It is autumn down there.

On Friday, March 11, the brand new Burke Baker Planetarium re-opens to the public. Over Spring Break, come join us and enjoy images sharper than in any other theater!

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!

James G. Wooten
Planetarium Astronomer
Houston Museum of Natural Science

The cutting-edge returns to the Burke Baker Planetarium, where astronauts once trained

Think back to the technology of the late 1980s: corded phones, boom boxes, cathode color TVs. In this era, it’s tough to imagine how anyone achieved the remarkable feat of traveling to space and orbiting the Earth without WiFi or contemporary computers. But Americans did it, and we made history!

Alan Shepard

Alan Shepard was the second person and first American to travel into space. He reached a height of 116 statute miles in 1961.

Now imagine what it must have been like being in space, orbiting the Earth fast enough to circle all of humanity in 90 minutes. It’s cold, it’s dark, and it’s strange. You’re already disoriented in this zero-gravity, off-world environment. Not much room for error in your flimsy aluminum ship, and not much of a view.

nasa3

When you look out the window, you never know whether you’ll see something familiar or some other constellation only visible to Australia. Even easily-recognizable constellations like Ursa Major can be tough to identify when they’re upside-down and you can only see through a tiny porthole. And what if your navigation equipment went dark? How would you find your way?

Navigating and orienting the space shuttle back in the ‘80s and early ‘90s was no easy feat, but with the help of HMNS VP of Astronomy and Physical Sciences Dr. Carolyn Sumners and the Burke Baker Planetarium, astronauts could practice finding their way under strange skies. As a partner with NASA, Sumners’s three-hour stellar orienteering course was required learning for every candidate astronaut aspiring to touch space.

NASA2

“The big problem was we had to limit their view to small regions, and they had to be able to find stars in areas you cannot see in Houston,” Sumners said. “We would show them a patch of sky and ask, ‘What do you recognize?’”

The original training program began with Sumners using a Spitz projector, a bulky analog contraption set on cross-braced arms that required the exchange of “star balls” for different views of the sky. The Challenger crew trained using this equipment in ’86, Sumners said. When the Evans & Sutherland Digistar 1 digital projector was installed in ’88, lessons were much easier. (Incidentally, Evans & Sutherland also developed NASA flight simulators used by astronauts at the Johnson Space Center.)

NASA1

Sumners worked closely with every crew that went into space in the ‘80s and ‘90s, working on their orienteering skills. Her class was so popular and effective, crews would occasionally drop by to brush up or re-test, or just to stop in and say hello (and made an impression when they did).

“The Apollo crew would pop in,” Sumners said. “Many of them were ex-military, so they had the buzz-cut look to them. A lot of gawking went on by the staff.”

With the advent of more reliable digital technology, crews don’t train with Sumners anymore, but partnership with NASA continues, as does her business ties to Evans & Sutherland. The newly-renovated planetarium will feature the world’s first True 8K digital projection system, the Digistar 5, and it was developed by E&S! It’s the clearest, brightest picture of space anywhere on Earth, with software that will allow audiences to see the stars not only in unfamiliar orientations near to our home planet, but from anywhere in the known universe.

ISS aurora

Coupling this projection technology with images from NASA, Sumners expects to bring audiences experiences like the view of the Aurora Borealis from a fish-eye camera mounted on hull of the International Space Station, fed directly through the Cloud.

“They should work beautifully together,” Sumners said.

Astronauts may no longer need orienteering courses, but it’s likely the clarity of this cutting-edge technology will blow even those who have been to space out of this world.