By Dave Grosvold

Orion the Hunter will be at its highest point in the evening sky this month. By late March, you will notice him sliding back down toward the western horizon, just a bit lower at the same time each successive evening. Orange super-giant Betelgeuse (BEE-tel-joos) at Orion's upper left shoulder forms one apex of the Winter Triangle, with Procyon (PRO-see-yon) and blue-white Sirius forming the other two. Procyon and Sirius are the brightest stars in the two constellations that represent Orion’s faithful hunting dogs, Canis Minor, and Canis Major, respectively.

On the Apparent Magnitude scale, the higher the number, the dimmer the object, so Procyon, which is Magnitude 0.45, is dimmer than Sirius, at Magnitude -1.45. Sirius is considered the brightest star in the night sky. Venus is much brighter, at Mag -3.80.

The International Space Station (ISS) and Iridium Flares can both be brighter than Sirius, and sometimes even brighter than Venus. This week, the ISS will be almost as bright as Venus on Wednesday morning (Mag -2.9), when it passes overhead at 6:00 AM, swinging from an altitude of 20° in the WNW, up to about 43° in the SW and then back down to 10° in the SSE.

There will be four Iridium Flares visible this week, on Thursday and Friday evenings, and also Friday and Saturday mornings. These flares will be approximately Mag -2.0, so they will be brighter than Sirius in the evening and pre-dawn skies. Look for them in the south at 6:58 PM on Feb 25 (Iridium 66), and 6:52 PM on Feb 26th (Iridium 21), at an altitude of 48°. The flares will also be visible in the south at 5:35 AM on Feb 26th (Iridium 18), and 5:29 AM on Feb 27th (Iridium 39), this time at an altitude of 39° above the horizon.

The Moon entered First Quarter on Sunday, Feb 21st, so it will be waxing gibbous all week, reaching Full Moon by Sunday, Feb 28th. It will be high in the sky by 8:00 PM on Monday evening, and will then be lower in the east each successive evening. Look for the Moon between Castor and Pollux, the twins of Gemini at 8:00 PM on the 24th.

By the 25th, the Moon passes within 5° of Mars, and by the 27th the bright nearly full Moon will be only 4° below Regulus, the front shoulder of Leo. Remember, the width of your index finger held at arm’s length is about 1.5°, so three fingers would be about 4.5°.

Fiery Mars is past opposition now, so it won’t be as bright as it was last month, but it’s still a great target in a small telescope. Mars rides high in the sky this week, in a line below the twins of Gemini, about halfway between them and M44, the Beehive Cluster. Look for Mars in the eastern sky at 8:00 PM.

Saturn will be rising in the East just before 8:00 PM on the 27th. You can catch Saturn’s largest moon, Titan at about the 1:30 position in a pair of binoculars or a small telescope anytime after 8:30 PM. Remember that most telescopes either invert the image or mirror it, so you might have to look at the 7:30 or 10:30 position in your scope, unless you have an erect-image prism in the optical train.

The bright asteroid Vesta, is just past opposition and still at magnitude 6.1. Vesa continues its travels across the Sickle of Leo, as shown in the last image. You should be able to spot it in binoculars.

I recently purchased a 3rd Generation 64 Gigabyte Apple iPod Touch. The original intent was to use it to listen to Music (MP3s), watch movies, and access the internet on the go.

Basically, an iPod Touch and most of the other “Smart Phones” are miniature computers. Most use a Flash Hard Drive for storage and have rechargeable lithium batteries.

Smart Phones, such as the Apple iPhone or the Motorola Droid can access the Internet via a 3G network, which works the same way as making a Cell Phone call, i.e., the internet data is sent and received via a cell phone signal to the nearest cell tower.

Other devices, such as the Ipod Touch are not cell phones, but can access the internet through a WIFI network connection, just like a desktop or a laptop computer in your home, a coffee shop or an airport.

Apple developed the iTunes Store website to sell music, movies and software to iPhone and iPod owners.

Apple and independent computer programmers write software applications (Apps) that will do about anything imaginable. These Apps are usually very cheap, not more that a couple of bucks, or free to download. If you can think of something that you want your Apple device to do, most likely, “There Is An App For That”, including Astronomy.

The following are a few Astronomy Apps that I have found in the Apple iTunes Store that are very useful and of very high quality:

Sky Voyager: This is a very good Planetarium program that very accurately shows the locations of Deep Sky Objects, planets, the moon, stars and constellations, very similar to “Stellarium” or other planetarium software programs for computers. This App will also show the brighter comets and asteroids and identify and plot passing artificial satellites.

Pocket Sat 3: This is a free App that will predict the passage, or identify artificial satellites as the pass overhead. The orbits are projected on a image of the constellations in the night sky in real time. This App will let you know when a Satellite such as the International Space Station will appear overhead up to a year in advance. How many times have you been out at night, and wondered what that bright, moving light was. This App will tell you.

Iridium Flares: This free App will predict when, where, and how bright Iridium Flares will occur.

Moon Globe: Very similar to “The Virtual Moon Globe”, this App will help you identify or locate lunar features with a “3D Photo Quality” map.

Mars Globe: Very similar to Moon Globe, this App is for Mars, based on NASA spacecraft photos, with a “3D Photo Quality” map.

NASA App: This App takes data from NASA's Internet Website via a WIFI Connection and gives you instant access to the latest NASA News, Photos and Videos.

These are just a few of the Astronomy Apps that are available at the Apple iTune Store. New ones are added from one day to the next.

The Herschel Space Observatory has 3.5-meter primary mirror, allowing astronomers to see colder, darker celestial objects than ever before. Click image for larger view.

Exploring the universe is a bit like groping around a dark room. Aside from the occasional pinprick of starlight, most objects lurk in pitch darkness. But with the recent launch of the largest-ever infrared space telescope, it's like someone walked into the room and flipped on the lights.

Suddenly, those dark spaces between stars don’t appear quite so empty. Reflected in the Herschel Space Observatory's 3.5-meter primary mirror, astronomers can now see colder, darker celestial objects than ever before — from the faint outer arms of distant galaxies to the stealthy “dark asteroids” of our own solar system.

Many celestial objects are too cold to emit visible light, but they do shine at much longer infrared wavelengths. And Herschel can observe much longer infrared wavelengths than any space telescope before (up to 672 microns). Herschel also has 16 times the collecting area, and hence 16 times better resolution, than previous infrared space telescopes. That lets it resolve details with unprecedented clarity. Together, these abilities open a new window onto the universe.

“The sky looks much more crowded when you look in infrared wavelengths,” says George Helou, director of the NASA Herschel Science Center at Caltech. “We can't observe the infrared universe from the ground because our atmosphere blocks infrared light, and emits infrared itself. Once you get above the atmosphere, all of this goes away and suddenly you can look without obstruction.”

Herschel launched in May from the Guiana Space Centre in French Guiana aboard a European Space Agency Ariane 5 rocket. Since then, it has expanded the number of distant galaxies observed at far infrared wavelengths from a few hundred to more than 28,000. And with the instrument testing and system check-out phases finally completed, the discoveries are only now beginning.

Beyond simply imaging these dark objects, Herschel can identify the presence of chemicals such as carbon monoxide and water based on their spectral fingerprints. “We will be able to decipher the chemistry of what's going on during the beginnings of star formation, in the discs of dust and gas that form planets, and in the lingering aftermath of stellar explosions,” Helou says.

And those are just the expected things. Who knows what unexpected discoveries may come from “flipping on the lights?” Helou says “we can't wait to find out.”

Herschel is a European Space Agency mission, with science instruments provided by a consortium of European-led institutes and with important participation by NASA. See the ESA Herschel site at sci.esa.int/science-e/www/area/index.cfm?fareaid=16. Also, see the NASA sites at herschel.jpl.nasa.gov, www.herschel.caltech.edu, and www.nasa.gov/mission_pages/herschel. Kids can learn about infrared light by browsing through the Infrared Photo Album at The Space Place, spaceplace.nasa.gov/en/kids/sirtf1/sirtf_action.shtml.

This article was provided courtesy of the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

Images from EIT at 195 and 304 angstroms, MDI Magnetogram, and LASCO C3.

Virtual Moon Atlas

Carte Du Ciel

Stellarium

By Dave Grosvold

In the dark and gloomy days of winter, is there still a way to engage in observational astronomy? Did you know you can observe the Sun when it’s cloudy? Did you know you can observe the entire night sky in the daytime? What about observing the Moon when it’s not visible in the night sky? These are all possible with some help from your computer and the Internet.

Observing The Sun

The Solar and Heliospheric Observatory web site provides images of the Sun in many different forms. All of these images are taken every few minutes, so you can follow activity on the Sun in near-real time. Images from the Extreme ultraviolet Imaging Telescope (EIT) are taken in several different wavelengths of ultraviolet light (304, 171, 284, and 195 angstroms). These wavelengths correspond to different surface temperatures on the Sun, from 60,000 degrees Kelvin to over 2 million degrees Kelvin. The hotter the temperature, the higher in the solar atmosphere we see.

The Michelson Doppler Imager (MDI) captures data that provides us with a view of current sunspot activity, such as this magnetogram image. The Large Angle Spectrometric Coronagraph captures activity in the solar corona by blocking out the overwhelming light from the Sun itself so the delicate corona can be seen. This allows us to see streamers and radial bands in the corona that would otherwise be invisible. Visit SOHO Explore! to learn more about the Sun and how it works.

Virtual Moon Atlas

Want to observe the Moon? The Virtual Moon Atlas is a free software download available for Windows, Mac, and Linux PCs that allows you to view very high resolution photographs of the entire surface of the Moon. There are thousands of identifiable features and a huge amount of detailed information, including multiple scientific overlays, including rock types, presence of certain trace elements, altitudes, surface temperature, iron oxides, etc.

The program is available in over a dozen languages, with complete documentation, quick star guides, and a multitude of downloadable add-ons including textures and picture libraries. PocketLun, the Pocket PC version of VMA is even available for Windows Mobile devices. VMA is a professional-level program and will provide even the advanced the Lunar Observer with hours of observational study.

Charts and Planetariums

There are a number of free sky chart programs on the market. The most notable is Carte Du Ciel (literally “Sky Charts”,) by Patrick Chevalley, the author of Virtual Moon Atlas mentioned above. Carte Du Ciel (CDC) has as many databases available as many of the expensive commercial offerings, and charts can be printed to great detail - as deep as most, if not all, printed star atlases. Many amateur astronomers use CDC as their software tool of choice when it comes to controlling a telescope in conjunction with their astroimaging equipment.

There are also planetarium programs free for the download, such as Stellarium. Stellarium displays the night sky much as it would look to a naked-eye observer out under the stars. This includes such things as light pollution, fog, meteors, and the effects of the full moon and sun in the sky. Stellarium can be used as a basic charting program, but printing charts is not it's forte. It's much more at home displaying the night sky in a realistic way. Stellarium has a planetarium projection mode that can be used with an appropriate projector to display the entie night sky form horizon to horizon in a dome. See their web site for more information.

Both of these programs are great tools and would be welcome in any amateur astronomer’s kit.

WorldWide Telescope

On a cold gloomy night in January, though, the best way to view the heavens is with WorldWide Telescope. WWT is a free product from Microsoft Research, and is available in the form of a Web Client for Mac, or as a download for Windows, that basically turns your computer into a Virtual Telescope. WWT brings together images from some of the world’s largest ground and space-based telescopes in a way that allows you to explore the universe in a seamless virtual environment.

WWT view of Jupiter

The images are breathtaking, and WWT provides a large number of guided tours that allow you to travel on a exploratory journey along with various astronomers from famous observatories and universities. See how dust in the Milky Way condenses into stars and planets! Travel 2 billion years into the past and learn how gravitational lensing works!

So you can’t get outside and see the night sky? Observe anyway, using these fantastic tools and the Internet!

By Dave Grosvold

The real astronomical treat this week will not be planets, stars, or even comets, but man-made objects in the heavens. Iridium Flares are the result of sunlight reflecting off the surface of Iridium Satellites as they pass overhead.

Flare from Iridium 84, November 20, 2006 at 7:06 PM CST. Andrew Echols Photo.

Iridium Satellites are telecommunication satellites launched in 1997 and 1998. There are about 70 Iridium Satellites currently in orbit. What makes them interesting is that their particular shape and antenna configuration contribute to the occurrence of very bright flares – sometimes so bright they can be seen in daylight. The flares last only a few seconds, but are most impressive at night. You can view a flare simulation on Wikipedia.

These flares can reach a brightness nearly twice that of Venus at maximum, or nearly −8.0 in apparent magnitude, a measure of the apparent brightness of an object in the night sky when viewed from Earth. Although there will be several flares over the next week, there are two that will be visible in the evening. On Wednesday evening, January 20th, Iridium 50 will pass overhead to your NE at approximately 6:55 PM. Look for it at about 52° above the horizon. Remember – straight up (the zenith) is 90° above the horizon, so 52° is more than halfway from the horizon to the zenith. To make sure you see it, start observing at about 6:50 PM CST, and continue until at least 7:00 PM. It’s even better if you have several people looking in different parts of the sky.

On Thursday, January 21st, Iridium 53 will take nearly the same path across the sky, but just a bit earlier, at 6:49 PM CST. On Thursday, start looking at 6:45 and continue until about 6:55 PM. Look to the NE at an altitude of about 52° If you’re adventurous, Iridium 54 and Iridium 13 will pass at a low altitude of 22° in the SSE just after sunrise at 6:25 AM CST on Thursday, January 21st and at 6:10 AM CST Monday, January 25 respectively. These may be difficult to spot, but they are bright enough to see for sharp-eyed observers.

Saturn as viewed in a small telescope, 1:00 AM CST Thursday, January 21, 2010.

The International Space Station (ISS) will also make several bright passes in the evening this week, each brighter than Sirius, the brightest star in the night sky. The ISS is visible over a much larger path in the sky than Iridium Flares, and consequently stays visible for a longer period of time.

On the evening of Thursday, January 21st, the ISS will pass low in the N starting at 6:09 PM CST. It will swing higher to a maximum altitude of just 16° above the horizon in the NE, then pass low to the ENE over a period of about 6 minutes. You can estimate 15° of altitude on the sky by viewing the width of your fist held at arms’ length.

Observers get another chance at ISS on Friday, January 22nd. This time, the ISS will rise above the horizon in the NW at about 6:30 PM CST, swing high overhead to about 45° altitude in the NE, and then sink back to the horizon in the ESE, again over about a six minute period.

On Saturday, January 23rd, the ISS makes another pass from the NW at about 6:51 PM CST over to the SW at a maximum altitude of 40°, and then back toward the horizon in the SSW at about 6:58 PM. Amateurs have reported seeing the shuttle docked at the station in small telescopes as it passes overhead in the past. However, no shuttle missions are in progress at this time.

Also, Mars and Saturn dominate the eastern sky after sunset once again this week. Mars rises at about 6:30 PM CST, and is high enough in the East by about three hours after sunset to see clearly in small telescopes. Saturn rises much later - after 10:30 PM. It will be 1:00 AM or so before Saturn is high enough above the thick eastern atmosphere for observing. You may spot several of Saturn’s largest moons, including Titan in a small telescope.

by Patrick Barry

These images are TES ozone plots viewed with Google Earth. Colors map to tropospheric ozone concentrations. The image on the left shows ozone concentrations at an altitude of approximately 32,000 feet, while the one on the right shows ozone at approximately 10,000 feet. The measurements are monthly averages over each grid segment for December 2004. Click image for larger view.

When it comes to notorious greenhouse gases, carbon dioxide is like Al Capone—always in the headlines. Meanwhile, ozone is more like Carlo Gambino—not as famous or as powerful, but still a big player.

After tracking this lesser-known climate culprit for years, NASA’s Tropospheric Emission Spectrometer (TES) has found that ozone is indeed a shifty character. Data from TES show that the amount of ozone—and thus its contribution to the greenhouse effect—varies greatly from place to place and over time.

"Ozone tends to be localized near cities where ozone precursors, such as car exhaust and power plant exhaust, are emitted," says Kevin Bowman, a senior member of the TES technical staff at the Jet Propulsion Laboratory. But the ozone doesn't necessarily stay in one place. Winds can stretch the ozone into long plumes. "Looking out over the ocean we can see ozone being transported long distances over open water."

Unlike CO2, ozone is highly reactive. It survives in the atmosphere for only a few hours or a few days before it degrades and effectively disappears. So ozone doesn't have time to spread out evenly in the atmosphere the way that CO2 does. The amount of ozone in one place depends on where ozone-creating chemicals, such as the nitrogen oxides in car exhaust. are being released and which way the wind blows.

This short lifespan also means that ozone could be easier than CO2 to knock off.

"If you reduce emissions of things that generate ozone, then you can have a quicker climate effect than you would with CO2," Bowman says. "From a policy standpoint, there’s been a lot of conversation lately about regulating short-lived species like ozone."

To be clear, Bowman isn’t talking about the famous "ozone layer." Ozone in this high-altitude layer shields us from harmful ultraviolet light, so protecting that layer is crucial. Bowman is talking about ozone closer to the ground, so-called tropospheric ozone. This "other" ozone at lower altitudes poses health risks for people and acts as a potent greenhouse gas.

TES is helping scientists track the creation and movement of low-altitude ozone over the whole planet each day. "We can see it clearly in our data," Bowman says. Countries will need this kind of data if they decide to go after the heat-trapping gas.

Ozone has been caught red-handed, and TES is giving authorities the hard evidence they need to prosecute the case.

Learn more about TES and its atmospheric science mission at tes.jpl.nasa.gov. The Space Place has a fun “Gummy Greenhouse Gases” activity for kids that will introduce them to the idea of atoms and molecules. Check it out at spaceplace.nasa.gov/en/kids/tes/gumdrops.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

By Dave Grosvold

Looking east at 9:00 PM CST Jan 14, 2010

January 2010 is a great time to observe Mars. This is the time just before the Red Planet passes closest to earth in its 687-day journey around the Sun. When Mars appears bright in the night sky, it is in opposition to the Sun, meaning that it is opposite the Sun in the sky as seen from Earth. It is also closer to Earth at this time than at any other time in its orbit. As such, this is when it is brightest and best positioned for observational study. Whenever Mars or any other planet is visible in the night sky for a period of weeks, this entire period is said to be a single apparition. Mars’ latest apparition began several weeks ago. This week, you will see it above the eastern horizon early on clear cold evenings as a bright ruddy “star”. By 9:00 PM, it will be high enough above the horizon that you can view Mars without the usual distortion caused by the thicker atmosphere lower on the horizon.

Looking west-southwest at 6:00 PM CST Jan 17, 2010

Mars will actually make its closest approach to us in its orbital cycle on January 29, 2010. As Mars approaches opposition it begins a period of retrograde motion, which means it will appear to move backwards in a looping motion with respect to the background stars. This is due to the fact that Earth passes Mars in its orbit. So initially, we see it in front of us, and then as we pass, it falls behind. The duration of this retrograde motion lasts for about 72 days, and Mars reaches its peak luminosity in the middle of this motion this coming March.

Careful observers should be able to identify the larger features on Mars’ surface using a small telescope. These include the polar ice caps and Syrtis Major, which appears as the largest dark splotch on Mars. These darker areas were once thought to be seas or canals, but have been revealed as areas of darker rock with less dust than the brighter surroundings.

Also this week, Jupiter is low in the southwest just after sunset. Jupiter will continue to get lower in the western sky every evening until it sinks below the horizon. On Jan 16, if the sky is clear, look for the waxing crescent Moon very low on the western horizon. By the evening of Jan 17, the Moon will be very close in conjunction below Jupiter in the western sky. A conjunction occurs when two or more celestial objects appear very close together in the night sky.

By Dave Grosvold

The Moon and Saturn at 12:00 AM CST Jan 6, 2010

With the colder weather and snow this time of year, astronomical observing is usually limited to fairly short sessions. Although the cold is hard on the observer, it is also hard on the equipment. So, naked-eye targets are ideal for winter observing. At midnight on Tuesday evening, the Moon rises very close to bright, pale yellow Saturn, and will be far below the Red Planet (Mars) in the sky. This week, the Moon enters Last Quarter at 4:39 AM CST on Thursday morning, so it won’t be quite as bright as it was on New Year’s Eve.

Saturnian Moons, 4:00 AM CST, Jan 7, 2010.

With the aid of a small telescope, you may also be able to see Titan, Saturn’s largest moon in the early morning hours if the sky is clear. At about 3:30 AM all this week,Saturn is high enough in the sky to rise above the “muck,” which is what astronomers call the thicker part of the atmosphere that we must look through when objects are close to the horizon. A view in a small scope will show Titan off to the right at about 2 o’clock. The image shown here will be reversed in the telescope’s field of view.

Early January is also a great time to observe the Great Orion Nebula, as it is in an ideal position by about 10:00 PM on these cold winter nights. The constellation of Orion rides high in the South-Southeast in late evening all week this week, and the Great Nebula is a special treat for anyone with a good pair of binoculars or small telescope. Orion is recognizable by his belt and sword.

Fantasy image of a Blue Moon

Blue Moon Endings

The Full Moon on Thursday, December 31st marks a rare ending this year. There are normally 12 full lunar cycles in a year, but some years have 13. The thirteenth moon is sometimes known as the Blue Moon. Although different definitions place the blue moon at different times of the year, at least one definition places it at the end of the year.

A March 1946 article in Sky and Telescope magazine by James Hugh Pruett misinterpreted the 1937 Farmer’s Almanac to mean that the second full moon in a calendar month was called the Blue Moon. This “misinterpreted” definition of a Blue Moon has come into widespread use in recent years after it was revived on the January 31, 1980 installment of the popular radio program StarDate.

There are several other astronomical definitions for a “Blue Moon”, but the two cited above make this coming Thursday’s Full Moon a Blue Moon. By either definition, this only happens every few years. Just remember — it’s referred to as a blue moon, but the Moon won’t look blue — it will look the same as any other full moon.

In any event, it’s an appropriate way to punctuate not only the end of 2009, but the end of the only decade in a thousand years where we’ll refer to the year as “something-thousand-something” rather than the more common “nineteen- or twenty-something-something.” I guess a situation like that only happens “once in a very blue moon...”

Sky view looking east at 9:30 PM on Jan 2, 2010

The Wandering Stars

Planet, in Greek, means wanderer. These objects are so named because they appear to move from night to night against the fixed background of the stars. A feast of planets is visible in the evening sky this week, even with the glare of the Full Moon.

Jupiter, known as the King of Planets, will be visible as a bright object low in the southwest just after sunset. Jupiter sets in the west by about 9:00 PM, and will only be visible in the evening sky for another month or so. After that, it sinks below the horizon before sunset - too early to be seen for observers in our part of the world. Binoculars or small telescopes will reveal Ganymede, Callisto, Io, and Europa, the four brightest moons of Jupiter. Observing these at different hours of the night and on subsequent nights will show obvious movement with respect to each other and Jupiter. So far, scientists have discovered over sixty three moons orbiting the giant planet.

Neptune is approximately 1-1/2° lower toward the western horizon than Jupiter, and is much harder to spot. A small telescope will reveal it as an obvious disk with a blue-green cast, rather than as a point source. You can measure 1° on the sky by the width of your pinkie finger held at arm’s length. Neptune will set only about 6 minutes earlier than Jupiter.

Saturn presents a great observing target for those who might be awake in the early morning hours. Saturn’s rings are at just 4° from edge-on right now, so the planet looks much like a “spike in a ball” in small telescopes. The ring angle will open somewhat in 2010. Saturn will be rising in the east just before midnight, and will be appear to be a bright object with a slightly yellow cast. Small telescopes will reveal the rings and perhaps up to six of Saturn’s brightest moons — Titan, Hyperion, Rhea, Dione, Tethys, and Mimas. These will be stretched out along the same plane as the ring system. Of all the moons in the Solar System, Titan is unique in that it is the only one that has an atmosphere. Saturn has over sixty-one known moons.

Mars rises big and bright at about 8:00 PM and should be visible all night. Mars is in one of it’s close approaches (or opposition) to Earth during the month of January, and should be easy to observe. Small telescopes should show enough detail to see the markings or “canali” that lead early observers to believe there was an active civilization on the Red Planet. These markings were first observed by Giovanni Schiaparelli during the opposition of 1877, and he dubbed them canali, which is Italian for canals or channels. Improved astronomical observations in the early 20th century proved this to be false. Look for Mars in the east as a brilliant object with a ruddy hue. On Saturday, Jan 2nd, Mars and the Moon will rise together about 7° apart in the eastern sky. For reference, 7° of sky is about the width of four fingers held at arm’s length.

By Patrick Barry

X-9 class solar flare December 6, 2006, as seen by GOES-13's Solar X-ray Imager. It was one of the strongest flares in the past 30 years.

In December 2006, an enormous solar flare erupted on the Sun's surface. The blast hurled a billion-ton cloud of gas (a coronal mass ejection, or CME) toward Earth and sparked days of intense geomagnetic activity with Northern Lights appearing across much of the United States.

While sky watchers enjoyed the show from Earth's surface, something ironic was happening in Earth orbit.

At the onset of the storm, the solar flare unleashed an intense pulse of X-rays. The flash blinded the Solar X-Ray Imager (SXI) on NOAA's GOES-13 satellite, damaging several rows of pixels. SXI was designed to monitor solar flares, but it must also be able to protect itself in extreme cases.

That's why NASA engineers gave the newest Geostationary Operational Environmental Satellite a new set of sophisticated “sunglasses.” The new GOES-14 launched June 27 and reached geosynchronous orbit July 8.

Its “sunglasses” are a new flight-software package that will enable the SXI sensor to observe even intense solar flares safely. Radiation from these largest flares can endanger military and civilian communications satellites, threaten astronauts in orbit, and even knock out cities' power grids. SXI serves as an early warning system for these flares and helps scientists better understand what causes them.

“We wanted to protect the sensor from overexposure, but we didn't want to shield it so much that it couldn't gather data when a flare is occurring,” says Cynthia Tanner, SXI instrument systems manager for the GOES-NOP series at NASA's Goddard Space Flight Center in Greenbelt, Maryland. (GOES-14 was called GOES-O before achieving orbit).

Shielding the sensor from X-rays also reduces the amount of data it can gather about the flare. It's like stargazing with dark sunglasses on. So NASA engineers must strike a balance between protecting the sensor and gathering useful data.

When a dangerous flare occurs, the new SXI sensor can protect itself with five levels of gradually “darker” sunglasses. Each level is a combination of filters and exposure times carefully calibrated to control the sensor's exposure to harmful high-energy X-rays.

As the blast of X-rays from a major solar flare swells, GOES-14 can step up the protection for SXI through these five levels. The damaged sensor on GOES-13 had only two levels of protection — low and high. Rather than gradually increasing the amount of protection, the older sensor would remain at the low level of protection, switching to the high level only when the X-ray dose was very high.

“You can collect more science while you're going up through the levels of protection,” Tanner says. “We've really fine-tuned it.”

Forecasters anticipate a new solar maximum in 2012-2013, with plenty of sunspots and even more solar flares. “GOES-14 is ready,” says Tanner.

For a great kid-level explanation of solar “indigestion” and space weather, check out spaceplace.nasa.gov/en/kids/goes/spaceweather.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.