Data Outages Have Ended

The data outages caused by snow and ice ended Monday morning when the Sun melted the last pieces of ice off of the SDO antennas.
Many thanks to the FOT members who worked to keep the antennas pointed at SDO through a holiday weekend.

Data Outages Due to Snow in Southern New Mexico

Since last night, the SDO science telemetry downlink has been severely degraded due to snow and ice in southern New Mexico. The telemetry files being delivered to the SOCs have been partial for all three instruments. Accumulations of ice and or snow have probably collected on both SDO1 and SDO2 dishes. At the moment, conditions are still poor. The data outages will stop when the severe weather ceases.

Today's Occultation of Venus and the 2016 Mercury Transit Across the Sun

Today Venus will disappear behind the Moon at varying times across the United States. It will not be visible from SDO as we do not have a lunar transit today. Please see the front page of SpaceWeather.com for details on when to watch this occultation. You will need a pair of binoculars for the best view. Just find the Moon (a little ahead of the Sun in the sky) and watch as the bright dot of Venus goes behind it at about 12:30 p.m. ET.

But that brings up occultations that SDO will see. Next year we will see a transit of Mercury across the disk of the Sun on May 9, 2016. Here is a movie of the transit (using our predicted ephemeris, but it should be fairly close.)

The 2016 Mercury transit will last 7.5 hours. Mercury will touch the edge of the Sun at 1112 UTC (7:12 a.m. ET, called first contact), move completely into the disk at 1115 UTC, cross the center of the Sun at 1457 UTC, touch the far edge of the Sun at 1839 UTC, and leave the disk at 1842 UTC (2:42 p.m. ET, fourth contact). Unlike the 2012 Venus Transit, which was only visible in Alaska and Hawai'i, this transit will be visible throughout North America. People in the USA will be able to see most, if not all, of this transit.

Mercury is smaller and further from the Earth, so, compared to the transit of Venus in 2012, it will be a smaller disk as it passes between SDO and the Sun. Due to the shorter orbital period, transits of Mercury are more common than transits of Venus.

Johannes Kepler predicted a transit of Mercury would occur in November 1631. The first observed transit of Mercury was on November 7, 1631 by Pierre Gassendi. This was the first observed planet transit and showed that Kepler's equations of planetary motion could be used to predict the positions of planets.

SDO will provide near-realtime pictures of the Mercury Transit at a dedicated webpage. More details as the time approaches.

While you are waiting, grab your binoculars and go watch Venus disappear behind the Moon!

See SDO 4k Movies and Projected over Dublin

Trinity College Dublin (Ireland) is running a campaign in Dublin called City of Physics, showing the city of Dublin the beauty of physics. For their opening nights at the end of October, they projected images from the SDO instrument onto a city centre building. A short video is available to show the reaction of people in the city is at https://www.youtube.com/watch?v=mpEj_4aanDA. Check out the undergraduate students busy talking to Dubliners about SDO.

When SDO was launched TVs were displaying 720p resolution. In the five years since we have seen TV screens at 1080p and now UltraHD (3840 pixels by 2160 pixels.) This means we can show half of the Sun in full SDO resolution on commercially available screens. As a result, NASA has released a new of 4k ultra-HD movies of SDO imagery. These are also on YouTube. But to get the full impact of the UltraHD resolution you need to download the movies from SVS website.

The SDO webpage also has a list of UltraHD movies. We are planning to start releasing daily UltraHD movies.

If only UltraHD allowed us to show the entire disk of the Sun at the native resolution of the SDO imagers! But that must await the next generation of screens.

Today is Calibration Maneuver Day!

SDO will perform two calibration maneuvers today. The EVE field of view maneuver will run from 1315-1557 UTC (9:15 am-1:57 pm ET) and HMI/AIA Flatfield will run from 1630-1907 UTC (2:30-5:07 pm ET). SDO science data will not be available from 1315-1910 UTC (9:15 am-5:10 pm ET), although the AIA near-realtime images on the SDO website will show the Sun running back and forth across the images.

Another Lunar Transit Today

SDO will see another lunar transit today from 1718 UTC (1:18 p.m. ET) until 1733 UTC (1:33 p.m. ET). Although this is a very short transit, the Moon will occult part of the fine guidance system in AIA so we will turn off the fine guidance during the transit. That means the AIA images will drift a little and the HMI Dopplergrams and magnetograms will not be created.

SDO Website is back up

The maintenance on the SDO web and data servers is complete the website is back up and running normally. Thank you.

SDO website is undergoing maintenance

The SDO web and data servers are undergoing maintenance and will be unavailable for a time. We apologize for any inconvenience. We will send out a message as soon as our servers are back up.

The First Maneuver of the First SDO Extended Mission

On October 1, 2015, SDO began the First SDO Extended Mission. The SDO Team submitted a proposal to NASA in March to continue observing the Sun for another two years. The proposal was approved and we began the extended mission on October 1.

With the extended mission comes calibration maneuvers. The first is an EVE cruciform today from 1800 UTC (2:00 p.m. ET) until 2230 UTC (6:30 p.m. ET). SDO science data will not available during the maneuver but the AIA images on the SDO website will look like the Sun is zooming around in space.

Congratulations to the SDO Team for the successful proposal and winning another two years of watching the Sun and solar activity!

Movies of the Alignment at NASA

NASA has posted a feature about the alignment yesterday morning. It looks great!
http://www.nasa.gov/feature/goddard/nasas-sdo-catches-a-double-photobomb
Check it Out!

I made a short video from the AIA jpeg2000 images. You can also make these movies at HelioViewer. The motion of the Sun is caused by the telescope heating up as the Sun rises. SDO cannot run its fine guidance system without seeing the entire Sun. During an eclipse the fine guidance system is turned off and a little while after the eclipse it is turned back on.

An Alignment of the Four Most Important Objects in the Solar System

Sunday morning, September 13, 2015, we will have an alignment of the four most important objects in the solar system. SDO, the Earth, the Moon, and the Sun will form a line in space. From 0614 UTC (2:14 a.m. ET), when the Earth's edge touches the edge of the Sun, until 0721 UTC (3:21 a.m. ET), when the Moon's edge leaves the Sun, SDO's field of view will be blocked by either the Earth or Moon. The attached movie was produced by the SDO flight operations team to show how the eclipse and lunar transit will look from SDO. This is the first time an eclipse by the Earth and a lunar transit will be seen by SDO. (Although we can see features on the Earth and Moon in the video, we cannot see them in the SDO cameras.)

But that's not all! At 0655 UTC (2:55 a.m. ET) a partial solar eclipse will be visible in Antarctica. The path of the solar eclipse starts in southwestern Africa and goes almost over the South Pole. On the left is a picture from NASA's Eclipse webpage showing the path of the solar eclipse. This is the first time a solar eclipse was visible on the Earth during an SDO lunar transit. SDO cannot see the entire solar eclipse because the Earth gets in the way. The Moon was at perigee (closest point to the Earth) for the Full Moon two weeks ago. That means it is at apogee (furthest point from the Earth) for the New Moon on Sunday. The Moon will appear to be a little smaller than average so a total solar eclipse is not possible this month.

On September 28, 2015 a total lunar eclipse will be visible from most of the United States, Europe, South America and Africa. SDO does not see lunar eclipses because we look the other way. Not to worry, SDO will see another Lunar Transit on October 12, 2015 from 1718 – 1733 UTC (1:18 – 1:33 p.m. ET). It will be a grazing transit. Because SDO will not be near midnight Mountain Time, this transit will not be seen at the surface.

I hope you enjoy the Alignment of the Four Most Important Objects in the Solar System.

Comet has Faded

The incoming sungrazing comet has faded and will most likely not be visible this afternoon in SDO AIA images. This is common in Kreutz comets, they evaporate before reaching the Sun. The light curve looks like a small comet evaporating.

Here's the latest from Karl Battams: "As I expected, the comet "pulled an ISON". I won't even describe it as a comet any longer. It's a rubble pile." (SunGrazerComets).

The Comet is Still There, Waiting for the Perihelion Time Update

This morning we should get better information about the orbit of the incoming comet. The orbit from last night is shown at left (times are in UTC). The plus signs are spaced 5 minutes apart. They get a little farther apart as the comet moves from lower right to the upper left. This means the comet is speeding up. At perihelion (the closest it gets to the Sun) the comet will be moving at about 600 km/s (1.3 million mph).

We see comets because they evaporate ices and other compounds from their surface. This cools the comet, but makes it disappear. The water ice that comes off the comet quickly turns into Hydrogen and Oxygen atoms. SDO sees comet tails when the oxygen atoms hit the electrons in the corona. We can use the tails to explore the Sun's magnetic field and corona.

Most Kruetz sungrazing comets are too small to make it to perihelion (Comet Lovejoy in December 2012 was the only exception). We can only watch as this comet goes behind the LASCO occulter disks and hope it continues to evaporate and be seen in SDO/AIA images.

A New Sungrazing Comet, Will SDO See It?

Karl Battams (@SungrazingComets on Twitter) has announced a new sungrazing comet. It is seen in a LASCO image taken earlier today. The image here shows what the comet looked like at 1430 UTC (12:30 pm ET) today.

This is a Kruetz comet, like the first comet seen by SDO back in 2012. The SDO team has decided that our normal pointing at the Sun is all we need to do to capture this comet as it passes across the disk. We used the picture at left to guide us. The comet will reach perihelion (where the plus signs end) just before it goes over the limb of the Sun and disappears behind the Sun. The comet is brightest just before perihelion (if it makes it that far), there is no reason to point SDO to another part of the orbit.

We will try to post images as fast as we can tomorrow afternoon. Perihelion is at 1947 UTC (3:47 pm ET).

Welcome to the Fall 2015 Eclipse Season

Today is the beginning of SDO's Fall 2015 eclipse season. From today until September 17, 2015, the Earth will pass between SDO and the Sun once each day. SDO orbits at about the longitude of Boulder, Colorado, so the eclipse is at midnight solar time there. This corresponds to roughly 0700 UTC. Here is the first eclipse, right on schedule at 0710 UTC (1:10 a.m. MDT).

This picture shows the edge of the Earth against the Sun in AIA 193. You can see the edge of the Earth is rough, where the absorption of the Earth's atmosphere dims but does not block the light. This is different from the lunar transits, such as the one coming up on September 13, where the Moon's edge is very crisp. That transit occurs near the end of that day's eclipse and coincides with a solar eclipse in the far southern parts of the Earth.

Eclipse season is a result of our geosynchronous orbit. We don't like missing the Sun for up to 72 minutes each day. But the constant contact with SDO allows the high speed data downlink we use to bring the Sun to everyone.

Stationkeeping Maneuver #11 is Today

SDO will execute Stationkeeping Maneuver #11 today from about 2245-2315 UTC (6:45-7:15 p.m. ET). This Delta-V burn is used to keep the observatory within the assigned orbital box. During the maneuver the science data is usually not valid as the spacecraft slews away from the Sun to orient the thrusters in the correct direction.
The next eclipse season starting August 25, 2015, giving us more chances to see the Earth's limb against the Sun. Eclipse season ends September 17.

The next lunar transit on September 13 will have two firsts. The eclipse by the Earth will happen just before the transit and finish while the Moon is still crossing the Sun. At the same time a partial solar eclipse will be visible in the South between Antarctica and Africa. This will be the first time an SDO lunar transit could be seen as a solar eclipse on Earth. The movie of the combined eclipse and transit looks like a race between two spacecraft.

A month later we see another lunar transit on October 12 from 1718 to 1734 UTC (1:18-1:34 pm ET). This is more of a glancing blow but will be cool to watch.

Momentum Management Maneuver Today

SDO will perform a Momentum Management maneuver today at 1930 UTC (3:30pm ET). For about 30 minutes from 1920 (3:20 pm ET) science data will not be available. As soon the reaction wheels are at their desired speeds the science data will resume.

HMI Roll Maneuver Today

SDO will perform a roll maneuver today starting at 1630 UTC  (12:30 pm ET). The Sun may appear to rotate in images taken during this maneuver. The roll angle will be removed in the science data.

More Calibration Maneuvers

Today SDO will perform the EVE Field of View maneuver at 1315 UTC (9:15 a.m. ET) and the HMI/AIA Flatfield maneuver starting at 1630 UTC (2:20 p.m. ET. While the maneuvers are running the SDO science data is recorded but may not be usable for science studies.

EVE Cruciform Tomorrow; An SDO Cover Story

Tomorrow, July 1, 2015, SDO will perform an EVE cruciform calibration material. From 1800-2230 UTC (2:00-6:30 p.m. ET), SDO will look to and fro and up and down to allow EVE scientists to track the aging of their instrument.

Here is a collection of magazines and books that have used an SDO image as part of their cover art. There are 34 covers, and another due to come out this week! Three covers do not include an SDO image. The SDO Science Definition Team report is the beginning of the SDO mission and features SOHO artwork. The SDO Book in Solar Physics has a picture of the spacecraft on the cover. But the most intriguing is the book "Twenty-Five Astronomical Observations that Changed the World," a volume in the Patrick Moore Series on Practical Astronomy. It has a picture of Saturn, Titan, and Epimetheus on the cover. Inside it says that the EUV observations of comets near the Sun by AIA is one of the 25 observations that changed the world. That honor earned the cover a spot on the SDO Covers!

Temporary Data Outage

The SDO data system is undergoing an upgrade today, and there will be no images available until the upgrade is completed.  We're very sorry for any inconvenience.

A Flare, A CME, A Storm!

Yesterday we saw an M6.5 flare from active region 12372 followed by a filament liftoff, which turned into a coronal mass ejection, which became a a strong geomagnetic storm. Here are the NASA iSWA Kp values for the last four to show you how the Earth responded to the CME. Kp is a measure of the magnetic storm intensity, averaged over the many stations that measure the Earth's magnetic field. The NOAA SWPC has issued a G2 alert for today, meaning moderate storm activity should continue. The Kp index is described at the Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences.
Soon after the flare, another filament rose off the surface. It will probably strike the Earth's magnetosphere tomorrow (June 24). This means the geomagnetic storm will continue for awhile. Great aurora come from these storms, but they also produce energetic particles and currents in ground-based pipelines and electrical wires.
Welcome to the declining phase of Solar Cycle 24!

SDO/EVE Calibration Rocket Did Not Follow Planned Trajectory

The SDO EVE calibration rocket was cut down by range safety about 16 seconds after launch. The rocket did not fly the planned trajectory and was cut down when it appeared that it could fly out of the White Sands Missile Range in New Mexico. The payload was recovered and will be prepared to fly again. The reflight could be as soon as next year.

Launching a Sounding Rocket to Help Calibrate NASA's SDO

Tomorrow at high noon Mountain Time, the SDO EVE calibration sounding rocket will launch from White Sands Missile Range in New Mexico. It is only 15 minutes of flight with 5 minutes of solar viewing, but we use that data to calibrate the EVE and AIA instruments on SDO. The wavelengths of light these instrument measure can't be measured from the ground. Every 2 years or so we send a copy of the EVE instrument to make the same measurements as the flight instrument that orbits the Earth. The two measurements should agree and where they don't, the on-orbit instrument data is adjusted.

More details are in the SDO EVE Calibration rocket rocket article on SpaceRef or the SDO NASA webpage.

DDS offline, Back online at 0130 UTC (9 p.m. ET)

The SDO DDS went offline at about 2247 UTC (6:47 p.m. ET). The SDO Flight Operations Team is looking into the outage.

UPDATE: As of 0130 UTC (9 p.m. ET Tuesday) the SDO DDS in back online and delivering science data to the SOCs. All data downlinked while the DDS was offline will be sent by retransmissions.

IRU Calibration Maneuver is Complete

Today's IRU calibration Maneuver has finished. Here is a short movie showing what SDO did. We first pointed the high-gain antennas away from the Earth (that's why we didn't receive any science data). Next came a roll, 2 pitches, 2 yaws, 2 rolls, and a final roll back to our normal orientation. If you have ever waved your smartphone in a figure-8 to calibrate the navigation, you know what we were doing!

Thanks to the SDO FOT for taking the overnight shift to do this maneuver.

IRU Calibration Maneuver

SDO will perform an IRU Calibration maneuver on May 13, 2015 from 0400 UTC  (Midnight) to 1200 UTC (8 a.m. ET). The spacecraft will perform a series of roll, pitch, and yaw maneuvers designed to exercise the ACS. Science data may not be available during this time.

Momentum Management Maneuver #22 Complete

SDO executed Momentum Management Maneuver #22 today at 1815 UTC (2:15 pm ET). We used 48.8 gr (1.72 oz) of propellant to change the reaction wheel speeds to the desired rotation rates. Science data may be missing from 1800-1830 (UTC) while the burn was executed.

SDO 171 and 304 images get brighter

We've adjusted the settings on the AIA 171 Å (yellow) and 304 Å (orange) images - the Sun isn't getting brighter, the settings have been changed so features show up better.  The image below shows the comparison. 

Happy 5th Birthday to SDO Science Data!

Today is the 5th birthday of SDO Science Data. On May 1, 2010, SDO was commissioned as a NASA observatory and began sending science data to scientists and the public. We have watched Solar Cycle 24 rise to solar maximum, storing about 7 PBytes of data, releasing almost 200 million images, and having about 1900 scientific papers published describing new things we have learned.

I thought I would share two new images that show the solar magnetic field as only SDO can. The first is the average of the HMI magnetic field at each point on the Sun. White areas show where the magnetic field points out of the Sun and black regions are where the field points into the Sun. Grey regions have a magnetic field of zero. The Carrington longitude is used to give features on the Sun a position. We use the sine(latitude) rather than the latitude to avoid having the Sun look distorted like the Mercator maps of the Earth. The little circles are individual active regions. Even though this is an average over the last 5 years, we can see diagonal swaths of field in both the north and south hemispheres.

The other picture is how much each point on the Sun changed over those five years. The white points changed a lot while the black points changed very little. Now you see the diagonal lines a little better. Most of the changes in the solar magnetic field happen in the "active latitudes" where sunspots and flares are found. Very little happens at high latitudes. There is also very little happening along the Sun's equator.
You should compare these pictures with the averages of AIA 171 released two years ago.

SDO was launched to study the Sun's magnetic field. It is done a great job of recording the magnetic field, flares, filaments, and coronal holes during the rise of Solar Cycle 24. As Solar Cycle 24 fades SDO will continue to measure and report the magnetic field and what that magnetic field does in the solar atmosphere.

Thanks to the HMI for creating the maps of the magnetic field I used to create these pictures, and many thanks to the entire SDO team for the amazing mission they have run for the last 5 years.

SDO is GO!

Spring Maneuvers and Beakman

SDO has performed maneuvers the past two Wednesdays. The EVE cruciform on April 8 and the field of view rasters on April 15.

Today SDO was featured in Beakman Jax in the Washington Post and Annapolis Capital. Check it out at You Can with Beakman and Jax website. Look for the April 19, 2015 strip.

SDO is Back in Science Mode

SDO returned to science mode at 1534 UTC (11:34 a.m. ET). The high-gain antennas were configured for the remainder of day today through the high-gain antenna handover tonight. The HMI roll maneuver will wait until we understand what happened last night.

Many thanks to the FOT and ACS teams for recovering SDO and getting the data flowing again!

SDO is Almost Back to Normal

SDO is now pointing at the Sun with one high-gain antenna returning science data. The other high-gain antenna is pointing in the wrong direction and engineers are working on the best way to move it to the correct direction. Science data is flowing to the SOCs but interruptions may occur as the observatory is returned to the proper state.

SDO Offline

Last night at 0551 UTC (0152 a.m. ET), as SDO began the scheduled roll calibration maneuver, the ACS went into Sun-acquisition mode. SDO remains in that mode while the engineers look for the cause. The spacecraft is stable and in contact with the SDO MOC. Science data is not being taken at this time. Updates will be posted when available.

Data Delivery System in Maintenance Mode

The SDO Data Delivery System (DDS) is the interface between the antennas that receive the SDO data and the science data centers. At this time we are performing maintenance on the DDS and hope to have it back in service soon. Science data is being cached and will be delivered to the SOCs after the system is restarted.

How Loud is the Sun?

Tuesday morning was our last eclipse of the Spring 2015 eclipse season, so SDO is back to solar data 24/7.

A recent post on reddit.com asked whether the inside of the Sun would be the loudest place in the solar system.

We see millions of sound waves moving across and through the Sun. They are used to tell us about the inside of the Sun. The waves are excited by convective blobs running into the surface, like the pop you hear when a bubble hits a wall. Blobs are hitting the surface all the time, so sound waves can always be seen in the Sun. Large solar flares can also cause sound waves to ripple across the surface. Other things, such as material falling back onto the surface, might also cause sound waves, but they have not yet been detected. We don’t hear the solar sound waves at Earth because sound cannot travel through a vacuum and space is a really good vacuum. But we do see the waves as changes in the brightness or velocity of the solar surface.

After looking though the post, I interpreted this question as: What would you hear if you could put a microphone into the atmospheres of the solar system and listen to the sound waves? Where is the loudest place in the solar system?

We can and do listen to the sounds in our atmosphere, oceans, and crust. Each has rumbles at frequencies below normal sound (less than 20 Hz) or infrasound. Winds are an important source of infrasound in the atmosphere and oceans. This is easiest to imagine in the oceans. A wind pushes water into a mound on the ocean, which collapses when it gets too heavy. That falling back emits sound waves that can be measured. You also “hear” ships moving along the surface, animals communicating, and earthquakes. Although you don’t hear this when you put your head underwater, this noise is a growing problem, especially for passive sonar. Another example, the infrasound signal from the Chelyabinsk meteor entry was the loudest meteor yet recorded. It was the study of how the waves from the Krakatoa eruption of 1883 were measured in Europe and the U.S.A. that gave us the first theory of sound waves in the Sun.

You don’t hear infrasound because your ears are tuned to the sound waves needed to talk and survive. Below about 1 Hz you don’t really hear the wave so much as feel the wave. So even though the infrasound is loud, you do not sense it as it passes by unless it is really loud. This also means that the threshold of hearing for these sound waves is almost the same as the threshold of pain.

The Sun does not have fast moving winds to generate noise, but it does have convective blobs banging into the surface. They create infrasound at about 3 mHz, a frequency almost 1 million times lower what we use to talk. These sounds waves are observed moving as ripples in the photosphere, the apparent surface of the Sun in visible light.

The loudness of a sound wave can be calculated if either the pressure change or velocity of the sound wave can be measured. Solar sound waves have a measured velocity of about 10 cm/s at the photosphere. Combining that with the density (2.8 × 10^-7 g) and sound speed (8.1 × 10⁵ cm/s) at the photosphere, the loudness of these waves is about 103 dB, below the threshold of pain (130 dB), but possibly below the threshold of hearing as well. Even though there are many of these modes, you would not think the Sun is any louder than the ocean.

What is the loudest atmosphere in the solar system? The wind generates infrasound in the atmosphere and ocean. The faster the wind, the louder the noise and the lower the frequency of the noise. That means the 400 mph winds of Jupiter or the 1000 mph winds of Saturn would generate a lot of infrasound in their atmospheres. Rather than the Sun, it seems that Saturn would have the loudest atmosphere.

End note: The simplest formula to estimate the loudness of a sound wave is L = 10 log(I/I₀) = 10 log(ρ c u²/10^-9).

The First X-class Flare of 2015!

Active Region 12297 was the site of two M-class flares yesterday and an X2.1 starting today at 1611 UTC (12:11 p.m. ET). AR 12297 is in the southern hemisphere of the Sun. This movie in the AIA 304 Å shows about 90 minutes of time that includes the flare. Note the ribbon of material that lifts off the surface. 

Spring 2015 Eclipse Season has Begun

The spring 2015 eclipse season has begun! Yesterday at 0711 UTC (2:11 am ET) the Earth passed between SDO and the Sun. We can't see the Sun during the eclipse, but we do see interesting shapes as the Earth's edge moves past the Sun. The atmosphere of the Earth absorbs the extreme ultraviolet radiation from the Sun and emphasizes the bumpiness of the emissions.

This eclipse season runs until March 17, 2015.

SDO is in the News!

The San Jose Mercury News had a front-page story about predicting solar flares. Drs. Bobra and Couvidat use many kinds of data, but rely heavily on HMI magnetic field data, to predict which active regions are about to have a flare.

SDO's fifth anniversary was covered by a nice story on CNN.

Congratulations Monica and Sebastien, and congratulations to the SDO team!

SDO's Fifth Anniversary and DSCOVR's New Beginning

SDO's 5th anniversary of launch was celebrated with the release of a Five year video by the GSFC Office of Communications.

We also attended the opening of the Solarium exhibit that features SDO imagery and SOHO sounds opened yesterday at the Goddard Visitor Center. It is a cool way to watch hi-res images from SDO. The people who built SDO came by and we celebrated SDO's anniversary. (A rather interesting review appeared on this website.)

Another Space Weather spacecraft was launched yesterday. Welcome to the universe DSCOVR! Now we have two reasons to celebrate February 11.

Five Years of SDO

It is hard to believe that the SDO launch was 5 years ago! Tomorrow, February 11, is the fifth anniversary of the SDO launch. It was a cold day in Florida, but the SDO team in Greenbelt was suffering after 4' of snow! The launch was delayed because of winds on the 10th and then rose into the air at 10:23 a.m. ET on the 11th. After several weeks of trimming the observatory into an inclined geosynchronous orbit, the instrument doors opened and we began to see images of the Sun!

Since the launch AIA has taken over 100 million images, with HMI not that far behind at 80 million. EVE has returned over 12 million EUV spectra of the Sun. There have been many science results, with over 2000 papers so far presenting SDO science results. My favorite observations include the trebuchet eruption, comets in the corona, and the Transit of Venus in 2012.

SDO is a great observatory! How about 5 more years?

Today's Maneuvers

Today, February 4, 2015, SDO performed two maneuvers, the EVE FOV from 1315-1557 UTC (5:15-10:57 am ET) and the HMI/AIA Flat Field from 1630-1907 UTC (11:30 am - 2:07 pm ET). During these maneuvers the images may be blurred or not in the center of the frame. The AIA 193 Å shows SDO pointing a little below the Sun today at 1423 UTC (7:23 am ET). You can see the mask in the corners of the image.

Once the maneuvers are complete the usual data taking will resume.

Celebrate the "Year of Light" With a Beautiful SDO Image!

UNESCO has declared 2015 as the International Year of Light. A story on CNN showed NASA images to celebrate IYL2015. One image was an AIA 193 Å image like the one at left.

SDO is a great example of how astronomers use light to measure and understand our universe. AIA and EVE look at light from the Sun at very short, extreme ultraviolet, wavelengths. By comparing AIA images we can detect small motions of the corona. HMI looks at visible light. One nice property of light is that we can measure how it interacts with the Sun to measure things at the Sun that are otherwise difficult (if not impossible) to measure. We use the Doppler shift to see the wave motions and the Zeeman effect to see the magnetic field at the surface.

Light is a wonderful thing!

EVE Cruciform Today

Today, from 1800-2252 UTC (1:00-5:52 pm ET), SDO will perform the EVE Cruciform calibration maneuver. During this time the images may be blurred.

Tomorrow is the AIA GT/PZT Calibration from 1500-1620 UTC (10:00-11:20 am ET), which should cause few problems with the SDO data.

Next Wednesday, February 4, 2015, SDO will perform two maneuvers, the EVE FOV from 1315-1557 UTC (5:15-10:57 am ET) and the HMI/AIA Flat Field from 1630-1907 UTC (11:30 am - 2:07 pm ET). During these maneuvers the images may be blurred.

Yesterday's Maneuver and Today's Weather in Las Cruces

Yesterday at 1950 UTC (2:50 p.m. ET) SDO did Momentum Maneuver #21. Science data may not be available for 20 minutes on either side of the thruster firing.

There is heavy snow at the White Sands Complex near Las Cruces, NM. About 6" of snow has fallen so far. Snow can cause the Ka-band science downlink to fade, and it completely faded at 1815 UTC (1:15 p.m. ET) and has not yet returned at 1915 UTC (2;15 p.m. ET). The S-band link is not affected by the snow and is still being received. When the snowfall abates we will again receive the science data.

Update 23-Jan-2015: Normal science data flow was restarted at 2204 UTC yesterday (5:04 p.m. ET). Many thanks to the people who cleaned the snow off the antennas!

100,000,000 AIA Images!

Yesterday, January 19, 2015, at 1749 UTC (12:49 pm ET) the AIA instrument recorded its 100,000,000th image. Here it is, an AIA 193 Å image showing coronal holes in both the northern and southern hemispheres. More information, including some favorite images from team members, is available at the NASA SDO webpage.

The AIA team at LMSAL worked hard to design and build the AIA telescopes, even overcoming a delayed start way back at the beginning of the SDO project. The team continues to operate the instrument, keeping it calibrated and listing the features seen on the Sun. The HMI JSOC team at Stanford University maintains the archive that serves the images to our large and growing number of users.

Congratulations to the AIA team at LMSAL for designing, building, and running an excellent instrument for studying the Sun!

100,000,000 on my Mind

The number 100,000,000 has been on my mind this week, especially as Monday approaches.

If I traveled 100,000,000 miles I could have gone to the Sun and been 7,000,000 miles on my way home by now.

100,000,000 seconds ago was Nov. 19, 2011, a day without great significance in my calendar.

100,000,000 people lived in the USA in 1914.

100,000,000 years ago the Sarcosuchus Imperator (left) ruled the swamps and coastlines of the world. I'm glad I never met a 8000 kg (9 ton), 12 m (40 ft) long relative of todays crocodiles!

Here's a hint. SDO started returning science data on May 1, 2010. Tune in next week to find out what's up with 100,000,000!

SDO on the cover of Discover magazine's "100 Top Stories of 2014"

SDO was chosen as one of the Top Stories of 2014 by Discover magazine.  There is a beautiful SDO image on the cover.  Congratulations SDO team!

Happy Perihelion Day!

Happy Perihelion! Yesterday at 0636 UTC (1:36 am ET) the Earth was as close to the Sun as it will be in 2015. This is called perihelion. The distance change is small (about 1.67% closer at perihelion and 1.67% further away at aphelion in June), but we see the Sun as a little brighter today.

Our orbit around the Sun is almost a circle right now. That means our seasons are caused by tilt of our rotation axis. But there have been times in the past when our orbit was more of an oval. It's fun to think about what that would do to our seasons and climate. The Lensman books by E. E. Doc Smith included a nemesis with a home planet that had an extremely elliptical orbit and the bizarre evolutionary adaptations that led to.

A Big SDO Welcome to 2015!

Welcome to 2015!

There were no fireworks on the Sun last night to welcome in the New Year. Only a few C-class flares during the last day of 2014. Instead, the Sun starts 2015 with an enormous coronal hole near the South Pole. Here is an AIA 193 Å image from January 1, 2015 showing the coronal hole as a dark region in the south.

Coronal holes are regions of the corona where the magnetic field reaches out into space rather than looping back down onto the surface. Particles moving along those magnetic fields can leave the Sun rather than being trapped near the surface. Those trapped particles can heat up and glow, giving us the lovely AIA images. In the parts of the corona where the particles leave the Sun the glow is much dimmer and the coronal hole looks dark.

Coronal holes were first seen in images taken by astronauts on board NASA’s Skylab space station in 1973 and 1974. They can be seen for a long time, although the exact shape changes all the time. The polar coronal hole can remain visible for five years or longer. Each time a coronal hole rotates by the Earth we can measure the particles flowing out of the hole as a high-speed stream, another source of Space Weather.

Charged particles in the Earth’s radiation belts are accelerated when the high-speed stream runs into the Earth’s magnetosphere. The acceleration of particles in the magnetosphere is studied by NASA’s Van Allen Storm Probe mission.

As Solar Cycle 24 fades, the number of flares each day will get smaller, but the coronal holes provide another source of Space Weather that needs to be understood and predicted.

Happy New Year!