SDO | News & Resources

SDO Mission Blog

This is the Solar Dynamics Observatory Mission blog. It will consist of mission status, news, and event updates.

Today's Joint Solar Eclipse looked beautiful from SDO. Here's a short movie in AIA 193 to show you what it looked like. It starts with the Earth between SDO and the Sun. As the Earth moves out of the way, you can see the disk of the Moon covering part of the Sun. The wobbling of the Sun is due to SDO turning off the fine-guidance system during the Earth eclipse.

Meanwhile, solar physicist Ryan Milligan was traveling in Tanzania and saw the eclipse from the ground. Here is a lovely picture of an annular eclipse — not quite total, but better than partial. This picture is a excellent example of a "Ring of Fire". The different views of the Sun, SDO seeing a partial eclipse of the Sun by the Moon while parts of Africa saw an annular eclipse, come from SDO's position to the East of Africa, a little North, and far out in space.

Thanks to Ryan for letting me show his post. You can see more of his eclipse pictures at

Today at 1857 UTC (2:57 p.m. ET) SDO will do MM #27. Science mode will stop at 1847 UTC and resume at 1917 UTC (3:17 p.m. ET). Science data may be blurry or absent during that time.
Tomorrow morning between 0715 and 0731 UTC (3:15-3:31 a.m. ET), SDO will see a lunar transit as SDO exits an Earth eclipse. Parts of Africa will observe an annular solar eclipse at the same time. While these double eclipses were rare early in the SDO mission, two have happened in the last year. The SDO flight dynamics team cannot yet tell whether we will see another one next year. Even though the Sun and Moon loom large in our images, they are actually quite small and SDO's view may have the Moon outside of the Sun next September.

Enjoy the 2016 SDO Joint Solar Eclipse!

Today from 2240-2305 UTC (6:40-7:05 p.m. ET) SDO will execute a station-keeping maneuver that keeps us within our assigned longitude box. The instruments may return data during this time, but it could be blurry.

Looking forward to September we have another lunar transit on September 1, 2016 from 0715-0731 UTC (3:15-3:31 a.m. ET). This transit will start while SDO is in the shadow of the Earth. That means when we see the Earth move out of the way the Moon will be covering part of the Sun. While these double transits did not happen the first 5 years of the mission, we may see a couple more as the Moon's orbit slowly shifts.
Here is a movie from the flight operations team showing the double transit.

On August 31, 2016, SDO will perform the EVE field of view and HMI/AIA Flatfield Maneuvers. More on that later.

I had forgotten how nice it was to see the Sun each morning in all of the different ways SDO provides.

It took longer then we expected, but as of the end of the Friday work day, SDO is in science mode and all three instruments are returning science data. AIA is currently taking images with the nominal 8 images every 12 second program but it is running an older version of flight software that is affecting the Image Status Packet. We plan to leave the system in this configuration over the weekend.

It's been a long week for the SDO team and I hope they can return Monday ready to fix the remaining issues.

Thanks to all who helped SDO to return to operations.


SDO had a lunar transit this morning from 1113-1207 UTC (7:13-8:08 a.m. ET). The spacecraft did not go back into Science mode at the end of the transit. SDO FOT members are looking into the issue.
SDO will perform an EVE cruciform maneuver today. From 1700-2152 UTC (1:00 p.m.-5:52 p.m. ET), SDO will rock up and down and back and forth as a calibration maneuver. During this time the AIA and HMI images may be blurred or blank.
SDO will perform momentum management maneuver #26 today from 1945-2000 UTC (3:45-4:00 p.m. ET) today. Science data is not returned during the maneuver.
We are starting the July maneuver season. Today is the HMI roll maneuver from 1500-2000 UTC (11 am ET to 4 pm ET). During the roll the Sun will appear to flip in the NRT data. This data is used to maintain the calibration of HMI and to study how round the Sun is.
Earlier the week we received our conjunction report that lists satellites that will pass close to SDO. Our inclined geosynchronous orbit means there aren't a lot of satellites near SDO, but every couple of months one will come within 20 km (12 mi) of our spacecraft. This week saw the return of Telstar 401 to our list (see the picture at left.) Telstar 401 is a large telecommunications satellite that failed January 11, 1997, and has since drifted around the geostationary belt of satellites. This is not a small satellite, the solar panels stretch about 60 ft across. It's good to know the other satellite is around, but it would be better if was moved to a graveyard orbit well outside of the geostationary belt.

It is possible that Telstar 401 failed because of the activity created by a coronal mass ejection that rose off the Sun on January 6, 1997. (The gray picture at left shows what the CME looked like at 1850 UTC on that date.) The CME is the white arc moving down from the occulting disk. It is called a halo CME because we see it as a ring around the Sun, which means it is heading straight towards Earth!

The impact of the CME was not very dramatic when it reached Earth a few days later. But the energies of the radiation belt protons and electrons were increased enough that they caused an electronic component to arc and fail. There were several attempts to revive Telstar 401, but it was eventually declared a loss.

According to the Union of Concerned Scientists, there are almost 500 satellites currently operating in geosynchronous orbits about the Earth. Most of them are in the geostationary belt that allows them to appear stationary in the sky. There are about 100 defunct satellites in graveyard orbits further away from the Sun. But it is the failed satellites and spent boosters that blunder along and show up on the SDO conjunction report every month or so.

Telstar 401, a true ghost of space weather!

Today at 2234 UTC (6:34 pm ET) is the summer solstice for 2016. It's also a full moon today, the first time the summer solstice and full moon have coincided since 1967. Enjoy the longest daytime of the year and a bright night as well. Maybe we could celebrate the brightest day of the year?

Today I would like to share another picture from the May 9, 2016, Mercury transit. This is a composite created by Monica Bobra at Stanford University. It's an excellent view of the transit from 2nd contact to 3rd contact, with an image every 20 minutes. Creating these composites takes a good bit of art. You can't just add the images together as that blurs the background image of the Sun. You have to take cutouts around the planet and reinsert them in a selected background image.

It turns out that MDI on SOHO was turned on for the transit. Bobra did the same analysis to produce this image from MDI. The data near 2nd contact is not available.

You can see the paths of Mercury are slightly different in the two images. The MDI path is closer to the solar equator and tilted at an angle to the path in the HMI image. These differences are caused by the different viewpoints of the transit from the two spacecraft. Similar differences are what were measured to determine the size of the astronomical unit (AU) during the Venus transits of the 1700 and 1800's.

Thanks, Monica!