EVE Field of View and HMI/AIA Flatfield Today

Today, starting at 1315 UTC (8:15 am ET), SDO will execute the EVE Field of View maneuver followed by the HMI/AIA Flatfield at 1630 UTC (11:30 am ET). During these maneuvers the science data will be interrupted. These maneuvers and last weeks' Delta-H thruster firing were flipped in the schedule published earlier.

Momentum Management Maneuver Today

Today at 1946 UTC (2:46 pm ET) SDO will fire its thrusters to change the spin rates on the reaction wheels. The science data will stop at about 1940 UTC and resume at 2006 UTC. We use these reaction wheels to keep SDO pointing at the Sun. They change their speed as SDO orbits the Earth to counteract the torques caused by solar radiation pressure, magnetic dipole, and the gravity gradient in our orbit, and the high gain antennas. When the rates approach the limits, we use the thrusters to drive them back. UPDATE: The thrusters fired successfully and used 66 grams of propellant during the burn.

Ben Franklin's Birthday

January 17 is the birthday of Benjamin Franklin, born this date in 1706. He was a scientist, diplomat, and printer. He also studied sunspots. In a letter to Humphry Marshall he wrote "It is however remarkable that tho’ large Spots are seen gradually to become small ones, no one has observ’d a small Spot gradually to become a large one; at least I do not remember to have met with such an Observation."

This letter was sent in February 1773 from Franklin in London to Marshall in Pennsylvania. At this time an ongoing scientific debate was whether science in England was the same as science in the North American colonies. Franklin synchronized experiments on both sides of the Atlantic to explore whether electricity behaved the same. Observations of the Sun were part of this effort.

Happy Birthday, Ben!

SDO Maneuvers for Early 2013

We have announced maneuvers and special operations for the first eight months of 2013
16-Jan-2013: EVE Cruciform
23-Jan-2013: EVE FOV & HMI\AIA Flat Field
30-Jan-2013: Delta-H #13
17-Feb-2013: Handover Season Begins
03-Mar-2013: Eclipse Season Begins
07-Mar-2013: Solar RFI (~418 seconds)
08-Mar-2013: Solar RFI (~440 seconds)
20-Mar-2013: Station Keeping Maneuver #06
25-Mar-2013: Eclipse Season Ends
10-May-2013: Handover Season Ends
06-Aug-2013: Lunar Transit (~76 minutes)
Each maneuver comes with a loss of solar pointing or interference with the radio downlink.

Happy New Year 2013!

As we begin another year, how about a disk problem? It appears that the SDO webserver didn't change smoothly to 2013. It will be fixed as soon as possible. 

Holiday Greetings from the SDO Team

Happy Holidays from the SDO Team. Thanks for making SDO images appear all around the globe. From looking at comets to the Transit of Venus, we are glad the data is so useful.

The past year has seen an explosion in the science output of SDO! We look forward to many more years of studying the Sun's magnetic field.

We also made the cover of Jan/Feb 2013 issue of Discovery magazine. Look for it!

One Year Since Comet Lovejoy's Perihelion

It has been one year since Comet Lovejoy was watched by SDO, STEREO, and Hinode as it passed by the Sun. Each spacecraft provided unique observations we had not anticipated when they were built and launched. Hinode took an image of the coma in reflected sodium light. SDO and STEREO provided images in the EUV that we continue to analyze. Here is one picture from the movie comet_swoosh_171.mp4 on the SDO Comet Lovejoy Event Page. The streaks across the path of the comet have become the fascinating part of the comet tail.

In the past year we have figured out one way the comet tail can be bright in the solar corona. (Check out the paper at the Physics ArXiv site.) But we still don't know how the solar magnetic field affects (and is affected by) the comet as it moves through. All of that stuff coming off the comet makes the field shake, can we learn something from that? The brightness of the comet debris comes from running into electrons in the corona. Can we learn about the number of electrons in the corona?

We need even bigger sun-grazing comets!

Since Comet Lovejoy we have had only one alert to look for a comet in SDO and we saw nothing. But Comet ISON is due on Thanksgiving Day next year. It was acquired out near Jupiter, which usually means it is a big comet. As it moves toward the Sun, people are watching to see if stays bright. If it does we will be in for quite a show. Comet Lovejoy came in from the south and was seen only in the southern hemisphere. Comet ISON is coming in from the north and could be visible from the United States both inbound and outbound. Comet ISON will also pass through the corona a little farther out than did Comet Lovejoy, 1.2 million km (1.9 million miles) above the Sun's surface.

It would be like fireworks on Thanksgiving!