Wednesday, August 25, 2010

Regulus and Delta-H Maneuvers

On Monday around 0500 UTC, SDO pointed toward Regulus, a bright star in Leo. Half of the solar disk was kept on the CCDs and Regulus was to be a rotation indicator, helping us learn the roll angle of SDO around the Sun. Analysis of the data is continuing.

Today at 1920 UTC SDO used its thrusters to dump momentum from its reaction wheels. These wheels keep SDO pointed at the Sun as it orbits the Earth and the high-gain antennas keep turning. All that turning is transfered to the reaction wheels; every so often we have to reduce the wheel spin rates. We used 20 grams of propellant in the maneuver.

Sunday, August 22, 2010

AIA and HMI Images Unavailable

At this time we are not receiving images from AIA and HMI. The data is flowing from SDO to the JSOC, but the ground software is not creating the images we display on the SDO website. Some bandpasses are being updated, but most are not.

The problem is being worked and should be fixed soon.

Thursday, August 19, 2010

Scheduled Outage - Friday, August 20, 2010

NOTICE: This website will be down between the evening of Thursday, August 19, 2010, and the afternoon of Friday, August 20, 2010, for scheduled maintenance of the power and cooling systems.

Sunday, August 15, 2010

Another nice eruption

Yesterday morning at around 9:00 UT the Sun erupted with another beautiful coronal mass ejection. The image is from AIA at a wavelength of 211 Angstroms, click the image to see the eruption.

Saturday, August 14, 2010

Another Flare and CME

Active regions 1093 and 1099 erupted with a C-class flare and CME this morning at about 1000 UT. Here is a movie produced at LMSAL AIA showing the 193 bandpass of AIA. It looks pretty good in the various bandpasses in the Browse Data movies on this website.

Friday, August 13, 2010

Everything running normally

The SDO team works hard to keep the images and data flowing to this and other websites. Software is needed to move and analyze the images; sometimes that software breaks. Hardware is needed to host and serve the images; sometimes we lose power to a computer. We have experienced several outages the last two weeks during which the images were not available. After the outages were fixed, software was written to reconstruct the images missing from this website from the JSOC in California. We are also working to make the system more robust.

My thanks to the people who keep the data flowing.

Today we have all the images flowing correctly and the movies working. Check out a day's worth of Dopplergrams. Or what happened at about 0600 UTC this morning.

These images in 171 (left) and 304 (right) show a very nice filament eruption in the lower right limb of the Sun. The 304 bandpass is cooler material and we often see eruptions in that channel. The 171 bandpass is hotter material (about 1 million K) and is less common in the erupting material. You can see the plasma in motion by looking at the daily movies for August 13 or through our Browse Data page.

Thursday, August 12, 2010

AIA Images are Available

AIA images are once again flowing to the site.

New HMI Images are available

We are now including the HMI Dopplergrams and intensitygrams in the Sun Now section. Intensitygrams are images of the Sun in the red part of the visible spectrum. They are similar to the MDI continuum images that the Stanford group has posted during the SOHO mission, but with higher spatial resolution so you can better see the details of active regions and faculae. Right now these images are in B&W and do not have the limb darkening removed.

Dopplergrams, like the one on the left, are the raw data of helioseismology, using waves at the surface of the Sun to look inside the Sun. The Dopplergrams are also shown in B&W. Parts of the Sun moving toward you are darker and those moving away are lighter in color. The rotation velocity of the Sun has not been removed and you can see that the left side of the images moves toward SDO and the right side away. That means the Sun is rotating! The pattern seen across the surface shows a convection cell called supergranulation. The Dopplergrams need to be viewed in a movie to show the p-modes.

Movies of the images will be available in a few days when enough images have been collected. You can also visit the HMI website at to see these images.

Wednesday, August 11, 2010

AIA and HMI Images are back online

The AIA and HMI images are again flowing to the Data part of the SDO website. We are sorry for any inconvenience.

Problems with Images from AIA and HMI

At this time we are not receiving images from AIA and HMI. The data is flowing from SDO to the JSOC, but the ground software is not creating the images we display on the SDO website.

The problem is being worked and should be fixed soon.

Tuesday, August 10, 2010

Solar Cycle 24 in the Southern Hemisphere?

Solar Cycle 24 is starting to come alive and show active regions, sunspots, flares, and CMEs. On Sunday AR 11093, the large magnetic complex in the center of this AIA 171 image from August 10, 2010, had an M-class flare. Two Earth-directed CMEs have been launched in the last 10 days. The only thing that is missing is activity in the southern hemisphere. It is normal for the two hemispheres of the Sun to reach maximum at different times, but there seems to be an increasing lag, with the southern hemisphere reaching maximum later than the northern. Stay tuned!

Wednesday, August 4, 2010

CME hits Earth and causes a moderate geomagnetic storm

The coronal mass ejection from August 1 hit the Earth at 1740 UT on August 3. It caused a moderate geomagnetic storm resulting in beautiful auroral displays. This photo was taken by Tony Wilder of Chippewa Falls, WI. A second eruption may hit Earth in the next two days, perhaps causing more geomagnetic activity.

Tuesday, August 3, 2010

Coronal Mass Ejection Headed for Earth?

On August 1st around 0855 UT, the Sun let loose a C3-class solar flare. The origin of the blast was Earth-facing sunspot 1092. C-class solar flares are small (when compared to X- and M-class flares) and usually have few noticeable consequences here on Earth. This flare, however, was accompanied by a very fast coronal mass ejection that appears to be heading in Earth's direction.

Coronal mass ejections (or CMEs) are large clouds of charged particles that are ejected from the Sun over the course of several hours and can carry over ten billion tons (10^16 grams) of plasma. They travel away from the Sun at speeds than can exceed several million miles per hour, and can make the 93-million-mile journey to Earth in as little as a day.

read the rest of the article at

Monday, August 2, 2010

Will it hit Earth?

On August 1, 2010 SDO observed a beautiful prominence eruption that may hit Earth and cause a geomagnetic storm. As the solar cycle progresses and the Sun becomes more active there will be many more opportunities to observe the causes of space weather.  Want to see what happens? Follow the event at

Movie showing the eruption