Temporary Interruption in browse data

There is a temporary interruption in the service of browse data on the SDO website. http://sdo.gsfc.nasa.gov/data/kiosk.php and http://sdo.gsfc.nasa.gov/data/aiahmi/ are temporarily offline. We are working to get it back up as soon as possible.
Today, tomorrow, and Thursday we will be running tests of the Venus transit image sequences. During these tests the AIA images may be partial images or even striped images. These are designed to send data more suitable for studying the effects Venus will have on the data. Please be patient while we explore new ways to use the instrument.

Delta-H Maneuver Today at 1800 UTC

Today at 1800 UTC we will perform our 10th momentum management (Delta-H) maneuver. Data will unavailable from the SDO instruments from 1800 until 1824 UTC (2:00-2:24 pm ET) while the thrusters are fired to change the reaction wheel speeds. Reaction wheels are used to keep SDO very accurately pointed at the Sun. These burns keep the reaction wheels within their speed limits.

How Big are Today's Sunspots?

As we move through solar maximum in the solar north we can start comparing Solar Cycle 24 with other data. Here is a comparison of the active region 11476 in an HMI image from May 11, 2012 with the Earth (small dot) and Jupiter (big dot). AR 11476 covered about 1100 area units at its largest size. People claimed it was as big as Jupiter! We can see here that the dark core part of 11476 (called the umbra) was still quite small. Even though the entire sunspot was about half the size of Jupiter, it is mostly the dimmer penumbra.

Compare with the largest sunspot we have in a photograph, AR 14886 from April 7, 1947. We put the Earth and Jupiter disks in again and see that AR 14886 is larger (6000 units) than AR11476, still a little smaller than Jupiter (which is 10,000 units), and the dark umbra appears to occupy a larger fraction of the sunspot. (Original picture is courtesy of the Carnegie Institution of Washington.) One of the largest sunspot in Solar Cycle 23 was 10486, which caused the massive Halloween storms of 2003. It was 2600 units at its largest. The largest sunspots tend to occur after solar maximum and the larger sunspots tend to last longer as well. As we move through solar maximum in the northern hemisphere and look to the south to pick up the slack there should be plenty of sunspots to watch rotate by SDO.
CHECK IT OUT: SDO images are featured in the June issue of National Geographic!

Still Active in the North, AR 11476 Flares Up!

The SWPC in Boulder issued a flare alert after an M-class flare in active region 11476. Here is an EVE plot from noon today showing the history of spectral irradiances. We usually look at the blue line in the top panel, the ESP 0.1-7 nm radiometer. It is very similar to the GOES X-ray measurements. The M-class flare is the spike in the blue line just after 0400 UT today. The dark count is a measure of the energetic particles hitting SDO and usually rises around 1800 UT each day because of the Earth's radiation belts.

Space Weather Message Code: ALTXMF
Serial Number: 170
Issue Time: 2012 May 10 0418 UTC

ALERT: X-Ray Flux exceeded M5
Threshold Reached: 2012 May 10 0417 UTC
NOAA Scale: R2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/NOAAscales

Potential Impacts: Area of impact centered on sub-solar point on the sunlit side of Earth. Extent of blackout of HF (high frequency) radio communication dependent upon current X-ray Flux intensity. For real-time information on affected area and expected duration please see http://www.swpc.noaa.gov/drap/index.html.

Venus transit testing is over

The AIA Venus transit testing is over and images are flowing to the various archives.

Venus Transit Testing

Today at 1800 UT (2 pm ET) the AIA instrument started testing the instrument modes they will be using during the Venus transit on June 5-6. AIA images will be unavailable until the testing is complete (about 30 minutes). Some of the partial and striped images may be visible. There is nothing wrong with AIA and we will return to our normally scheduled pictures as soon as the testing is finished.

An Echo of a Lunar Transit

Some pictures from SDO go the long way 'round! Here is an AIA 304 image taken during the April 21, 2012 lunar transit and the same image sent to the moon, reflected back to the Earth and reconstructed by Daniela de Paulis back on Earth. I wonder if this is what the SDO images would look like if they were received by someone on Polaris? The striping in the lower image is visual static. It is what the hiss between radio stations would look like if you made it into a picture rather than listened. I do wonder why the noise has blue dots.
More information about sending images to the moon and back can be found the OPTICKS website.