Thursday, December 22, 2011

AIA Camera-4 Fault

AIA's Telescope Assembly ATA-1 suffered a misnamed Camera-4 anomaly. It is visible in the Sun Today images as well as in the FITS files. Here is an example from the 335 channel, where the dark area circled and the "scan lines" pointed at are example of a Camera-4 fault. The fault is automatically cleared within a few images but tends to reoccur until the camera is reset. These flaws will be visible is some 335 and 131 images between 12/22 13:15:17 UT and the reset at 19:37:54.

Monday, December 19, 2011

The SDO ground station complex Near White Sands, New Mexico is currently receiving snow and there may be some intermittent data drops out due to this weather.

Friday, December 16, 2011

SDO and Comet Lovejoy

The Comet Lovejoy watch has been reported in It was pretty amazing to the see the comet emerge from behind the Sun! Perhaps we will see it in the SoHO and STEREO coronagraphs today.

Thursday, December 15, 2011

phoenix comet emerges

(Full-res Quicktime and mp4 movies)

AIA 171 20111216T004000 12s at 20111216T011640

SDO and Comet Lovejoy

Check out the SDO youtube page for lots of good movies. Check out the emergence video at under favorites.

AIA 171 20111216T004000 12s at 20111216T011620

AIA 304 20111215T233009 12s at 20111216T002650

comet lovejoy seen in 171

(Full-res Quicktime and mp4 movies)

SDO and Comet Lovejoy

Out out 171 and 193 as your first attempts. We see the the comet in 171 at 23:58:59! At 23:59:18 in 193!

The AIA team has reported seeing Comet Lovejoy coming out from behind the Sun after perihelion at about 00:41.

SDO and Comet Lovejoy

We are starting to receive the images and copy them into our directories.

SDO and Comet Lovejoy

SDO has completed the off-point maneuver and is sending the images to the ground. They should be moving thru the pipeline and available in 30 minutes at

SDO and Comet Lovejoy

Our special website for the Comet Lovejoy perihelion approach is

There are movies and a Twitter feed at the site now. Images that may contain the comet will be flowing at about 7 pm ET this evening.

SDO and Comet Lovejoy

SoHo and STEREO continue to watch Comet Lovejoy as it moves closer to the Sun and brightens. We will be running a special mode this evening to look for the Sun in the SDO instruments.

To the left is a still showing the comet headed towards the Sun. Below is a great movie from the
LASCO C3 coronagraph
showing how bright the comet is earlier today.

Wednesday, December 14, 2011

Will SDO see another comet?

We are setting up a special website to watch Comet Lovejoy pass by the Sun tomorrow night. The URL will be published tomorrow afternoon. You will be able to examine the special off-point images for signatures of the comet! The Helioviewer website is also available for making movies and looking for the comet.

Comet Lovejoy was discovered on November 27, 2011. It is a Kreutz comet, one of a family of comets that move along the same orbit---much like the meteoroids in a meteor shower. These comets come so close to the Sun that they are called sun-grazing comets.

Comet Lovejoy may become one of the brightest Kreutz comets ever seen. The latest estimates are a visible magnitude of -3. (Bright stars are magnitude -1 or dimmer.) We are making special efforts to see Comet Lovejoy this week.

Thursday night at 7:30 pm ET Comet Lovejoy will move through its closest approach to the Sun. Starting at 23:30 UTC (6:30 pm ET) Thursday we will point the SDO spacecraft a little to the left of its usual position. The images will look like this figure, where the circle is the edge of the Sun and the X’s are where we estimate the comet will be and the red arrow shows the direction the comet moves. Watching from SDO the comet goes behind at 00:22 UTC (7:22 pm ET).

All three instruments on SDO will be watching the comet. The EUV images from AIA would show the second comet seen in these ultraviolet wavelengths (the first was in July). HMI and AIA can use the comet to understand the roll of the spacecraft. EVE might see some of the atomic ions responsible for making the comet bright in the EUV.

In July we saw a Kreutz comet disappear as it passed across the face of the Sun, why does it go behind the Sun this time?

The way we see a Kruetz comet depends on where we look from. We have constructed a 3-D model of the comet orbit from blue wire and a yellow sphere. The top picture shows how the comet will move Thursday night; up from below the ecliptic, behind the Sun, and then back down, generally moving from left to right.

A view from the July position of the Earth is shown in the lower picture. The comet seen then moved up and across the face of the Sun (from right to left) because the Earth and SDO were on the other side of our orbit.

Amazing fact #1: A Kreutz comet takes 800-900 years to orbit the Sun. Because its closest approach (or perihelion) is only 0.2 solar radii above the Sun’s photosphere, each comet must travel 150-200 AU (out near Sedna) out into space before returning!

Amazing fact #2: No Kreutz comet seen by SoHO has survived perihelion passage. The comets go behind the occulting disk and do not re-appear. They probably evaporate in the fierce heat of the Sun.

Amazing fact #3: SDO is not the only satellite that will be watching Comet Lovejoy. Coronagraphs on STEREO and SOHO are already seeing the comet move toward the Sun.

It should a great show!

Monday, December 12, 2011

Sunday, December 11, 2011

Friday, December 2, 2011

SDO Weekly Report for December 2, 2011

The FOT and Science Teams monitored Reaction Wheel speeds and instrument performance as the maximum wheel speeds on wheels 3 and 4 slowly rose above 850 RPM. Wheel speed predicts have indicated that the wheel speeds should soon begin reducing on their own, but this has not yet happened. A momentum unload has been scheduled for 12/7 and will be performed if the wheel speeds have not begun to reduce on their own by then.

On 12/1 the FOT began seeing sustained winds of approximately 45 mph at both SDO1 and SDO2 antennas. They contacted SDO personnel at WSC who indicated the latest forecast for overnight was for gusts up to 85 mph. The FOT alerted SSMO management and the Mission Director (MD). A teleconference was held with the SDO Project Scientist, the FOT, the MD and SSMO management to plan for the extreme wind event. It was decided to staff overnight in the MOC and at WSC. After winds at SDO2 exceeded 65 mph for 3 samples within a 5 minute period, SDO2 was automatically braked as of 02:35 GMT on 12/2. The highest wind speed recorded at SDO2 was 74 MPH. After the winds died down, SDO2 was brought back online as of 05:50 GMT with manual workarounds. The automatic recovery of SDO2 failed due to ACA faults, apparently caused by antenna motion while it was braked. SDO1 only experienced a few wind speed readings over 65 MPH and remained on point. However, due to the very high winds, there were Ka band dropouts at SDO1 while SDO2 was braked. There were also subsequent short periods of simultaneous data loss at both SDO1 and SDO2 because of the very high winds. Preliminary estimates put the data capture for 12/2, Day Of Year 336, at 94 percent. Lessons learned from this exceptional wind event will be discussed next week.

Thursday, December 1, 2011

High Winds are Predicted at White Sands

Along with the Santa Ana winds over LA the winds at White Sands are predicted to be very high this evening (>80 mph). Here is the forecast wind pattern at 24,000 ft over the Southwest US for 7 pm MT this evening. If the winds exceed 65 mph for more than 5 minutes the SDO antennas will be stowed (pointed up and turned off). There will be no science data if the antennas are stowed.

Update 12/2/2011: The winds were quite high last night (gusts to 70 mph) and the antennas were braked several times but never stowed. Along with the high winds came large gusts that moved the antennas off the spacecraft. That means we had some data loss over night. Winds are predicted to be high today and tonight, although maybe not as high as last night.