This is the Solar Dynamics Observatory Mission blog. It will consist of mission status, news, and event updates.
Next week SDO will perform the EVE cruciform maneuver on Wednesday, April 18, starting at 1430 UTC (10:30 am ET). Once again, SDO will roll to normal pointing before the test and roll 180° after the test.
The arrows in the magnetogram point to magnetic fields that follow Hale’s law for Solar Cycle 24. The blue arrows point to areas that show the pattern for the northern hemisphere and the single red arrow the southern. Even the broad areas of magnetic field in the northern hemisphere follow this pattern.
The magnetic field in the patch of magnetic field in the blue circle has the black leading the white — a sign that it is related to Solar Cycle 25, especially because it is at higher latitudes than most of the sunspots seen around this time. This is another pattern in sunspots. They tend to appear at higher latitudes early in a cycle and appear at ever-lower latitudes as the cycle progresses.
The first observer notified other members of USET and one of them went and looked at the Sun. There was a small sunspot where the patch of magnetic field was seen. It was assigned the number AR 12620. It is the small black dot above the label in the orange HMI continuum image. Only one of the four other patches of magnetic field in the magnetogram was also visible as a sunspot (AR 12619). Looks like we have a winner!
Each Solar Cycle overlaps with the ones before and after. We study this overlap in our quest to understand the solar magnetic field and the dynamo that creates it. Our modern data, especially the full-disk magnetograms, makes looking for these overlapping regions a little easier.
As solar minimum draws near, we will see fewer sunspots but more and more of them will have the properties that put them into Solar Cycle 25. Eventually, solar minimum will be reached and after that sunspots associated with Solar Cycle 25 will become the majority. That should happen in 2020.
It is good to see that solar activity will continue to fascinate us in Solar Cycle 25.
As you can see in the picture, the FOT is using Camilla as a reminder what roll angle SDO is at. Currently at 153.7°, tomorrow SDO will roll to 180°. The test will end on April 25 at 1900 UTC (3 pm ET).
As the test progresses, the software to correct the orientation of the near-realtime images continues to be improved. By the end of the test all of the images will be correct!
During the test the roll angle of SDO will vary from 0 to 180 degrees. Near-realtime images from SDO may appear with the incorrect position angle, similar to what happens during an instrument calibration. To ensure you have correctly aligned science data, please use the exported images from the JSOC or the SSW IDL routines aia_prep.pro and hmi_prep.pro. If you use other software for data analysis, make sure you properly account for the value of the CROT2 when preparing the data.
Remember: This is only a Test!"
Enjoy Π Day!
Station-keeping maneuvers are performed to keep SDO inside of its box in the geostationary belt. Even though SDO’s orbit is inclined 28° to the equator (where geostationary satellites orbit), we pass through the geostationary belt twice each day. We must stay inside our longitude box to avoid interfering with our neighbors. SK maneuvers happen about twice each year.
SDO still produces high quality data of the Sun every day. Even Solar Cycle 24 fades from view, we are watching the polar region magnetic fields grow. Large coronal holes can often be seen in the AIA coronal images. Solar Cycle 25 will soon be visible. SDO is ready!