Looking for Comet C/2024 S1 (ATLAS)

SDO images look partial today as we are off-pointed to look for the tail of Comet C/2025 S1 (ATLAS) as it goes by perihelion. This is a Kreutz comet with a perihelion distance of 1.7 Rsun (0.7 Rsun above the surface of the Sun.) The perihelion time as seen at Earth is about 11:45 UTC (7:45 UTC). We will hold the offpoint until 12:05 UTC and then return to normal pointing. HMI magnetograms and Dopplergrams are not available during the offpoint.

Network Outage Causes Data Problems

A cable cut in New Mexico is causing some of the SDO telemetry to be delayed to the science teams. As a result, the teams do not know the roll angle of SDO and the images appear to be rotating as we execute the HMI Roll Calibration today between 1500 and 2140 UTC (11:00 am - 5:40 pm ET). The rotation angle will be provided in due course and the science data will have the information to be correctly oriented with solar North up. Once the maneuver is finished the images will again be correctly oriented.

Celebrate Solstice 2024 with a Solar Fireworks Show!

Today is the Summer Solstice, the longest day in the Northern hemisphere and the shortest day in the Southern. That officially happens at 20:50 UTC (4:50 pm ET). This solstice is the first day of summer in the USA.

But it has nothing to do with the Sun. The solstice is caused by the tilt of the Earth’s rotation axis to its orbit. On the other hand, we are in the maximum of Solar Cycle 25. Active region 13664 was an excellent example of how an active region should behave during a solar maximum. During the 16 days that AR 13664 was visible from the Earth in May, it produced 99 flares, including 12 X-class flares.

I produced a video of AR 13664 to celebrate the solstice. I downloaded three-color AIA images from the SDO website AIA and GOES XRS fluxes from the GOES website for days between 01 May 2024 and 16 May 2024. After removing the blank and offset images taken during an EVE cruciform, there were 1522 valid images in those 16 days (99% of the possible 15-min images). The XRS flux had 21616 points that were greater than zero.

Using the JythonMusic synthesizer, the XRS fluxes were converted to MIDI percussion sounds and then into a mp4 file. There’s a lot of different drums and cymbals in the soundtrack. XRS fluxes below a C-class flare were made into rests. When the video is quiet the Sun’s activity level is low.

The AIA images and audio file were combined to give the Solstice Celebration Video shown here.

The video starts with sporadic flares and some visible activity. Once AR 13664 starts generating flares the sound and images quickly start to resemble a fireworks finale! As AR 13664 rotates out of view the activity level drops, even though new active regions have appeared. You can also see a few non-solar things, such as the apparent rotation during a calibration roll maneuver. The flare sounds and flares in the images are not exactly in synch as the images are not frequent enough.

The solar fireworks were only the beginning. The largest geomagnetic storm in over 20 years took place on 11 May 2024. It's nice to see some geomagnetic activity after the storm-poor Solar Cycle 24. Large solar and geomagnetic activity makes it more difficult to track satellites in low-Earth orbit to keep them from colliding but that’s why we study the Sun.

AR 13664 was a fascinating feature of Solar Cycle 25!

Eclipse Day Transit was not as Exciting as the Total Solar Eclipse

On April 8, 2024, people along a path from Mexico thru the USA and into Canada were treated to a total solar eclipse. SDO waited until much later in the day (actiually the next day in the UT timezone) and saw this glancing lunar transit.

The Moon covered about 5% of the solar disk at 09-Apr-2024, 03:36 UTC (08-Apr-2024, 11:36 ET). It is an interesting problem to understand why the motion of SDO in its geosynchronous orbit above the Mountain timezone against the lunar velocity later in the day allowed the transit many hours after the eclipse on the ground. Perhaps the next post will explore those details.

You should check out the spectacular photos of the total solar eclipse. There was at least one prominence visible to my eyes on the limb.

Spring 2024 Calibration Maneuvers Begin Today

Today SDO will execute the EVE Field of View (at 1315 UTC, 9:15 am ET) and the HMI/AIA Flatfield (at 1630 UTC, 12:30 pm ET) calibration maneuvers. During these maneuvers SDO science data may be missing or blurred.

Momentum Management Maneuver (Delta-H) #49 today

SDO will execute Momentum Management Maneuver (Delta-H) #49 today. Between 1830 UTC (2:30 pm ET) and 1910 UTC (3:10 pm ET) science data may be missing or blurred.

09 April 2024 Lunar Transit (08 April for North America)

On April 8, 2024, a large swath of North America will enjoy a Total Solar Eclipse from Mazatlán up through Texas to Maine and the Maritime Provinces of Canada. Although those along the path of totality will enjoy a beautiful view of the solar corona, SDO will only see a short, almost glancing transit of the Moon across the Sun long after the TSE ends. The SDO transit starts at 03:29 UTC on 9 Apr 2024 (10:29 pm EDT on 8 Apr 2024), 7 hours after the TSE ends on the ground.

Here is a movie from the SDO Flight Dynamics Team showing the transit.

The transit will only cover 5% of the solar disk.

If you live in Mexico, USA, or Eastern Canada, please go watch the Total Solar Eclispe. They are a wonderful way to see the Sun in a different light.