Celebrate the Winter Solstice at 11:59 am ET today!

Today is the Winter Solstice. The length of daylight is the shortest of the year in the Northen hemisphere and the longest in the Southern. For the Northern hemisphere it corresponds to the beginning of the cold winter season while people in the Southern hemisphere are starting to enjoy their summer time weather.
The occurrence and timing of solstices was known to many early cultures, from Mesopotamia to Mesoamerica. It was a time to celebrate when the Sun stopped moving southward and began moving back to bring warm to their homes. We know that the tilt of the Earth's rotation axis causes the seasons but we continue to celebrate their changes.

Enjoy the Winter Solstice!

Momentum Management Maneuver #42, December 15

SDO executed momentum management (MM) maneuver #42 on December 15 from 1945-2015 UTC (2:45-3:15 pm ET). During an MM maneuver SDO science data may be missing or blurred. These maneuvers are needed to keep SDO accurately pointed at the Sun and taking data.

X-class flare at 1555 UTC (11:55 am ET)

Active region 12887 emitted an X-class flare today at 1555 UTC. There also appears to be a filament eruption (the precursor to a coronal mass ejection). This is the second X-class flare of Solar Cycle 25 (the first was on July 3, 2021.)

Before the flare a filament cam be seen over AR 12887 (in the blue circle).

The flare begins to brighten up at 1529 UTC.

The filament liftoff from the surface can be seen as the dark region a litle to the left of the flare in the third image.

The flare continues to brighten until its peak flux. Check out the flare in the Browse AIA/HMI Images at the SDO website.
Solar Cycle 25 is alive and well!

October 2021 Instrument Calibration Maneuvers have Finished

The October 2021 Instrument Calibration maneuvers have finished. During an instrument calibration maneuver SDO science data may be missing, blurry, or misaligned. The first two cannot be corrected but roll angle is no longer seen as a rotation of the solar image.

• 13 Oct 2021: EVE Cruciform, 1400–1852 UTC (10:00 am - 2:52 pm ET)
• 20 Oct 2021: HMI Roll Maneuver, 1400-2040 UTC (10:00 am - 4:40 pm ET)
• 27 Oct 2021: EVE FOV and HMI/AIA Flatfield Calibrations (EVE FOV @ 1315 UTC; HMI/AIA Flatfield @ 1630 UTC)

The next set of calibration maneuvers will be in January 2022 (EVE Cruciform, EVE FOV, and HMI/AIA Flatfield) and April 2022 (HMI Roll).

Momentum Management Maneuver #41 today

SDO will execute momentum management (MM) maneuver #41 today from 1820-1840 UTC (2:20-2:40 pm ET). During an MM maneuver SDO science data may be missing or blurred. These maneuvers are needed to keep SDO accurately pointed at the Sun and taking data.

Congratulations to the EVE Team!

NASA 36.353 sounding rocket flight to calibrate SDO EVE and several other satellite instruments was a great success. Hre's the proof, exposures from both the MEGS-A and MEGS-B CCDs in the calibration EVE. The top image is from the MEGS-A CCD with MEGS-A1 spectrum on top and MEGS-A2 spectrum and MEGS-SAM X-ray image on the bottom. The bottom CCD image is the MEGS-B spectrum that goes diagonally across the CCD. The bright (yellow and red) vertical stripes are the spectral lines of the Sun that EVE studies. Just seeing these spectral lines means our Sun has a magnetic field. Without the magnetic field this part of the spectrum would be empty.

I can't wait to see the movie.

Congratulations to the EVE for a successful flight!

EVE Calibration Rocket Flies over WSMR Today

Today the EVE Calibration Rocket will fly above White Sands Missile Range (WSMR) near Las Cruces, NM. The launch window opens at 11:25 am MT (1:25 pm ET) and closes at 12:05 pm MT (2:05 pm ET). The EVE team is watching the Sun. The goal is to measure the quiet Sun and any significant flare will delay the launch until the effects of the flare fade. After parachuting to the ground, Rocket EVE will be re-calibrated at NIST's SURF in Maryland.

These calibration rockets are needed to track the changes in the EVE and AIA instruments that have been in orbit for over 11 years. Instruments that measure the extreme ultraviolet are extremely sensitive to contamination. Even small amounts of hydrocarbons (such as Teflon) landing on the CCDs inside the instruments can reduce the amount of light reaching the pixels. Comparing the data from the instruments in space with the data from the “clean” calibration instrument gives the correction factor we need.

Check out the LASP news release for more information.

Here's to a great launch and successful recovery!