Wednesday, January 28, 2015

EVE Cruciform Today

Today, from 1800-2252 UTC (1:00-5:52 pm ET), SDO will perform the EVE Cruciform calibration maneuver. During this time the images may be blurred.

Tomorrow is the AIA GT/PZT Calibration from 1500-1620 UTC (10:00-11:20 am ET), which should cause few problems with the SDO data.

Next Wednesday, February 4, 2015, SDO will perform two maneuvers, the EVE FOV from 1315-1557 UTC (5:15-10:57 am ET) and the HMI/AIA Flat Field from 1630-1907 UTC (11:30 am - 2:07 pm ET). During these maneuvers the images may be blurred.

Thursday, January 22, 2015

Yesterday's Maneuver and Today's Weather in Las Cruces

Yesterday at 1950 UTC (2:50 p.m. ET) SDO did Momentum Maneuver #21. Science data may not be available for 20 minutes on either side of the thruster firing.

There is heavy snow at the White Sands Complex near Las Cruces, NM. About 6" of snow has fallen so far. Snow can cause the Ka-band science downlink to fade, and it completely faded at 1815 UTC (1:15 p.m. ET) and has not yet returned at 1915 UTC (2;15 p.m. ET). The S-band link is not affected by the snow and is still being received. When the snowfall abates we will again receive the science data.

Update 23-Jan-2015: Normal science data flow was restarted at 2204 UTC yesterday (5:04 p.m. ET). Many thanks to the people who cleaned the snow off the antennas!

Tuesday, January 20, 2015

100,000,000 AIA Images!

Yesterday, January 19, 2015, at 1749 UTC (12:49 pm ET) the AIA instrument recorded its 100,000,000th image. Here it is, an AIA 193 Å image showing coronal holes in both the northern and southern hemispheres. More information, including some favorite images from team members, is available at the NASA SDO webpage.

The AIA team at LMSAL worked hard to design and build the AIA telescopes, even overcoming a delayed start way back at the beginning of the SDO project. The team continues to operate the instrument, keeping it calibrated and listing the features seen on the Sun. The HMI JSOC team at Stanford University maintains the archive that serves the images to our large and growing number of users.

Congratulations to the AIA team at LMSAL for designing, building, and running an excellent instrument for studying the Sun!

Thursday, January 15, 2015

100,000,000 on my Mind

The number 100,000,000 has been on my mind this week, especially as Monday approaches.

If I traveled 100,000,000 miles I could have gone to the Sun and been 7,000,000 miles on my way home by now.

100,000,000 seconds ago was Nov. 19, 2011, a day without great significance in my calendar.

100,000,000 people lived in the USA in 1914.

100,000,000 years ago the Sarcosuchus Imperator (left) ruled the swamps and coastlines of the world. I'm glad I never met a 8000 kg (9 ton), 12 m (40 ft) long relative of todays crocodiles!

Here's a hint. SDO started returning science data on May 1, 2010. Tune in next week to find out what's up with 100,000,000!

Wednesday, January 14, 2015

Monday, January 5, 2015

Happy Perihelion Day!

Happy Perihelion! Yesterday at 0636 UTC (1:36 am ET) the Earth was as close to the Sun as it will be in 2015. This is called perihelion. The distance change is small (about 1.67% closer at perihelion and 1.67% further away at aphelion in June), but we see the Sun as a little brighter today.

Our orbit around the Sun is almost a circle right now. That means our seasons are caused by tilt of our rotation axis. But there have been times in the past when our orbit was more of an oval. It's fun to think about what that would do to our seasons and climate. The Lensman books by E. E. Doc Smith included a nemesis with a home planet that had an extremely elliptical orbit and the bizarre evolutionary adaptations that led to.

Thursday, January 1, 2015

A Big SDO Welcome to 2015!

Welcome to 2015!

There were no fireworks on the Sun last night to welcome in the New Year. Only a few C-class flares during the last day of 2014. Instead, the Sun starts 2015 with an enormous coronal hole near the South Pole. Here is an AIA 193 Å image from January 1, 2015 showing the coronal hole as a dark region in the south.

Coronal holes are regions of the corona where the magnetic field reaches out into space rather than looping back down onto the surface. Particles moving along those magnetic fields can leave the Sun rather than being trapped near the surface. Those trapped particles can heat up and glow, giving us the lovely AIA images. In the parts of the corona where the particles leave the Sun the glow is much dimmer and the coronal hole looks dark.

Coronal holes were first seen in images taken by astronauts on board NASA’s Skylab space station in 1973 and 1974. They can be seen for a long time, although the exact shape changes all the time. The polar coronal hole can remain visible for five years or longer. Each time a coronal hole rotates by the Earth we can measure the particles flowing out of the hole as a high-speed stream, another source of Space Weather.

Charged particles in the Earth’s radiation belts are accelerated when the high-speed stream runs into the Earth’s magnetosphere. The acceleration of particles in the magnetosphere is studied by NASA’s Van Allen Storm Probe mission.

As Solar Cycle 24 fades, the number of flares each day will get smaller, but the coronal holes provide another source of Space Weather that needs to be understood and predicted.

Happy New Year!