Archive for category AIA
We’ve reached an amazing milestone thanks to you, our users. Users of Helioviewer.org and Jhelioviewer have created over one million movies since we started counting them in February 2011. This represents an incredible amount of interest from you – our users – in the Sun and the inner heliosphere. We’d like to thank you for your continued interest in exploring our star and its influence in interplanetary space.
The millionth movie was of one hour’s worth of data from the Atmospheric Imaging Assembly (AIA) on SDO, focusing on this small but fast ejection from the Sun.
This led to a faint and extended coronal mass ejection seen in LASCO C2.
The coronal mass ejection was noticed in many different online catalogs of features and events in the Sun, but the original eruption was not. This is an example of how users are finding events on the Sun which are sometimes overlooked.
Just before the millionth movie, someone made this movie of one week of solar activity. This movie shows many different flares and eruptions of all sizes over the course of a week. Also, about 10 seconds into the movie (beginning around 2013-04-17 16:30 UT), you can see that black edges appear on all sides of the field of view. This is caused by the SDO spacecraft pointing slightly away from the center of the Sun for short periods of time. SDO does this to enable measurements of the AIA and HMI detectors. These measurements are a regular and normal part of running the AIA and HMI instruments, and allow us to keep track of the degradation of the detectors.
We’ll be adding new functionality and datasets to the Helioviwer Project in the next few months. We are committed to making it easy for everyone everywhere to explore the Sun and inner heliosphere, in the way you want. We hope that you continue to enjoy using Helioviewer.org and Jhelioviewer. If you have any ideas on how we can improve our service, please let us know.
Finally we’d like to thank the many NASA, ESA and JAXA funded organizations that have made the Helioviewer Project possible.
We are currently experiencing some technical difficulties with our main Helioviewer server. While we work on fixing it, we have moved all helioviewer.org services over to our backup server. All normal helioviewer.org services should be operating nominally. Please contact us if you notice anything amiss with helioviewer.org. JHelioviewer services are currently not operational, but we hope to have these up and running as soon as possible. Near real-time AIA and HMI images should be available as usual; streams of images from SOHO, STEREO and PROBA2 should be back to near real-time within 24 hours.
We apologize for the interruption to Helioviewer services, and we thank you for your patience.
From today’s SDO blog entry:
Today, starting at 1315 UTC (8:15 am ET), SDO will execute the EVE Field of View maneuver followed by the HMI/AIA Flatfield at 1630 UTC (11:30 am ET). During these maneuvers the science data will be interrupted. These maneuvers and last weeks’ Delta-H thruster firing were flipped in the schedule published earlier.
Instruments can degrade in the harsh environment of space, and so it is important to calibrate at regular intervals to make sure that we have the best data available at all times. SDO therefore occasionally makes special maneuvers that enable the measurements to be made that can be used to help calibrate the instruments onboard. Whilst these maneuvers are going on, some of the AIA and SDO images may look unusual.
SDO has three instruments onboard: AIA, HMI and the Extreme Ultraviolet Experiment, EVE. The EVE instrument is designed to measure the solar extreme ultraviolet (EUV) irradiance. The EUV radiation includes the 0.1-105 nm range, which provides the majority of the energy for heating Earth’s thermosphere and creating Earth’s ionosphere (charged plasma). The majority of EVE data are time-series of measurements of the spectral content of solar extreme ultraviolet irradiance, although some low spatial resolution x-ray images are also taken by the EVE Solar Aspect Monitor (SAM) instrument (see the example below). EVE gives us lots of information on the spectral content of the Sun’s radiation changes with time, which is very important for understanding the Earth-Sun connection.
As the movie progresses, you see a small eruption take place. As the eruption starts, you can clearly see the southern base of the loop displace. The loop appears to be released in some way, which shakes the whole loop along its entire length. This event is a great example of a transverse coronal loop oscillation. These were first observed by the Transition Region and Coronal Explorer (TRACE) in 1998. Since these initial observations, many more examples have been observed, by both TRACE and AIA. The mechanism of the excitation of these waves remains hidden, but it can be connected with a blast wave generated in a flare epicentre. For scale, the Earth is roughly the same size as the Helioviewer logo in the bottom right hand corner of the movie.
although it is much more difficult to see in the AIA 193 Angstrom channel compared to the AIA 171 Angstrom channedl(the dark wavy material you see are motions in a prominence, not the same as the coronal loop oscillation).
Observations of coronal loop oscillations, coupled with a theoretical understanding of how these oscillations behave in the coronal plasma has lead to a new field of study called coronal seismology. Coronal seismology is analogous to seismology on Earth. Seismology is the study of earthquakes and the propagation of waves arising from earthquakes, and can be used to infer properties of the structure of the Earth. Similarly, coronal seismology is used to measure properties of the Sun’s coronal plasma. Using coronal seismology, we can derive the density and magnetic field of the coronal plasma, measurements that are difficult make in other ways.
SDO AIA and HMI images are currently lagging behing real time by about 18 – 22 hours. This is due to some necessary hardware upgrades in the processing pipeline that have interrupted the flow of images. The availability of LASCO, EIT, COR1, COR2, EUVI and SWAP images is unaffected by these hardware upgrades. We expect that the lag in SDO AIA and HMI images compared to real time will be caught up in the next few hours. We apologize for the interruption in availability of near real time AIA and HMI images.
Here are some of the many excellent videos made by Helioviewer.org users of the Transit of Venus seen by AIA…
A new version of JHelioviewer is available for download. What’s new? This update release contains improved movie export functionality, an updated LASCO C2 coronagraph mask, the new SDO Cutout Service plug-in plus various bug fixes.
The new movie export menu makes it easier to set the exact scaling of the area you are interested in, and the processing itself is now performed on the graphics card using OpenGL:
The SDO Cutout Service plug-in allows you to request science-quality image data from the SDO/AIA and HMI instruments for the region of interest and time range selected in JHelioviewer:
As you may have noticed, we are currently experiencing a lag in the availability of SDO images. The lag is happening upstream of Helioviewer. The Helioviewer Project provides images of scientific data. The science data is beamed down from the spacecraft , to a dedicated ground station (as outlined here) in New Mexico. The packets of data are first re-assembled to form the raw science data, and then have some corrections applied to yield data suitable for science applications. Data is constantly streaming off the spacecraft and being processed through this pipeline, which involves many different locations and institutions.
One of those science applications is visualization of the data. The Helioviewer Project takes that science data and converts those data to JPEG2000 images, which we then make available via www.helioviewer.org and www.jhelioviewer.org. We have to have the science data available to make the JPEG2000 images.
As soon as new SDO-AIA and HMI images become available, we will make them available to you. We regret the interruption to the stream of SDO data. Other data-sets are unaffected, and are available as usual.
What happened? Well, there was an eruption on the back side of the Sun, that caused a propagating disturbance in the solar atmosphere. that appears to have triggered a prominence lift-off on the front-side of the Sun. This is a great example of how the high cadence, continuous observations from Solar Dynamics Observatory give us a much better view of how distant parts of the Sun can physically influence each other. We liked this event so much we made and uploaded some movies of our own. The lower cadence of these movies allows you to see the swaying of coronal material in response to the disturbance from the initial eruption.
A colleague who works with LASCO data yesterday found this lovely spiralling eruption close to the south pole.
It’s a great example of how the magnetic field can influence the dynamics of erupting plasma. The eruption starts around 00:13 in the above video.