Archive for category General
The Sun has many different features and events of great scientific interest. It’s useful to be able to catalog those features and measure their properties. By doing so, we can build up more knowledge about the Sun.
The Heliophysics Event Knowledgebase (HEK) is one such catalog. The HEK collects and stores information about many different types of solar feature – active regions, flares, etc, from many different sources around the world. Each solar feature and event can be detected in different ways. Some features and events are detected by people looking at the data, and some are detected by specialized computer vision algorithms.
We’ve taken the information in the HEK and designed a simple interface to allow you to find out what features and events occurred on the Sun at any given time. We’ve organized the information in the HEK by feature/event. You may need to reload helioviewer.org to get the latest version which includes the HEK.
The numbers at the end of each line tell you the total number of features/events of each type on the Sun at that time. You can select any combination of features and events you want (green tick marks), or you can select none. If you’ve selected a particular type of feature/event but the text is faded out, this means that there are none of those particular feature/events at the time you’ve requested. If you browse forward and backwards and time and those feature/events are in the HEK, helioviewer.org will display them.
We then break down the total number of features/events by feature recognition method. We do this because different feature recognition methods can give different results for the same feature/event type. You can select any combination of the available feature recognition methods, or you can select none. For example, the active regions on the Sun at this time were detected using two different feature recognition methods:
Here’s a typical view of some AIA 304 data with the HEK features and events overplotted.
Each of the marker pins corresponds to the feature/event detected by a feature recognition method. Clicking on them pulls up much more information on each individual event. Each of the marker pins also has a small label attached to it with an important piece of information concerning that feature/event. We’ve also extended the movie and screenshot capability so that your selected feature/event markers and labels appear in any movies and screenshots you make.
Finally, in the bottom left-hand corner of the viewer window you’ll see a small image of the Earth. This is the size of the Earth on the same scale as the solar and heliospheric images. This also appears in movies and screenshots of the Sun. Full information on using helioviewer.org can be found by clicking the help link at the bottom of the helioviewer.org webpage.
The HEK is the result of much work by many different people around the world. We are happy to be able to present data from this great solar and heliospheric resource in Helioviewer.org.
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.
Maintenance operations on the Helioviewer server are now complete, ahead of schedule. All Helioviewer services should be up and running as normal. We thank you for your patience in the last three days while our maintenance operations were ongoing. Please contact us if you notice a departure from normal services.
Today’s announced maintenance has been postponed until Friday 1st February. Helioviewer services will be brought down around 1600-1700 UT and will be brought back up no later than 2200 UT. We apologize for any inconvenience this may cause.
All Helioviewer services (helioviewer.org, JHelioviewer and the embed functionality) will be temporarily suspended today (30 January 2013) to allow for maintenance of our server. We anticipate that services will be suspended at around or before 1700 UT and will resume again at around 2230 UT at the latest (could be much earlier). We apologize for any inconvenience this may cause.
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.
A total solar eclipse will be visible in the Southern Hemisphere on November 13.
Eclipse first contact begins at approximately 20:36 UT on November 13 and continues until approximately 23:48 UT on November 13. Live streaming of the eclipse is available at http://www.ustream.tv/cairnseclipse2012. Please go to
for many more details concerning this eclipse. An interactive map is available here.
Hurricane Sandy is currently approaching the East Coast of the United States. Winds from the hurricane are expected to cause widespread power outages in the next 48 hours (Oct 29-30). Since an unplanned power outage to a server can cause severe damage, we are taking the precautionary measure of shutting down the Helioviewer server. The server will shut down in the next hour. We expect to be back online by Wednesday 31st October EST at the latest, contingent on the weather and the availability of power. We apologize for the inconvenience this will cause.
Helioviewer.org and JHelioviewer are both back online after last week’s outage.
The downtime was caused by a problem encountered while expanding our storage capacity, which has since been fixed.
We are currently in the process of restoring images from some earlier years and as a result certain images may not be accessible over the next couple days.
We apologize for any inconvenience this may cause.