NEW: Solar features and events from the Heliophysics Event Knowledgebase

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 to get the latest version which includes the HEK.

HV intro: Screenshot from 2013-07-16 10:18:37

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, 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:

HV Intro: Screenshot from 2013-07-16 10:19:05

The numbers at the end of each line tell you how many active regions were detected by SPoCA (a computer vision algorithm) and the NOAA SWPC Observer (people looking at the data).

Here’s a typical view of some AIA 304 data with the HEK features and events overplotted.

HV Intro: Screenshot from 2013-07-16 10:29:31

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 can be found by clicking the help link at the bottom of the 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

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  1. #1 by Lily on July 18, 2013 - 3:12 am

    Wow, I can’t wait to use it. Thank you so much for all the hard work.

    • #2 by jack on July 19, 2013 - 6:10 pm

      Thank you – we hope you enjoy it! Please let us know if you come across any bugs, or have any ideas for new features.

      • #3 by Lily on December 20, 2013 - 2:30 am

        HI Jack,

        I have been experiencing problems with both helioviewer and JHelioviewer. Helioviewer not able to generate movies, and error message “An error occurred when opening the remote file! Error in the server communication: Broken pipe” on JHelioviewer. I was wondering whether this is solely my problems because I can see others sharing their movies.

        I am using Safari, I have tried Firefox, the same problem occurred.

    • #4 by Arya on August 5, 2013 - 5:27 am

      What is the time-scale being shown here? That is, at what frame rate is SOHO capturing ieamgs (f per sec, per min, per hour ) ?Awesome stuff, regardless. Thanks so much for consistently sharing so much incredible imagery from all of these missions/instruments.

      • #5 by jack on August 14, 2013 - 1:02 pm

        We provide images from 4 instruments from SOHO – EIT, LASCO-C2, LASCO-C3 and MDI. MDI was switched off in 2010 and so it is not taking any current images. The other three instruments are still operating. EIT now takes eight images a day. LASCO-C2 takes an image once every 12 minutes, and LASCO-C3 takes an image once every 12-24 minutes.

        We hope you continue to enjoy the imagery from these and other instruments!

  2. #6 by Janssens on July 18, 2013 - 9:32 pm


    Is it possible to turn off/on the earth size icon? It is useful, but most of the time not wanted.

    Coronal hole areas are not available for SOHO, or time dependant? Are these CH areas apparent or corrected (for distance to centre)?

    This is going to be fun to try out all these new features. A great improvement! Job well done!

    • #7 by jack on July 19, 2013 - 2:25 pm

      At the moment it is not possible to switch off the Earth size icon. I think this is a good idea, however, and I will post it as a feature request. We will implement this as part of our larger plan to allow users to cycle through a variety of size indicators, probably in much the same way as pressing the ‘m’ key allows you to cycle through a variety of co-ordinate systems. Other size indicators we will use are fractions/multiples of a solar radius and megameters (1000km = 1 Mm).

      The HEK does store some measurements of coronal holes in the SOHO era. For example,,AIA,AIA,171,1,100%5D,%5BSOHO,LASCO,C2,white-light,1,100%5D

      The coronal holes noted here are determined using the “LMSAL forecaster + SSW PFSS package” feature recognition method. Coronal holes are found by a Lockheed Martin forecaster using the Solarsoft package “PFSS” to extrapolate observations of the Sun’s magnetic field out into the heliosphere. This detection is based on modeling the Sun’s magnetic field, and not on observing a dark region in a coronal temperature bandpass (which is what the SPoCA algorithm does). Note also that many of these coronal hole detections have a start time identical to the end time. This means that you will only see them in if you know what time these coronal holes were determined at and if you point directly at that time. You can get these times from looking at iSolSearch.

      Finally, for details on the coronal hole measurements such as correction for Earth-Sun distance, please contact the person responsible for the feature recognition method. For SPoCA detections, please contact veronique.delouille[at] and for “LMSAL forecaster + SSW PFSS package” please contact derosa[at] Contact details regarding HEK entries can usually be found by clicking on the feature/event marker, then clicking on “View HEK data” and selecting the “Observation” tab in the pop-up window. Look for “frm_contact” to get an email address.

      Hope this helps! Let me know if you have any problems.

    • #8 by jack on July 30, 2013 - 9:08 pm

      We just updated the website to allow the Earth size icon to be switched off, and for it to be draggable in movies and screenshots. Hope this helps!

  3. #9 by Sun Whisperer on July 28, 2013 - 11:40 pm

    Thank you so much for this program / website and all of the improvements. It is an amazing and useful application. Keep up the great work!

  4. #10 by Cliff on November 4, 2013 - 2:12 pm

    Why doesn’t the HEK function work all the time. Sometimes I get it and sometimes no matter what I do nothing comes up.

    • #11 by jack on November 26, 2013 - 3:08 pm

      What browser and operating system are you using?


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