Archive for June, 2011
We apologize for the lack of new images from AIA. This is due to issues outwith our control. We create the images you see from AIA level 1.5 data products (the number refers to the degree of image calibration, etc., that has been applied to the raw data) that are processed at SDO Joint Science Operations Center. As you can see, those data appear to be lagging at the moment. As soon as the data returns, Helioviewer will automatically generate images and make them available.
Some of you may have noticed that helioviewer.org was not displaying recent AIA or HMI images in the last 24 hours. This was due to a glitch in the processing pipeline, and we apologize for this. The issue has been resolved and newer images are now coming online. We expect to be caught up within the next few hours. If you spot any problems, please let us know.
Helioviewer and YouTube user otraLoly spotted this interesting active region earlier on today.
Right at the very start you can see that loops on the southern side of the active region appear to contract (a CME and a prominence eruption are occuring). As the event progresses, you’ll notice that two dark areas appear in the coronal moss, outlined by some very bright, and small scale emission, which end up as loop footpoints to the subsequent loop brightening that occurs. This event is interesting for the detail it is possible to see in AIA, particularly in the brightening of the loop footpoints before the main bright loop occurs. Thanks to user otraLoly for sharing this video with users of helioviewer.org!
Dan Pendick recently posted an excellent series of articles about the Helioviewer Project on his blog, Geeked on Goddard. In five short articles Dan describes many of the different parts of the project, including Helioviewer.org and JHelioviewer. He also discusses some of the technologies that have made all of this possible. If you are interested in learning more about the project and how it all works, you should definitely check out the articles. Also, if you are a science/tech enthusiast I would highly recommend subscribing to Dan’s blog where you can learn more about some of the other cool projects that call the NASA Goddard Spaceflight Center their home.
Post 1 of 5: Explore the sun on your desktop with Helioviewer
Post 2 of 5: Getting Started with Helioviewer.org
Post 3 of 5: Explore the sun in depth with JHelioviewer
Post 4 of 5: How it works: building the Helioviewer “back end” with JPEG2000
Post 5 of 5: Helioviewer’s future: an Internet for solar image data
We are pleased to announce that the most recent, high quality STEREO images are now available on helioviewer.org.
First off, there are two spacecraft, called STEREO-A and STEREO-B. Both spacecraft orbit the Sun at roughly 1 AU (astronomical unit), or about as far away from Sun as the Earth is. However, STEREO-A is moving ahead of the Earth in its orbit, and STEREO-B is drifting behind the Earth in its orbit. This means that each STEREO spacecraft sees different parts of the Sun, parts that we can’t see from Earth. STEREO-B sees features on the Sun that we eventually see in SDO and SOHO, and STEREO-A allows us to see the continuing evolution of features that we did see in SDO and SOHO.
This plot shows where each spacecraft is now:
As you can see, they are quite far away from the Earth. This puts some operational constraints on each spacecraft that means we get high-quality images two days after they were taken. These are the data we are making available today; images from June 1st 2011, up to the most recently available data will be available initially. We ask for your patience, as we are uploading these images right now. Over the course of the next few weeks we will be making images from earlier in the mission available so that you can explore the Sun from many different angles over the past 4 1/2 years.
The benefit of seeing the Sun from many different angles is apparent when you look at the following three videos of the prominence eruption of June 7, 2011. The first one consists of images from SDO-AIA and SOHO-LASCO
We hope you enjoy these new images! As ever, please let us know if you spot any problems.
Although Tuesday’s eruption was certainly a wonderful sight, it isn’t the first time that SOHO and SDO were able to capture some really cool events in action.
Here are some videos of other events that from earlier this year, starting with a few of the videos from this week’s eruption:
Note: Many of the videos above are from the YouTube channel “Helioviewer”. As of this week we are moving to a new location! If you want to see new videos that we post, subscribe instead to HelioviewerScience.
Well, we were hoping it wouldn’t come to this, but unfortunately we had to reset the movie queue this morning, deleting many requests which were made during the last couple days. The reason for the reset is that our server was overwhelmed with requests, to the point where new requests had estimated wait times in numbers of days, which is unreasonable. We looked into many different options, and tried some (including reducing the size of the movies made), but nothing was able to completely solve our problems: the time it would have taken to completely catch-up would have meant that even if other new exciting solar events were to occur, videos of those events would not be processed until days later!
In the future we will try and take measures to keep this from happening again. The last couple of days have made us look at the services we provide in a whole new way, thanks to the huge interest from you, our users, and we are grateful for that. We are constrained by our resources, so we may not be able to process many more movies each minute any time soon, but what we can do is make it easier for users to find other movies that are out there that have already been made. Thousands of movies have been made by users on Helioviewer.org, but right now there is no simple way to search through those movies and find the ones you are interested in. Further, we will also take some measures to make the users more aware of what the current wait time is before they submit a movie request, and also provide them with an option to cancel the request if they decide they do not want to wait for the movie. All of this will make it easier for you to get to the movies you want.
We apologize to all of the users who have queued movies during the last couple days that did not get processed. If you are still interested in making a movies please go ahead and queue it up again. Hopefully we will not have to take such extreme measures again. Thanks to you all for your patience.
Yesterday’s spectacular eruptive event was just one example of the amazing phenomena on the Sun and the inner heliosphere. Stuff is going on all the time, like this coronal mass ejection seen by the STEREO mission
or this intriguing prominence (the dark wispy shape close to the edge of the Sun’s disk) evolution, spotted just a couple of days ago by the Solar Dynamics Observatory:
We can even sometimes see comets when we look at the Sun:
In fact, the SOHO spacecraft has discovered more comets than any other mission. This particular comet was spotted by an astronomy student, Michal Kusiak of Krakow, Poland.
If you want to know more about the Sun and the inner heliosphere, we suggest going over to The Sun Today. There you can find out more about recent solar events, and what caused them. Got a question about the Sun? Then ask a solar physicist over at the The Sun Today.
In response to the huge demand resulting from yesterday’s spectacular eruption, we are going to temporarily decrease the maximum size of the movies created on Helioviewer.org.
When you request a movie on Helioviewer.org we attempt to use as many images as are available for the requested time period, within a specified limit. Normally that limit is 300 images. For a single-layer movie this meant that the movie would be created using about 300 images. For multi-layer movies, the number of images allowed is divided by the number of layers included or order to deal with the increased strain. For instance, if you requested a two-layer movie (e.g. AIA 304 and LASCO C2), the limit would go become 300 / 2 = 150 images. Similarly, for a three-layer movie the limit would be 300 / 3 = 100 images. All of this is simply to make it possible to create movies in a reasonable amount of time, within the constraints of the server Helioviewer.org runs on.
In order for us to be able to process the large amount of movie requests waiting to be processed (currently about 3000), we are going to temporarily decrease the maximum movie image limit from 300 to 150. In order to keep the frame-rate high, we will also decrease the default movie duration by a proportionate amount: instead of each movie being 20 seconds long, movies will be 10 seconds long instead. So basically, if you either requested a movie during the past 24 hours, or request one sometime during the next several days, it will likely be half as long, and include half as many images as usual. Once movie demand returns to a more sustainable level and we have caught up with the current queue of movies these limits will be returned to their normal values so users can continue to make the high-quality movies they are used to.
Thanks everyone for your patience.
Update June 09, 2011: We have decreased the image limit (from 150 to 100) and movie duration (from 10s to 6.6s) once more to account for the continued high-demand. Once things slow down a bit we’ll increase the limit first to 150, then back to 300.
As you may have already noticed if you tried to make a movie this afternoon, the estimated wait time for new movies requests is currently very long due to the exciting eruption we saw this morning. Usually when you request a movie it will be created within a couple minutes. Right now, however, the queue time is in the hours range.
All movie requests will be handled in the order they are received, so you are welcome to queue up a video and check back later in the day to see if the video is available. Another option though would be to check out some of the excellent videos made by other Helioviewer.org users. You can use the arrow buttons or mouse-wheel to scroll down the list of shared videos on bottom-right of the page and see what other people have made.
These videos show some of the larger scale effects of flares on the Sun. In the video, you can see two big eruptions approximately 10 and 17 seconds into the video, from the active region in the lower left.
But look more closely – can you see a wave of coming out of each of these explosions? They are faint, and can be difficult to see, but they are there. These are examples of EIT waves, so called because they were first seen in the SOHO–EIT instrument. These waves are thought to be examples of magnetohydrodynamic waves that propagate in the corona. They are truly large waves; for comparison, the radius of the Earth is about 1/100th that of the Sun. By studying these waves we can learn more about the structure and properties of the solar corona. There is also some evidence that these waves have ‘knock-on’ effects on other parts of the Sun, perhaps causing other events at parts distant from the original explosion. Look at the video – what do you think?