The material travels in to the field of view from its launch location, which can be seen in STEREO-B EUVI images. If you go to STEREO latest image selector and select ‘Behind EUVI 195′, pick a resolution of 512 x 512, type in a start and end date of 20120202, and select ‘Slideshow’, you get an animation of the event as seen from STEREO-B. There is a filament eruption on the upper left of the disk (it is hard to spot) which is the same material seen in the AIA 304 movie above:

and a flare in more or less the same area of the Sun – look for the very bright patch at the limb of the Sun at the upper left of the disk.

Thanks to goggog67 for spotting this event and sharing it with us!

The filament is the large dark straggly line of material in the upper left of the movie. Click here to see the movie in helioviewer.org.

Filaments are cool strands of material about 100 times cooler than the surrounding plasma, and are supported by magnetic fields. They can lie suspended but cool in the hot solar atmosphere for weeks, and then erupt in a matter of minutes, causing coronal mass ejections. It should be rotating into the SDO field of view in the next couple of days. If you are on Facebook, The Sun Today has a great post about this filament. Let’s see what happens!

The STEREO (Solar TErrestrial RElations Observatory) mission is very different from the other missions (Solar Dynamics Observatory and SOHO) we feature 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.

We hope to have a stream of the very latest STEREO images very soon. Watch this space!