Astounding Filament

Longest Filament Yet!

During five years of solar observation I've never seen a filament as long as the one recently spread across the Sun! This astounding cloud of hot plasma ran like a river: springing up near a sunspot and winding across almost an entire solar diameter on the bottom of the Sun! Here's a 32-image imperfect mosaic showing what it looked like on the afternoon of February 11th:

There were about ten filaments present including the enormous one. Only three modest sunspots added to the scene. The inverted version highlights the filaments.

The next two images are from NASA's orbiting Solar Dynamics Observatory. They were taken at about the same time as my images. My images show the solar chromosphere in the 6563-Angstrom visible red light of excited hydrogen atoms. The NASA images show the solar corona, above the chromosphere, in the 193-Angstrom extreme ultraviolet light of 11-times ionized iron atoms. The first image shows that the long giant filament also exists in the corona. The dark area in the center is a coronal hole where solar wind shoots out freely into space towards Earth.

The next NASA image shows magnetic field lines superimposed on the previous image. Whoa! You can see how the long filament runs underneath a tunnel of magnetic field loops. Amazing!

After my last observing session on February 4th I watched online daily as the huge filament gradually revealed itself. The full length eventually came into view as the Sun rotated for seven cloudy days. Finally, on February 11th, the afternoon sky cleared. The temperature was in the low 40's, normally a bit too uncomfortable for pleasant observing, but this unique feature lured me outside. The telescope mount functioned properly, and I captured images from 2:14pm EST to 3:25pm EST. Unfortunately, the seeing was not very good. Close examination of the first mosaic above shows slightly blurry sections. Details throughout are not as sharp as they normally are. That's why I reduced the mosaic from full size to one third size. It does no good to magnify imperfections.

This unusual filament is one of the most dramatic features I've ever seen on the Sun.

February Sun

Correcting Problems

The last time I used my solar telescope more than a month ago I encountered a communication problem between the telescope mount and the software controlling the mount. Up until that point the mount and software had performed flawlessly. I waited through cold cloudy January for an opportunity to investigate the problem. Finally, on February 4th, afternoon temperature reached the low 50's. Thin clouds were present, it was windy, and the seeing was not very good, but it was warm enough to work on the mount/software problem without numb fingers.

Upon startup the mount initially moves to a predetermined "home" position. If the mount is nearly aligned to the north celestial pole, the telescope will then point at the celestial equator about 30 degrees west of the meridian. If the software is properly synchronized with the mount, the software should show the telescope pointing at the celestial equator 30 degrees west of the meridian. When I began my problem solving session on February 4th the telescope itself seemed to be pointing at the correct position in the sky above. The software, however, showed the telescope pointing well below the celestial equator. In other words, the telescope mount and the software were "not on the same page". I hoped I could correct the problem by simply moving the telescope to the Sun and "synchronizing" on the Sun. After this synchronization I commanded the mount to move to the "home" position. This time both the mount and the software were, indeed, "on the same page". I hope this has solved the problem. I'll know the next time I set my equipment up.

After fixing the synchronization problem I captured a few videos through the thin, thickening clouds. A few modest sunspots were scattered about along with a nice collection of filaments on the Sun's eastern side. The following 13-image mosaic made with a 2X Barlow lens shows most of the interesting features. (Click on the images below for a larger view.)

Filaments show up nicely in the following inverted view.

Sunspot 2280 is just to the right of the largest long filament. This filament seems to have a drooping tail hanging from its left end.

Sunspot 2277 was located near center of the solar disc. It is spread out between a prominent dark umbra on the upper left and a group of smaller spots on the lower right.

Details are not bad considering the relatively poor seeing conditions and thin clouds. I've never before started observing as early as February 4th.