Beautiful Solar Scenery

Complex Sunspots 

Sunspots come and go, but some last longer than others. During my last imaging session on April 2nd a large active sunspot group near the Sun's western edge was about to rotate out of view. Apparently, some of this group kept active while rotating around the solar far side. On April 20th, a few days after reappearing on the Sun's Earth-facing side, the long-lived sunspots presented an interesting display. The next picture shows all the features in a single frame. (Click on all images for a more detailed view.)From left to right are sunspots 2995, 2994, and 2993. Several nice prominences are located along the rim. A complex churning active area sits between three umbras on the right. There you can see white energetic patches together with darker filaments. This region had been the source of several major flares in recent days.

April 20th was a lovely day for imaging. Aside from a few contrails, the sky was completely clear, temperature stayed in the low 50's, and only gentle breezes blew. There was a chance I might be lucky enough to catch a flare eruption, so I took several images to see if anything was changing. In the next picture I centered the sunspots and processed the image to show sunspots but no prominences.Notice the c-shaped filament on the left of the central sunspot group. As time went on this filament changed shape quite a bit. There were also a few minor energetic flareups among the white regions, but no major flares while I was watching. I made video clips once every minute for a bit more than an hour hoping to catch some activity that would show up in a time lapse movie. It takes quite a while to process more than 60 videos and assemble them into a movie. I'm still working on it.

It's difficult to display prominences in full detail without accompanying background noise. The next image is an alternate sunspot portrayal which shows more prominence structure than the first image above. Notice the hazy background brightness over the middle prominence. If I process the image to eliminate this haze, faint prominence structure also disappears. The dim haze wouldn't be so bothersome if it was uniform over the whole background. I still haven't figured out what causes the nonuniformity.Sometimes, I try to manually erase background haze to make prominences look better. This is often unsatisfactory because some prominences then look unnatural. For example, look at the next animation showing a different portion of the solar rim than the images above. (I've blacked out the overexposed solar disc.) The animation switches between the unprocessed hazy background version and the manually erased background version. You can see how the largest prominence looks unnatural when I make the background dark.Some really nice solar scenery was on display this day!

 

Good Solar Action

Umbra Eruption

It has been almost five months since my last solar imaging session. Most of that time was either too cold, too cloudy, or too windy to use my telescope. Conditions on April 2nd improved enough to dust off equipment and capture solar activity. Finally, clouds stayed away for a few hours! Finally, wind wasn't blowing 15 mph! Finally, temperature rose to a relatively comfortable 50 degrees!

It was fortunate clear skies lasted for several hours because it took quite some time to overcome initial equipment glitches. Why does my laptop want to install updates when I'm in a hurry to use it? For some reason the computer would not recognize a communication port for the telescope mount. After the communication problem was solved the mount's initial slew to the Sun was drastically inaccurate. Eventually, the Sun was centered in the eyepiece and the mount tracked well enough to begin imaging.

On this day two major sunspot groups and several filaments decorated the solar disc. The imperfect 24-panel mosaic shown below shows the features. (Click on the image to see more detail.) On the right side sunspot 2976 is near a very active white region closer to the limb. This active region had been producing powerful solar flares a few days before. Sunspot 2978, just left of center, has its own white active region nearby. Several dark filaments are scattered around, including an interesting one rotating into view against the disc on the left edge. Can you see the small sunspot near the top? The next image, a 4-panel mosaic, shows an enlarged view of the major features. (Again, click on the image to see full detail.)

The next picture shows sunspot 2976 with a prominence rising from the active area. 

The three-dimensional structure of the prominence shown above isn't captured very well in the previous image. It looked really spectacular when viewed by eye through an eyepiece! The eyepiece view showed it stretching around from the limb and suspended above the white area. Another prominence appearing spectacularly in the eyepiece was located on the opposite limb. The next picture shows this prominence-to-filament transition, but not as well as the eyepiece view.Continuing with limb features, the next image shows a chain of connected prominences on the northeastern limb. Disc features are overexposed in the last two images to bring dim prominences to visibility.

Sunspot 2978 was the best performer. When I captured the first video at 11:07 am EDT it looked like this:Notice the appearance of the dark umbra above. There's a small light area on the umbra's right side. One hour and two minutes later, at 12:09 am EDT, the umbra looked like this:A question mark-shaped bright white eruption appeared in the umbra! I've never seen anything like this before! The inverted u-shape beneath the umbra had also brightened quite a bit compared to the previous image. Twenty-one minutes later at 12:30 pm EDT the bright umbral eruption was fading.An inverted version of the previous image highlights cloud-like filaments which seem to float above the disc.The next picture shows my Lunt 100mm solar telescope on its solid mount. The cardboard box contains a laptop which controls the mount and the imaging camera:

The cardboard box and cloth drape shield the laptop from bright light. Otherwise it would be impossible to read the computer screen. A live image from the camera is displayed by the camera control software called Firecapture.

The next picture shows equipment and wires attached to the telescope.

A closer view below shows important equipment in more detail. The red cylindrical device on the left is the ZWO174MM camera. It is connected to a stubby black cylinder called a tilt adjuster which I tweak to remove unwanted interference fringes from the camera image. Next in line moving left to right toward the telescope is the smaller diameter black cylinder of the 3X Barlow lens which adds magnification to recorded images. Finally, the Barlow lens is attached to the telescope where an eyepiece would go. The white rectangular box attached to the side of the telescope tube is the Hinode Solar Guider which keeps the Sun centered in the camera's field of view. The guider sends repeated commands to the telescope mount to correct tracking if the Sun begins to stray off center due to imperfections in the mount alignment. To the right of the guider is a cylinder perpendicular to the telescope tube. The black portion of this cylinder screws either towards the tube or away to tune the etalon filter within the scope to the specific red color of excited hydrogen in the Sun's chromosphere. The camera produces a black and white image of this red light. I add a slight pale blue color to the black and white images eventually produced.

It takes almost an hour to set everything up, connect all the wires, and get the computer ready. Often it's a nervous race against time as clouds begin to move into fleeting clear observing windows. Luck was with me this April 2nd, however. I recorded plenty of good images before thin clouds began appearing .