Sunspots Bloom

Holiday Display

On November 23rd, Thanksgiving day, the Sun displayed beautiful features. It happened to be a rare cloudless day in my part of the world! This imaging opportunity was too good to pass up, so I hauled my equipment outside in cool autumn conditions. Temperature ranged from 47 to 50 degrees while I worked in gentle breezes. It was comfortable in a light jacket. Unfortunately, the Sun was relatively low in the sky, and atmospheric seeing was mediocre. Nevertheless, it was thrilling to witness solar activity this day. The next image reveals why I was so happy. (Click on images to enlarge for better detail.)

The previous image is a mosaic consisting of 37 individual panels. I superimposed a 20-panel disc mosaic on top of a 17-panel prominence mosaic. Major sunspots appear in the left (eastern) hemisphere, and dramatic prominences are scattered all around the limb. A nice filaprom hangs on the eastern limb. Although this mosaic isn't perfect, it's one of the best I've ever produced.

There seems to be something like a quantum mechanical uncertainty principle when it comes to simultaneously capturing both disc and prominence detail. If exposures and processing are chosen to best show disc detail, then prominence detail diminishes. If exposures and processing are chosen to reveal prominence detail, then disc detail is overexposed and washed out. The only ways I know to exhibit both disc and prominence detail is to either superimpose two separate images, or to process disc and prominences separately within the same image. The first image above is an example of superimposing two separate images. The next image is an example of processing disc and prominences separately within the same image. It shows, diagonally up from left to right, sunspots 3500, 3494, and 3493 along with dramatic prominences on the limb.

The image above was captured at 9:37 EST. At 10:21 EST, 44 minutes later, the middle prominence had evolved into a faint, wispy structure shown in the next 3-panel mosaic processed to exhibit prominence detail. Notice how disc detail is overexposed and washed out in order to reveal the dim prominence. Also notice the nice "filaprom" (prominence to filament transition) farthest up on the limb to the left of the upper sunspot group.

The second large sunspot group, filaments, and a prominence are shown in the next image.

Sunspots above are, from left to right, 3491, 3492, and double umbra 3490. They make an attractive scene.

Two smaller sunspot groups along with the 3491, 3492, 3490 group are visible in the next image. It was constructed by cropping a 7-panel interior disc mosaic.

Sunspot group 3489, with three small umbras, is below center, while another small spot, 3498, is near the right edge. A larger view of sunspot 3489 is shown next.

Finally, I caught two small flares in progress before ending this observing session. The next two images show the first flare, a white overexposed area below double-umbra sunspot 3490. The top image was captured at 9:15 EST. The bottom image shows the flare erupting 83 minutes later at 10:38 EST.

The second flare appears as two white overexposed areas on either side of a dark filament sitting to the left of sunspots 3493/3494. The top image below was captured at 10:04 EST. The bottom image shows the flare eruption 20 minutes later at 10:24 EST.

Seeing conditions significantly deteriorated as noon approached signaling an end to this very productive observing session.

 



 

Sunspots Return

Lots of Filaments

Sunspot numbers and solar features had decreased significantly during October. Many nice clear mornings were available for imaging, but I let them pass without hauling out my equipment. Finally, on November 3rd, enough interesting features appeared to make observing worthwhile. It was 50 degrees under a cloudless autumn sky. Although there was no wind, seeing was mediocre. Two major sunspots were visible along with a good variety of filaments as you can see in the following 22-panel mosaic made with a 3X Barlow lens. (Click on images to enlarge.)

Sunspot 3477 has the darkest umbra on the lower left. Small, newly emerging sunspot 3480 is to the left of 3477 near the limb. Double umbra sunspot 3474 is near the right limb. A dramatic sinuous filament stretches out from the left edge.

The previous image was processed to show disc details. The next image, processed differently, shows prominences around the limb.

Three examples of "filaproms" are visible above. These reveal gradual transition from prominence to filament when a prominence extends from the limb onto the disc. The "filaproms" show up even better in the next 14-panel mosaic made from images obtained with camera settings specifically chosen to brighten prominences. Unfortunately, disc features are overexposed as a consequence.

There's one "filaprom" at the top, one at the bottom, and one on the left edge of the sinuous filament. I don't think I've ever captured so many "filaproms" at once!

Next are closer views of the eastern hemisphere showing both sunspot 3477 and the sinuous filament.

Finally, a close detailed view of filaments in the northern solar hemisphere shows them well when the image is viewed at full size.

Sunspot numbers are predicted to increase in coming months as the solar activity cycle gradually approaches maximum.
 

Halloween Fun

Neighborhood Displays

I'm enjoying some interesting Halloween decorations near my home. Sizes are often amazing. For example, look at this enormous Jack Skellington figure I frequently pass on bike rides. It's almost as tall as the two story house behind!

 

Another giant display is a huge inflatable black cat. Once again, houses nearby give a sense of scale.

The cat's spine is lit at night!

This giant scarecrow's hat reaches second story windows.

A really nice multi-spook display includes another scarecrow holding his grim reaper scythe. The werewolf is particularly cool, and the flying witch is suspended in mid air. (Click on images for a larger view.)

At night werewolf eyes glow eerily, but true color doesn't show well in the following nighttime photo.

Finally, my favorite display is the skeleton picnic erected by my son-in-law. Their card game is accompanied by a pizza box!

The picnic is colorful at night, although the photo below doesn't capture true color.

Halloween decorations these days are much more elaborate and amusing than any in my childhood memory.
 

Clear Sky Continues

Nice Prominence Display

As mentioned in the previous blog, I spent several hours on the evening of September 15th capturing 233 individual images of various celestial objects. With much of my equipment left outside, I stumbled into bed at 1:40 AM on September 16th. Clear sky persisted into the morning of the 16th. I dragged myself out of bed after too few sleeping hours and went for a run. Then I hustled outside to image the morning Sun while good conditions continued. Equipment accumulated dew overnight which I dried off with towels. Mounting my solar telescope took less time than usual because more than half the equipment was already outside.

Not many dramatic sunspots were visible, but some nice prominences were displayed around the solar limb. The next image, a mosaic of the central disc, shows the only sunspots present. Sunspot 3433 is on the left. The other sunspot pair has small umbras. Spots 3434 on the left and 3429 on the right are connected by a white, energy emitting structure. A long dramatic dark filament stretches out in the upper right. (Click on images to enlarge.)

The following 11-panel mosaic, shows the relative lack of disc features.

Although disc features may have been sparse, there were a good number of prominences around the limb. Some are shown in the next mosaic which has been processed to reveal prominences.

An arched prominence appeared on the Sun's northern limb.

The southeastern limb had some spiky emissions from an emerging sunspot.

Finally, an enormous arching prominence with one explosive spike was displayed on the southwestern limb.

By the time this solar imaging session was over I was completely exhausted. Forecasts predicted cloudy skies for the next two weeks, so I appreciated the chance to take advantage of rare clear sky.
 

 

Starry Night

Success at Last!

Sky conditions were too good to pass up on the evening of September 15th! Humid, hazy, cloudy, summer air was finally replaced by cool, clear, dry, moonless sky! In addition, by some chance miracle, all five usually annoying neighbor spotlights were turned off most of the time. Of course, perfection is hard to attain. Light poured out from one neighbor's unshaded windows. This window light was easier to tolerate than glaring spotlights, however. So, all things considered, conditions were about as good as I can hope for in my backyard. This was a great opportunity to use my Nikon Z6 2 camera with a 130 mm Stellarvue refractor.

With temperature comfortably in the mid-60's I spent time setting up equipment and bringing the telescope mount up to speed. Eventually, all was ready. Sagittarius was getting lower in the southwest, so my first photographic target was the Lagoon Nebula (M8). The next image is a stack of thirty, 20-second exposures at ISO 6400. (Click on images to enlarge.)

For some reason the nebulosity has a purple color instead of being correctly red. Ten minutes of total exposure captured a good amount of glowing gas, and the background sky is reasonably black. The small golden clump to the left is NGC 6544, a globular cluster.

Next, I moved to another object in Sagittarius, the Eagle Nebula (M16). Once again, I stacked thirty, 20-second exposures at ISO 6400 to get the following image.

Nebulosity is inaccurately purple again. More exposure time is needed for this object. If you enlarge the image and look at the nebula center, you can just begin to see the "Pillars of Creation" made famous by the iconic Hubble Telescope image of the same name.

Now it was time to leave objects near the horizon and point the telescope closer to a darker zenith. The next image of Brocchi's Cluster, also known as "the Coathanger", came out particularly well!

The Coathanger's star colors are not quite as dramatically intense as some photos I've seen, but the asterism nicely fills the frame and shows up very nicely! I'm really happy with this picture, made from a stack of fifteen, 20-second exposures at ISO 6400. The small concentration of stars in the lower left corner is NGC 6802, an open cluster.

The beautiful color contrast double star, Albireo, is in the same neighborhood as Brocchi's Cluster. I moved there next. A 2X Barlow lens was required to produce significant separation between the pair which are only 34.9 arc seconds apart. The gold star is about 60 light years closer to Earth than the blue star, so they are a chance alignment rather than an orbiting pair.

The blue and gold star colors are only apparent on the outer fringes because star centers are overexposed. I should have realized this would happen for these bright stars. In this case, fifteen, 20-second stacked exposures was overkill! If I try this again, exposures shorter than 20-seconds would be better.

Large planetary nebula M27 was also relatively nearby. With a 2X Barlow lens fifteen, 20-second stacked exposures at ISO 51200 yielded the following image.

Twenty second exposures are the limit of my unguided mount before slight star trailing begins to show up with a 2X Barlow lens.

I removed the Barlow lens and captured the Double Cluster in Perseus by stacking thirty, 20-second exposures at ISO 6400.This image shows the clusters very well at full size, so click on the image to enlarge 100 percent. A few yellow stars are scattered about.

Finally, the constellation Andromeda had risen high enough for its famous galaxy, M31, to become a target. Unfortunately, stacking only thirty, 20-second exposures at ISO 6400 did not capture enough light to fully reveal the galaxy's outer arms. The outer arms and dust lanes are only partially visible in the next image. Their visibility may depend on properties of the device screen used for viewing as well as room lighting. M31's two companion galaxies M110 and M32 are visible. M110 is the larger companion below M31 and M32 is the smaller fuzzy spot above M31. The galaxy and its companions nicely fill the image frame.

Temperature had dropped to 58 degrees near 1:00 AM. My observing stamina has diminished with age. I was getting a bit chilly. After hauling the telescope and camera inside, I left other equipment outside so I could collapse, exhausted, into bed at 1:40 AM.
 

Sagittarius Milky Way

Fighting Light Pollution

After solar imaging under absolutely clear sky on the morning of August 19th I left my telescope mount and equipment outside anticipating a cloud free night to follow. The night did continue without clouds or bright Moon, but when I stepped outside to begin setting up my Stellarvue refractor, I was immediately blinded by a neighbor's glaring backyard spotlight. I was so discouraged and disgusted I packed up the mount and began hauling equipment inside. Just as I moved the last piece inside, the neighbor turned off the light! The resulting sky was now as dark as it gets above my less than ideal neighborhood location. The Milky Way and Sagittarius were visible in the south above nearby rooftops. This night of new Moon was probably my last opportunity to photograph the Milky Way, so I hastily attached my Nikon Z62 to a tripod and tried getting some short exposure unguided photos.

After initial trial and error I started accumulating photos to eventually stack together into a single equivalent longer exposure. My work was interrupted several times by various neighbor spotlights turning on and off while dogs were let in and out. I ran out of energy after recording 145 individual exposures at various settings. Only three exposure groups gave decent results. The first picture below, a stack of twenty-one, 6-second exposures, is a wide field image obtained with the lens set at 35 mm, f/2.8, and ISO 3200. Lights and rooftops originally visible along the bottom were cropped out. (Click on images for a larger view.)

Unfortunate background noise appears in the lower left where the sky should be black. Nevertheless, bright star clouds in the Milky Way's center are visible!

The next slightly more magnified image was made from twenty-five, 5-second exposures with the lens set at 50 mm, f/2.8, and ISO 3200. The sky in lower left is darker here, but the right half of the Milky Way star clouds is missing.

Finally,  I set the lens at 70 mm, f/2.8, and ISO 6400, and took twenty-six, 5-second exposures to get the following nice view of Sagittarius. This image is the best of the three, I think.

The famous "teapot" shape of Sagittarius is outlined in the next picture along with labels for some obvious celestial objects. I was surprised to see the Lagoon Nebula and Trifid Nebula showing up!

The images above aren't awful, but they could be better. While processing images I'm always losing faint details when I make the background sky reasonably black. Total exposure times are always too short, and light pollution brightens the background sky. I did take dark frames to eliminate camera noise, but I didn't take flat field frames. Travel to a darker location might help the bright background problem, but it's extremely hard to give up the convenience of my back yard!

There's another puzzling thing I don't understand. Software I use to stack individual images into a combined single image runs on my newer laptop. When stacking is complete the software produces a final image that looks great. I tweak this final image with Photoshop (on my newer laptop) and save the image. Photoshop on the newer laptop tells me dark areas have a zero pixel brightness value, and the background looks nice and dark. When I examine this final image on my older laptop, however, the background looks bright with pixel values Photoshop (on the older laptop) now says are about 18, significantly higher than zero! Unfortunately, the unsatisfactory view on my older laptop is the same view I get on a phone, or other devices. It seems like the original zero pixel levels from the new laptop are brought up to a higher level by some mysterious process. Consequently, in order to display a dark background sky on different devices, I have to lower dark pixel values from their unexpected value of 18, down to zero. This creates an overall dimming effect on the entire image and causes dim features to disappear. 
 

Unusual Weather

Unexpected Good Conditions

Typical mid-August observing conditions in southeastern Virginia include cloudy sky, high humidity, and broiling temperatures. So it was a wonderful surprise on August 19th to use my solar telescope in low humidity and temperature ranging from 68 to 75 degrees! In addition, cloudless sky stretched from horizon to horizon. As you can see in the following satellite image, the entire state of Virginia was cloud free at 10:00 EDT! Even haze-producing Canadian wildfire smoke descending into the midwest stayed away from Virginia.

Even though solar features were not especially dramatic this day, it was hard to skip an observing opportunity with conditions so nice. The next image is a slightly imperfect mosaic constructed from 36 individual panels: 20 for the disc, and 16 for prominences. It shows a good number of prominences around the limb, several dark filaments, and five sunspots. (Click on images to enlarge.)

Sunspot 3403 is the dark umbra in upper right. Sunspot 3407 has a double umbra in the lower right. Just left of center is sunspot 3405 with smaller spot 3411 to its left. Small spot 3412 is near the left limb. None of these spots were flaring or presenting complex structure. I thought limb prominences were the best features this day. Next is a colored prominence mosaic with the disc blacked out.

Four of the major sunspots are shown in the next close view which shows good detail when enlarged.

Sunspot 3403 was accompanied by an interesting filament stretching to the right toward the limb where it begins to form a "filaprom".

Next is a closer view of three sunspots in the left solar hemisphere.

Finally, here's a close view of filaments on the lower solar disc along with double umbra spot 3407.

Clear skies continued into the evening. The Milky Way was visible to the south, so I decided to try some pictures in spite of neighbors' light pollution. Maybe some of these images will be good enough to post in my next blog.


 

Stormy Sunset

Nice Color Contrast

I stepped out on my front porch a couple weeks ago to watch an approaching thunderstorm and saw this colorful sunset. For a short time dark purple storm clouds sat upon a bright orange foundation.

Lightning bolts frequently pierced the clouds adding even more beauty to the scene. I took many photos hoping to capture lightning, but wasn't lucky enough to catch one. The picture above would have been spectacular with bright forked lightning stretching across dark clouds!
 

Lots of Spots

Sunspot Variety

Summertime in Williamsburg, VA doesn't favor astronomical observing. Almost every day is cloudy. Rare cloudless observing windows last only a few morning hours before clouds pop up. One such unusual span of clear sky happened on the morning of July 11th. For a brief two hour period there were no clouds, no wind, and good seeing. Temperature was quite warm, but tolerable, ranging from 77 degrees to 81 degrees during my imaging session.

Solar activity is humming along nicely these days. The following 15-panel mosaic shows action on July 11th. Each individual panel is a stack of 100 frames from a 1,000 frame video clip made with a ZWO 174 MM camera, attached to a 3X Barlow lens on a Lunt 100 mm solar telescope.

One major sunspot, 3363, has a large umbra below center. From top to bottom on the right are sunspots 3361, 3367, and 3366. Sunspot 3372, with spiky eruptions, is emerging around the upper left rim. A few prominences are scattered around the limb. (Click on the images to see a larger view.)

The next 2-panel mosaic shows most of the features in the western hemisphere in good detail.

Sunspot 3361 is on top. Double umbra sunspot 3367 is in the middle. Sunspot 3366 is nearing the limb on the lower right accompanied by a nice prominence. Sunspot 3362, with a dim umbra, is in the lower left. Several filaments are scattered about making a nice solar scene.

Moving to a portion of the eastern hemisphere, the following 5-panel mosaic shows big sunspot 3363 and prominences.

On the upper left rim you can see a "filaprom". This is a prominence in the process of rotating around to become a filament when viewed against the background solar disc. While observing I noticed the development of an interesting strand of light spanning the elongated umbras of sunspot 3363. The next two images show the change. At 8:50 EDT (12:50 UT) the umbra looked like this:

Forty five minutes later, at 9:35 EDT (13:35 UT), it looked like this:

I've never seen an umbra eruption feature like this before!

Emerging sunspot 3372, just coming over the eastern limb, presented spiky, churning activity seen in profile.

Activity slowly changed in 25 minutes between 9:28 and 9:53 EDT. The next image, (slightly less sharp), shows the difference.

Inevitable clouds began appearing around 10:40, and I was beginning to feel the summer heat. It was time to shut down and haul my equipment inside to wait for the next rare cloudless sky.