Monday, August 29, 2011

Movie Sequel

Sequel Mentioned in Previous Post

A movie sequel is often not as good as the original. My second movie produced from images taken on August 20 is not as interesting as the previously posted movie. The previously posted movie showed sunspot 1271. Another significant sunspot visible on August 20 was sunspot 1272 shown here on the left as it approached the Sun's rim:
(Click for full detail.)
 Sunspot 1272 did not show much activity at the time I observed. Thirty minutes in the life of this sunspot between 10:25am and 10:55am EDT is shown below:
(This might take some time to load before it plays at proper speed.)
Seeing conditions were rapidly deteriorating while this video was recorded, so some of the frames are a bit blurry. Some rotation is also visible because I still haven't completely mastered image alignment. On the other hand, there are a couple of small gas eruptions near the bright area in the center and this movie took much less time to produce than my first movie. I'll be trying more movies in the future.

Friday, August 26, 2011

Movie Premiere

Solar Action on August 20, 2011

Two nice sunspot groups were visible on the morning of August 20th. Using a 2X Barlow lens on my Lunt 100mm h-alpha solar telescope I made the following panorama of the two groups. Notice how the magnetic fields of the sunspots disturb and change the shapes of swirling gases in their vicinity.
Sunspot 1271 on the left and sunspot 1272 on the right. (Click for full detail.)
Here's how sunspot 1271 appeared to a human eye at the telescope's eyepiece:
Sunspot 1271 (Click for full detail.)
Gases on the solar surface are constantly moving. During this observing session I attempted to make a movie of the moving gases which appear frozen in still images. I made 31 videos of sunspot 1271. Each video was about 30 seconds long containing 400 frames. I recorded one video every 60 seconds for 31 minutes before losing my nerve. Each video produced a single detailed still image made by stacking together the 200 clearest frames in the video. Tedious labor produced 31 still images, one for each minute. These 31 still images are then played in succession to produce the following movie:
31 minutes in the life of sunspot 1271 (This might take a while to load.)

The movie follows sunspot 1271 from 9:48 am to 10:19 am EDT. Motions happening over 31 minutes are shown in 3.1 seconds (in a repeating loop). In particular, notice the erupting gas plume in the lower left corner and the spouting plumes near the center!

It took four days to make this simple movie while I stumbled slowly up the learning curve. A full hour of solar action would be better, but it would have taken at least twice the time to process the resulting 60 images! I'll have to get more efficient to produce longer movies in the future.

The imperfections are fairly obvious. First, I had considerable difficulty getting the 31 images aligned. The telescope does not track perfectly, so all the still images were slightly shifted and rotated relative to each other. I had to manually align the images because I could not figure out how to get automated alignment software to do the job. You can see how the image seems to wiggle slightly as the movie plays because the alignment is not perfect. Also, in the upper right corner you can see what look like clouds jiggling over the movie. These are caused by annoying dust spots somewhere in the optical path. I'm convinced the offending dust is somewhere in the telescope and not in the camera or Barlow lens. My attempt to erase the offending dust shadows had only limited success.

Look for a sequel to the sunspot 1271 movie in a future post. I also have 30 recorded minutes of the other sunspot, 1272.

Friday, August 19, 2011

Inconstant Star

Pulsations of S Cassiopeiae

Here's the third example of my not widely shared observations made at Winfree Observatory at Randolph Macon Woman's College (now called Randolph College).

Some things we want to remain constant:
  • Good health!
  • Good friends!
  • The Sun!!!
Without a constant Sun we are all in big trouble! Is the Sun truly constant? Fortunately, solar energy output doesn't vary much. For example, look at this graph:
From 1975 to 2007 the Sun's power output (measured in watts per square meter arriving at Earth) only changed by about 0.1 percent. Consequently, Earth didn't freeze or fry by deadly amounts. But many stars on the path to extinction are not constant. Some of these stars drastically change brightness while pulsating in and out! One such star is called S Cassiopeiae (the variable star S in the constellation Cassiopeia). This star is located by the red X to left of the constellation Cassiopeia in the picture below:
(click to enlarge)
S Cassiopeiae slowly pulsates and changes brightness with a period of 612 days. Perhaps a drastically sped up version of its appearance would look something like this:

I measured the brightness of S Cassiopeiae at Winfree Observatory from 2001 to 2009. Here's a graphical record of my observations:
(click to enlarge)
The vertical scale is an astronomer's (logarithmic) scale of brightness measured through a photometric green filter (also known as a visual, or V, filter). The smaller the magnitude, the brighter the star. The horizontal scale shows elapsed time, measured in days, running from September, 2001 to February, 2009. There are gaps in the graph because many times observations were impossible. Sometimes the view to S Cassiopeiae was blocked by trees. Sometimes the weather was bad for weeks on end. Sometimes the telescope was down for repairs.The brightest measurement I have is magnitude 8.45 and the dimmest measurement is magnitude 16.61. This corresponds to a change in brightness by a factor of about 1840! In other words, the star S Cassiopeiae can become 1840 times brighter than its minimum brightness! If our Sun varied this much we would all be dead!

Thursday, August 11, 2011

Sunspot Exit

Sunspot Parade Ends!

On August 1 three large sunspot groups were spread in a line across the Sun. Ten days later, on Wednesday, August 10, solar rotation had carried them around almost entirely from the Sun's Earth-facing side. Only active, flare emitting spot number 1263 remained right on the Sun's edge. In the images I made below on August 10 you can see gases erupting from sunspot 1263 at the bottom of the Sun's rim.
Spiky gas columns emerge from sunspot 1263 at bottom (Click for full detail)
The red image above was taken at 9:38 am.  The next image of the same sunspot was taken 34 minutes later at 10:12 am, magnified 2X, and colored differently.
The shape of the gas eruptions seems to have changed. (Click for full detail)  
Three minutes later it looked like this:
The gas plume on the left seems to have changed. (Click for full detail)
Finally, 19 minutes later at 10:34 am the eruption looked like this:
The eruption seems to have changed again. (Click for full detail)
During this imaging session I was plagued with poor seeing (atmospheric wavering), and poor tracking. I suspect some of the gas cloud shape changes may not be true changes. Instead, they may be caused by the way the camera handles brightness variation across the solar image. I'm disappointed by the lack of crisp detail in some of these images. When the telescope is buffeted by wind, when the images are drifting in the field of view, and when the air is unsteady, it's hard to get sharp detail.

Just for fun, here's one more image of a prominence on the side of the Sun opposite from the previous images.
Nice prominence (Click for full detail)
What do you think of the blue-shaded false color? It seems to make details easier to see than the true red color or grayscale.

Thursday, August 4, 2011


Gas Clouds On The Solar Rim

Here are two final images from my August 1 observing session. It took extra time to process these since there is a huge difference in brightness between the solar disk and the glowing gas hanging above the solar rim.

I have blacked out the drastically overexposed solar disk and added red color to approximate the visual appearance of the prominences.
Some solar prominences on August 1. (Click for full detail.)
View of the rim opposite the one shown in the image above. (Click for full detail.)

Tuesday, August 2, 2011

Sunspots Galore

Solar Imaging Is Improving!

Three huge sunspot groups continued their parade across the Sun on Monday, August 1.

Monday morning I began imaging at prime focus with intention to produce a panorama of the entire solar disk. The following image is the result of processing seven, 400-frame videos. Approximately 200 individual frames from each video were saved and combined together to produce seven individual images of slightly different portions of the solar disk. Finally, these seven individual images were knitted together in Photoshop to produce the image below:
Notice the numerous prominences around the rim! (Click to see full detail.)
I'm still learning how to colorize the grayscale images produced by the camera. The telescope produces a pure red image that looks something like this:
Unfortunately, the prominences look rather dim in this colorized view.
After recording the videos for the disk panorama I used a 2X Barlow lens to get magnified images of each individual sunspot group. Here's the upper group:
The upper sunspot group. (Click for full detail)
Here's the middle sunspot group. It recently emitted a solar flare and sent a blast of particles toward Earth. Check out the spectacular arching loop of gas just left of center!
The middle sunspot group. (Click for full detail.)
Finally, here's the bottom sunspot group:
The bottom sunspot group. (Click for full detail.)
You are looking at magnetic fields gone wild!

People say I'm crazy doing what I'm doing
Well they give me all kinds of warnings to save me from ruin
When I say that I'm o.k. well they look at me kind of strange
Surely you're not happy now you no longer play the game

People say I'm lazy dreaming my life away
Well they give me all kinds of advice designed to enlighten me
When I tell them that I'm doing fine watching shadows on the wall
Don't you miss the big time boy you're no longer on the ball

I'm just sitting here watching the wheels go round and round
I really love to watch them roll
No longer riding on the merry-go-round
I just had to let it go

John Lennon