Friday, October 17, 2014

Imperfect Conditions

Limited Features

A great solar observing session requires cloudless skies, good seeing, and dramatic features spread over the whole Sun. Although the sky was clear on October 5th, seeing was poor much of the time. Modest features covered only about half the Sun. Imperfect observing conditions, yes, but what a lovely day! It was nice to observe without sweating, freezing, or fighting insects.

Some nice prominences graced the Sun's western limb as shown in the following 5-image mosaic made with a 2X Barlow lens. (Click on the images for a larger view.)
It's hard to capture prominences without overexposing features on the much brighter disc. The next image shows why I covered disc features with a black occulting circle above.
During a period of decent seeing I recorded videos for the following 8-image mosaic showing detailed disc features in the Sun's western half. Sunspot 2182 is below center. Sunspot 2178 is on the right above center. Sunspot 2181 is very near the right edge. Three or four vertically oriented dark filaments add to the scene.
I include the next example to show what can go wrong when constructing a solar disc picture from separate individual images.
This picture above is an 18-image mosaic. You can see how some sections are blurry and some are relatively sharp. The blurry sections were recorded when the seeing was bad causing solar features to swim around in unsteady air. One sharp section near the top is surrounded by blurry sections. It also has a different brightness than its neighbors because I screwed up the recording settings for that one image. The flaws become more noticeable if you click on the image for a larger view. Even though this mosaic failed, it does show a u-shaped filament in the lower left and an erupting sunspot near the limb in the upper right. Look for these features in the larger view. Finally, here's a closer view of the u-shaped filament.

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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