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.