Traverse City Record-Eagle


Sun Prominences, Plasma Trails, and Flares

Ed HahnenbergTuesday, December 4th, was a fairly active day on the sun. I had just received an Imaging Source DMK 41AU02 monochrome CCD camera to do detailed imaging of the planets, the moon, and the sun. The day was a sunny day early in the afternoon. This was going to be an experiment in imaging through my Coronado PST. I had had problems taking astrophotographs with my Imaging Source DMK 21 color camera due to its IR filter.

I have been doing a lot of research in how best to take astrophotographs of the sun.  I had taken pictures of the sun through an ordinary solar filter.  One such example is below.

However, the sun is a seething star with all kinds of activity taking place on it that you can’t see or photograph with an ordinary solar filter.  One needs to use a camera that can capture prominences, plasma trails, and solar flares.  The most popular telescope to do this with is the Coronado PST H-alpha scope or with much costlier filters for larger telescopes.

Below is an image of the Coronado mounted on my C1400.

At first my new camera was unable to reach focus. From my research I had learned that those who were successful in taking solar images used a Barlow or Powermate lens to increase the image by 2X or so. I took several images of the sun with the DMK 41, using a 2X Barlow. Focusing was done by the focus knob on the Coronado.

Here is my first image showing the edge of the sun with prominences and sun spots.

You will notice the prominences at the edge of the sun in the upper left corner which are  large, bright, gaseous feature extending outward from the sun’s surface.  A prominence forms over timescales of about a day, and prominences may persist anywhere from one hour to nearly a year, although in the hour I was imaging, these prominences decreased in size.  Most last for several weeks or months. Part of my image of the sun is washed out and the focus needs adjustment, but considering that this was my first attempt….

I took another image showing much more solar activity using the Coronado, which doesn’t just darken the Sun but picks out a very specific color of light (in the red part of the spectrum) and isolates that, letting it through while blocking everything else. Warm hydrogen (like in the filament) emits that color, so if you use that filter the loop of plasma looks pretty much the same against the Sun as it does against the sky. It’s a bit of a trick, but is useful in showing that plasma trails and prominences are just two different views of the same structure. You can see the plasma trail which looks like a dark upside-down “U”.

I will be learning how better to colorize future images of the sun despite using a monochrome camera. There are many ways to do this. I used Windows Live Photo Gallery in combination with Photoshop.

All in all I was quite pleased with my first results in this new area of astrophotography.  Click on both images for more detail.

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