Solar prominences are constantly changing; sometimes dramatically, other times slow enough that you don’t really notice the changes unless you’ve taken the time to a sequence of sketches over a period of a few hours.  It’s taken a lot of trial and error as well input from other astronomical sketchers to help me along through the years come up with the technique I use today for sketching prominences. Having said that, I imagine my technique and media will most likely continue changing as the years go by since I never seem to be truly happy with my sketches and how they represent such a powerful, magnificent target.  Hopefully this tutorial will give others a good starting point for developing their own style and technique.

Prominence Sketching

Tips:

• Remember that solar observing is affected by the same conditions that night-time observing is: the Sun beating down on pavement or wood decks creating quivering views, winds, eyepieces fogging up from your breath in the colder months/sweat from your eyebrows in the hotter months, even dark adaption (yes…having your eyes adjust to the darker views of hydrogen alpha so that you can see the faintest of details in prominence structure). Pick your location wisely to give you the best views for that day’s weather conditions.

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• Your eyes can detect movement sometimes easier than they can the fainter details. Some filters don’t have a flat bandwidth nor a flat field of view. Different solar features have slightly different optimal bandwidths. So…have a play with those knobs to get the most out of your session. Scan back and forth slowly, move the FOV around, notice the features popping in and out of bandwidth.

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• The types of paper and pencils you use can hinder or help you. Things to consider: sunlight glare on your paper will temporarily give you blind spots when you try to observe again after adding a marking (worse with white paper – think dark adaption when you put your eyes back to the eyepieces), texture, smudges or holds the pencil markings, colors…

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• Outside light around the eyepiece cups will prevent you from seeing the fainter details. Eyecups, towels, proper solar cloths, or even a cardboard solar shield, will help.

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Tutorial:

• I normally use black Strathmore Artagain paper, but had run out at the time I did this observation sketch. Canson paper is comparable. A clipboard is handy to keep the paper stiff and in place. Using the flat edge of white Conte’ crayon to draw the arc freehand, I make sure not to create an over-curved arc.

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• Using my fingertip, I blend the surface of the disk fairly smoothly. I’ve tried different chamois and blending stumps, but they all remove too much of the pastel, so even though my fingertip leaves oil residue, my fingertip so far has given me the best control over my blending.

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• Sometimes I add fainter markings for the anchor points, other times, the brighter markings. In this case, I used a watercolor pencil to lightly add the anchors of the prominence since this prominence was very extensive.

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• Working quickly, as most of my prominence sketches are done in 5-10 minutes, and very rarely in 15-20 minutes, I use the Conte’ pencil for adding in the brighter markings. I use an exacto knife for creating a sharp edge on my pencil. I try not to pay attention to the fainter strands of the prominence through the telescope. The bright areas make a great foundation for the rest of the sketch.

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• Switching to the watercolor pencil, I add the fainter markings. By adding the markings over portions of the Conte’ markings, you can achieve some blending at the same time.  A zoom eyepiece really helps so that you can zoom in or out depending on seeing and transparency conditions. Also, a dark cloth over your head is a huge asset for pulling out those faint details that are barely detectable otherwise.

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• A white vinyl eraser erases cleanly if needed. I sharpen mine into a wedge shaped for better control. Be careful blowing/wiping the erasure debris so that you don’t smear the sketch. Prominences are in constant motion. If you spend too long of a time sketching one, you’ll find yourself reaching for that eraser constantly chasing the changes. That’s why it’s important to build up your speed to 5-10 minutes per prominence.

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• Adding surface detail is made easy with charcoal, the brilliantly white Conte’ pencil, and a black oil/wax pencil. The charcoal creates a softer, fainter filament and is great for shading contrast in active regions or around plage. Black oil pencils leave a very crisp, sharp dark gray/black marking for the more pronounced sections of filaments/fibrils, and sunspots. White Conte’ is perfect for plage or for creating more texture for mottling.

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• Sometimes, a person just can’t resist the urge to continue along the limb or into the disk to grab more features. I do it often, myself. Don’t be hesitant about grabbing all the kit you’ve just used and add to your sketch. Sometimes, that’s when I can nab sketches of a flare or a prominence erupting right before my eyes.  What starts off as a small spicule could lead to an eruption that you’ll be glad you caught on paper.

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• To finish it off, I scan my sketch or take a photograph of it, adjust the brightness/contrast to match the true appearance of my sketch, and then I insert a graphic from the Tilting Sun program that shows the orientation for my scope and mount (dependent on how my diagonal is turned and where I am sat behind the eyepiece) and any useful information concerning my observation.

~ by Erika Rix on July 24, 2010.

Posted in Sketching Notes/Tutorials, Solar Sketching
Tags: artagain, charcoal, conte', filaments, H-alpha, prominences, sketching tutorial, solar sketches, Strathmore Artagain