You also will spot prominences. These large gaseous features extend outward from the Sun’s limb. When you spot a prominence silhouetted against the solar disk, it appears dark because the gas is cooler. Astronomers call those features “filaments.” Solar flares, which are less common, appear suddenly bright and last up to a few hours.
Two common problems that come up while sketching the Sun through either filter are exaggerated size and misplacement of features. Oversizing results from an attempt to sketch highly detailed features in a limited space. Start with a larger circle as the solar disk; give yourself room to record your observations. And you can simplify the correct placement of solar features by using an imaginary grid for plotting.
When you sketch the Sun in Hα, maintaining dark adaption is essential — and it isn’t easy in daylight. Blocking outside light around the eyepiece with a shield or dark cloth will improve your view and let you see faint detail that otherwise would be lost. Try sketching on black paper with a white pencil. This technique reduces glare, permitting your eyes to adapt more quickly when going from sketch to eyepiece.
Once you become comfortable with solar sketching, consider creating a sketch sequence of an erupting prominence or tracking an active region as it makes its way across the disk. Sketch sequences come to life through animation with software like
Photoshop or
Gimp. View an erupting prominence animation I created at
http://wp.me/pY46X-LQ. Whichever filter you choose, with a little patience, you’ll be on your way to a lifetime of solar sketching.