The first step to capturing these details in a sketch is to use satellite prediction services like
www.Heavens-Above.com to determine where and when visible passes will occur for your location. I prefer to track the ISS manually with a Dobsonian telescope that is fitted with a wide-field eyepiece. I achieve focus on a star field prior to the pass.
Rather than writing notes, I extend eyepiece time by using a digital voice recorder to describe the space station’s appearance and how it evolves during a pass. Focus on its aspect, especially the angles of the solar arrays in comparison to the modular components. Other notable changes are color, size, and brightness. I keep a sketch pad, pencil, and observing light on hand so that once the ISS is no longer visible, I can render a series of sketches fresh from memory. To add the color and luminance, use your sketches and voice recordings to create digital illustrations of the observation, as shown in the tracking sequence by Jeremy Perez at right.