Drawing Comets

Comets have the potential to take up just about the whole sky. OK, maybe not the whole sky but a pretty big chunk of it, anyway. Comets Hyakutake and Hale-Bopp most definitely fit that bill. So, too, does the transient pictured in this series of sketches, comet Ikeya-Zhang. Ikeya-Zhang graced the northern sky in March 2002. At his best, this comet stretched across seven degrees of sky. It's just not possible to do justice to such a magnificent bird by sketching on a canvas confined to a 3-inch diameter circle. For large, bright comets, a full sheet of paper is a must.

Eight stars anchor the sketch. One of the four at the bottom of the field is 3.6 magnitude Eta Piscium. At the opposite end, 2.7 magnitude Beta Arietis and 3.8 magnitude Gamma Arietis serve as reference points defining the limit of the comet.

Most of my drawings are based on telescopic views. But for an object this large, only binoculars or the naked eye will suffice. I used a pair of 10x50 binocs to make this sketch. Ikeya-Zhang was observed against a darkening night sky, during and just after twilight.

With the sketch anchored, I draw the comet head, outline the main dust tail and fill in the sky around the comet with more stars. The comet head rests about one degree from Eta Piscium. The brightest portion of the tail stretches east-northeast over a distance of about five degrees.

I didn't draw every visible star, just enough to provide a suitable framework for the comet. Since the sky was growing darker, more stars were appearing over the course of the drawing. Of the roughly 40 stars shown at this stage of the sketch, the faintest shine at about 7.0 magnitude.

As twilight yielded to full darkness, the comet's frosty tail lengthened considerably. By the time the sketch was complete, it reached a full seven degrees across the sky. More stars were visible, too. Nearly 60 adorn the drawing, the faintest dimly glowing at 8.6 magnitude. Stroking along the length of the tail with my fingertip produces a soft, gauzy look. Then, a few strokes of the pencil darken the brightest portions of the tail. The comet nucleus appears bright and slightly elongated in alignment with the dust and gas tails. Gas tails often have a feathery appearance. Short, quick slashes of the pencil followed by more finger rubs produce the desired effect.

The drawing is finished as any other would be. I compare the drawing to a MegaStar chart. The stars are scaled in size to indicate relative brightness. Notice how Eta Piscium, and Beta and Gamma Arietis are now quite pronounced in the image. A few last strokes of the pencil and some final smudges with a fingertip complete the sketch. The end result is a drawing that captures the delicate majesty of a bright comet.

These ghostly creatures appear only every few years, if we're lucky, and rarely with much advance notice. Then after a brief stay, they're gone forever, just as quickly and mysteriously as they appeared. A sketch allows us to relive the moment, again and again, and to share the experience with future generations. A sketch carries more magic than mere words and is more personal than a photo. For it tells the story not just of the object's visit, but of our experience of that visit. And that's a story worth telling.