Planetary Drawing
A great many amateurs of long standing sketch and draw what they see at the eyepiece, indeed it is something that I do if the seeing is good enough to show a steady image every time I observe a planet, and will definitely allow you to record something if the seeing is not good enough for imaging with either film or electronic means. The greater benefit is that by observing fine detail while making your sketch, you will notice details that you would not otherwise notice from casual observation or from perusing a recorded image. Images can be made in good seeing that combined with your sketch, will yield a much more detailed record of your observation.
Drawing Planetary surfaces isn't as hard as you would think, as long as you remember to follow a few simple steps to make the process easier. To begin, use a pre-formatted blank such as the ALPO Mars form that can be downloaded at Mars Section Forms
Next you need a few materials such as some 2B, 4B, and 6B soft drawing pencils and an artist's gum eraser and of course your astronomers red flashlight, as well as a clipboard to hold your form while you are drawing. If you print your forms on heavier paper, it is as good as an artist's pad.
Telescopic image of Mars.
This will be the image of Mars from which we make our drawing at the telescope:
STEP 1:
The circle on the form is 42mm in diameter for scaling purposes and this is where we start.
STEP 2:
Draw in the phase dark limb and the polar cap, detail can be added later.
STEP 3:
Rough in the dark areas.
STEP 4:
Smooth out the dark areas.
STEP 5:
Draw in the darker details and use the eraser to lighten the light areas.
STEP 6:
Draw in and smooth the finer details.
STEP 7:
Finish smoothing and lightning, touch up fine details and you are done. Drawings can be done through different colored filters to show the distinct differences at various wavelengths and later combined into a composite drawing. Remember that the planet is rotating so you should finish your sketch within 20 minutes of starting. Be sure to record your start and finish times so as to be able to calculate the Central Meridian and identify the features in your drawing. Punch with a 3-hole punch and place in a binder and you have a log of your observations for comparison over the years that will show not only your increasing observing skills but actual changes in planetary surfaces and atmospheres.
Composite drawing.
For further information see Eye on the Sky – Jupiter and the Race Against Time, By Stephen James O'Meara | Sky & Telescope May 2004, p. 85-86
Also check out this link for digitizing techniques Belt of Venus
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