Draw Mercury: Crater Placement and Tonal Shading Steps

Object Drawing Lessons

This lesson teaches a repeatable method for drawing Mercury as a single sphere with craters and tonal shading. You will define a light direction, place craters in a believable pattern, draw a terminator line that separates lit and shadowed hemispheres, and shade in layers. The convention is simple: the planet outline is a circle; the terminator is a smooth curve from one edge of the circle to the other; craters are drawn as ellipses whose long axis follows the local surface direction. Letter styles and handwriting vary, so the rubric rewards clear, consistent choices rather than one universal look. All measurements below are hypothetical examples; measure your own paper and tools before drawing.

Practice materials: Printable downloads are not available for this lesson yet. Use the instructions and four exercises below.

Set the sphere and light direction

Begin with a circle for Mercury. A clean circle is the foundation for believable shading. Use a light pencil outline so you can adjust it. Mark a small arrow outside the circle to show the light direction. For this lesson, assume light comes from the upper left at about 45 degrees. This is a hypothetical choice, not a standard.

Draw a faint vertical and horizontal axis through the circle center to help place features. Keep these guide lines light; they will be erased or left faint. The light arrow tells you which side of the sphere will be lit and which will fall into shadow.

1. Draw a circle about 8 cm across on plain paper; measure your own circle and record the diameter.
2. Mark the center with a small dot and draw faint vertical and horizontal axes through it.
3. Draw an arrow outside the circle pointing from upper left toward the center to show the light direction.
4. Label the upper-left edge as the lit side and the lower-right edge as the shadow side.

Place craters with a simple pattern

Craters on Mercury are not evenly spaced, but for a clear drawing you can use a controlled pattern. Place three to five craters: one near the lit side, one near the center, and one or two toward the shadow side. Avoid placing a crater exactly on the terminator line, because the shading will make it hard to read.

Draw each crater as an ellipse. The long axis of the ellipse should follow the curve of the sphere at that point. Near the center, the ellipse is nearly circular; near the edge, it becomes narrower. Add a small inner curve on the side facing the light to suggest the crater rim. Keep crater sizes varied but plausible: a large crater about one-fifth of the circle diameter, medium craters about one-tenth, and small craters smaller still.

1. Choose three crater centers: one at upper left inside the lit area, one near the center, and one at lower right inside the shadow area.
2. Draw a large ellipse at the center crater, with its long axis following the local surface curve.
3. Draw a medium ellipse at the upper-left crater and a small ellipse at the lower-right crater.
4. Add a short inner arc on the light-facing side of each crater to suggest the rim.
5. Check that no crater sits exactly on the planned terminator curve.

Draw the terminator and shade in layers

The terminator is the boundary between the lit and shadowed parts of the sphere. For light from the upper left, draw a smooth curve from the top edge of the circle to the bottom edge, bowing slightly toward the lower right. This curve should pass through the shadow side, leaving most of the upper-left area lit. Keep the curve smooth and continuous.

Shade in three layers. First, apply a light tone over the entire shadow side, stopping at the terminator. Second, darken the area nearest the lower-right edge to suggest the sphere curving away from the light. Third, add a narrow darker band just inside the terminator on the shadow side to show the transition. Leave the lit side mostly clear, with only faint shading near the lower-left edge to suggest curvature. Use consistent pencil pressure and blend gently with a tissue or soft brush if available.

1. Draw a smooth terminator curve from the top edge to the bottom edge, bowing toward the lower right.
2. Shade the shadow side with light pencil strokes, keeping the terminator edge clean.
3. Darken the lower-right edge with a second layer of shading.
4. Add a narrow darker band just inside the terminator on the shadow side.
5. Add faint shading near the lower-left edge of the lit side to suggest the sphere's curvature.
6. Erase guide lines if desired, and check that the light arrow, craters, terminator, and shading all agree.

Check your drawing against the convention

A valid Mercury drawing follows the stated convention: one circle, one light direction, craters placed away from the terminator, a smooth terminator curve, and layered shading that darkens toward the shadow edge. Handwriting and letter styles do not affect the drawing score, but labels should be readable. Because art allows valid alternatives, the rubric checks consistency and clarity rather than exact crater positions.

Measure your circle diameter and crater sizes with a ruler. Record the values. If your terminator curve crosses a crater, adjust the crater position or the curve. If the shadow side is uniformly dark, add a lighter band near the terminator to show transition. These checks make the drawing self-consistent.

1. Measure the circle diameter and the long axis of each crater; record the values in centimeters.
2. Confirm that the light arrow points from upper left and that the terminator bows toward the lower right.
3. Check that no crater center lies within 5 mm of the terminator curve.
4. Confirm that the shadow side has at least two distinct tone layers and the lit side remains mostly clear.

Worked example

A student draws a circle 10 cm across with light from the upper left. They place a large crater at the center, a medium crater at upper left, and a small crater at lower right. Their terminator curve bows toward the lower right. They shade the shadow side with one uniform dark tone. Identify one improvement and explain how to check it.

Four practice exercises

Common mistakes

• Placing craters evenly around the circle like a clock face. Use a varied but controlled pattern: one crater in the lit area, one near the center, and one or two in the shadow area, with different sizes.
• Drawing the terminator as a straight vertical line. Draw a smooth curve from the top edge to the bottom edge, bowing toward the shadow side to show the sphere's curvature.
• Shading the entire shadow side with one uniform dark tone. Build tone in layers: light tone near the terminator, darker tone toward the shadow edge, and a narrow transition band just inside the terminator.
• Drawing craters as perfect circles everywhere on the sphere. Use ellipses whose long axis follows the local surface curve; near the edge, the ellipse becomes narrower.

Self-check rubric

• Circle is closed and roughly round; diameter is measured and recorded in centimeters.
• Light direction is shown with one clear arrow and is consistent with the terminator and shading.
• Three to five craters are placed with varied sizes and away from the terminator curve.
• Craters are drawn as ellipses whose long axis follows the local surface curve.
• Terminator is a smooth curve from one edge to the other, bowing toward the shadow side.
• Shadow side has at least two distinct tone layers, with a darker edge and a transition band near the terminator.
• Lit side remains mostly clear, with only faint shading to suggest curvature.
• Labels and notes are readable; handwriting style does not affect the score.

Questions and answers