Sun, shadows and the day-and-night map

Two tabs deal with the Sun: Sun & shadow for a single spot, and Day and night map for the whole planet. Open File → Templates… → Garden shadow planner to follow along with a 6 m tree in Munich at the March equinox.

Sun and shadow now

Enter Object height and choose metres or feet in Unit. Skyfold then shows for the moment in the side panel:

• the shadow length and compass direction in large type, for example Shadow: 14.34 m towards the north-east (62°),
• Sun altitude and Sun azimuth (degrees from north, clockwise),
• Shadow length ÷ height — handy for any other object: multiply its height by this number,
• Sunrise · solar noon · sunset and Evening golden hour begins.

The plan view draws the scene from above with north up. The bold line is the shadow now; the dashed line traces the tip of the shadow through the whole day. Drag Time of day in the side panel and watch the shadow turn. On the equinoxes the dashed line is straight; in summer it curves away from the Sun's side, in winter towards it.

When the Sun is less than half a degree above the horizon a shadow becomes endlessly long, and at night there is none — Skyfold says so instead of showing a number.

Shadow through the day

The table Shadow through the day lists every full hour with the Sun's altitude and azimuth, the shadow length and its direction. Use it to check whether a terrace stays in the sun in the afternoon, or how far a new extension would shade the neighbour's garden in December (change Local date to the 21st).

The calculation assumes flat, level ground and a thin vertical object. Slopes, walls and the width of a building change real shadows; treat the numbers as a careful first estimate.

The day-and-night map

Day and night map shows the whole Earth at the moment in the side panel. The darker the shading, the deeper the night: the light band is the sunset line, then civil, nautical and astronomical twilight and finally full night. The yellow dot marks where the Sun stands straight overhead; your place is marked in orange.

Switch on Follow the current time (updates every minute) to turn the map into a live clock of the planet. Under the map you read the coordinates of the point under the Sun and the Sun's altitude at your place.

Export → Day and night map as SVG saves a large vector version for slides or prints.

Next: print a star map poster.