Guide three
Moon Watching
You do not need any equipment to enjoy a full moon. A little planning, though, turns a glance into a proper look.
Moonrise and moonset
A full moon is opposite the sun in the sky, so it rises in the east around sunset and sets in the west around sunrise. Each night after full moon, the moon rises later, on average by about 50 minutes. Check a local moonrise table for your city.
Why the rising moon looks huge
The moon near the horizon looks much bigger than when it is high overhead, but it is not. This is the moon illusion, a trick of perception. Photographs taken at both times show the same size disc. The warm orange colour at rising is real: moonlight passes through more air near the horizon, which scatters blue light away.
Supermoons and micromoons
The moon’s orbit is an ellipse. A full moon near the closest point looks up to about 14% larger and about 30% brighter than one near the farthest point. Popular usage calls these a supermoon and a micromoon. The difference is hard to see by eye without a side-by-side comparison.
Blue moons and eclipses
- A blue moon today usually means the second full moon in a calendar month. The older meaning is the third full moon in a season with four.
- A lunar eclipse can happen only at full moon, when the moon passes through Earth’s shadow. During a total eclipse it often turns a coppery red. Lunar eclipses are safe to watch with the naked eye.
What to look for
| With | You can see |
|---|---|
| Eyes alone | The dark maria, the “face” or “rabbit” patterns |
| Binoculars | Bright craters such as Tycho and Copernicus, with rays of pale material |
| Small telescope | Craters, mountain ranges and shadows near the edge of the disc |
The full moon is actually a poor time to see craters in relief, because the sun is shining straight down and there are few shadows. A few days before or after full moon, the line between light and dark shows the most detail.
Photographing the full moon
- Use a tripod or rest the camera on something steady.
- Expose for the moon, not the sky. A useful starting point is the Looney 11 rule: aperture f/11 and a shutter speed of 1 divided by the ISO, for example 1/100 second at ISO 100.
- For a big moon beside a landmark, stand far away from the landmark and use a long lens.
- On a phone, tap the moon and lower the exposure until the surface shows detail.
Never look at the sun through binoculars or a telescope. If you are observing near sunset as the moon rises, keep optics pointed well away from the sun.