Kiertolasku

Kiertolasku is a Finnish term that describes a specific type of lunar eclipse. Literally translated, "kiertolasku" means "orbiting decrease" or "circling decrease." It refers to a lunar eclipse that occurs when the Moon passes through the Earth's shadow. This phenomenon is observable from Earth as the Moon's brightness diminishes and, in some cases, takes on a reddish hue.

Lunar eclipses happen when the Sun, Earth, and Moon align in a straight line, with the Earth positioned directly between the Sun and the Moon. The Earth's shadow is cast upon the Moon. There are three main types of lunar eclipses: total, partial, and penumbral. A kiertolasku encompasses any of these variations. The term is not a scientific classification but rather a descriptive Finnish word for the event.

The visibility of a kiertolasku depends on the observer's location on Earth. During an eclipse, the Moon does not disappear completely but can often appear a deep red or coppery color. This is because sunlight is filtered and refracted through the Earth's atmosphere, with the red wavelengths being scattered less than others and reaching the Moon. The exact color and brightness can vary depending on the atmospheric conditions on Earth at the time of the eclipse. Observing a kiertolasku is a relatively common astronomical event and does not require any special equipment, though binoculars or a telescope can enhance the view.