Lunar libration is a 'wobble' caused mainly by the Moon’s elliptical orbit and axial tilt. It allows us to see about 59% of the Moon's surface over time, effectively revealing 18% of the 'far side' that would otherwise be hidden. This post discusses this interesting phenomenon. Updated 7 January 2026 Many people think that the… Continue reading How we can see some of the Moon’s far side
A friend of mine recently asked me whether it was possible to have a lunar-stationary orbit. This would be the equivalent of a geostationary orbit, but around the Moon rather than the Earth. To an observer on the Moon, a lunar-stationary satellite would appear fixed in the sky and if a dish were pointed… Continue reading Lunar Stationary Orbits: Why They are Impossible
This post discusses the use of latitude and longitude for mapping locations on the Moon and other celestial bodies in the Solar System. It explains how these coordinates are defined, the arbitrary selection of prime meridians, and variations across different planets, emphasizing the importance of consistent astronomical conventions for navigation and mapping.
The night of 12/13 August will be the peak of the Perseids, one of the most famous prolific meteor showers. Meteors (also known as shooting stars) are bright streaks of light caused by small lumps of rock or metal called meteoroids hitting the Earth’s atmosphere at very high speed (in the case of the Perseids around 200,000 km/h).… Continue reading The Perseids Meteor Shower 2025
For those of us in the Northern Hemisphere we're in that time of year when there is the most daylight. In this post I’ll talk about the long long summer evenings: not only does the Sun set later at this time of year but the amount of twilight, after Sun has set but it is… Continue reading Twilight and the Long Summer Evenings
Explaining Science 