Astronomy for Beginners
Here’s where you’ll find observing guides, how-to articles and great astronomy hints and tips. Don’t forget to also check out our comprehensive astronomy dictionary.
Acting like a lens, the Earth’s atmosphere diffracts the starlight passing through it causing the effect known as scintillation. It can be seen when stars appear to twinkle.
The Moon’s nearside is largely covered in relatively smooth areas, which are known as ‘seas’ or maria. These are not liquid seas like the ones on Earth, but large plains of basalt formed by volcanic eruptions. They appear darker than the surrounding regions because the basalt that they’re made from is less reflective.
This is the reflection of light usually seen around the gaseous ejections from massive stars or sometimes supernova. Perhaps the most prominent of all recently observed light echoes was the one seen around the exploding star V838 Monocerotis.