Astronomy Glossary

Telescopes Equipment

A Barlow lens is a negative (diverging) lens placed between telescope and eyepiece to multiply magnification, typically by 2× or 3×.

Galaxies

Barred spiral galaxies have a prominent linear bar structure of stars extending through the nucleus, with spiral arms originating from bar ends.

Cosmology Universe

The Big Bang theory describes the Universe's evolution from an extremely hot, dense initial state ~13.8 billion years ago, expanding and cooling to th...

Stellar Objects

Binary star systems consist of two stars orbiting their common center of mass, gravitationally bound to each other.

Telescopes Equipment

Binoculars offer wide-field, two-eyed viewing ideal for casual astronomy, comet hunting, and surveying large sky regions.

Stellar Objects

A region of spacetime with extreme gravity.

Galaxies

Blazars are AGN with relativistic jets pointed directly at Earth, producing extreme luminosity, rapid variability, and strong polarization.

Stellar Objects

Blue giants are massive, hot, luminous stars on or near the main sequence with surface temperatures 10,000-50,000+ K.