Features
Hubble's greatest hits
The world’s favorite orbiting observatory has transformed our knowledge about exoplanet atmospheres, the fate of the universe, and almost everything in between.
Richard Talcott
How the Ritchey-Chrétien telescope was born
George Ritchey had great vision and skill. Henri Chrétien was a brilliant astronomer and optical engineer. Together, they created one of today’s best telescope designs.
Ron Voller
Sky This Month
Venus sidles up to Uranus
Martin Ratcliffe and Alister Ling
Star Dome and Paths of the Planets
Richard Talcott;
Illustration by Roen Kelly
Do all galaxies have dark matter?
The discovery of two ghostly galaxies created quite a hullabaloo in the astronomical community. But the jury’s still out on what’s really going on.
Jake Parks
Secrets of the Northern Pinwheel Galaxy
Think you know the big spiral M101? Take a deep dive into its myriad details, and you’ll know it like never before.
Rod Pommier
Explore the Moon at First Quarter
If you’re just starting out, our natural satellite makes a tempting target in the evening sky.
Michael E. Bakich
Ask Astro
Weighing black holes