Comet over California
7.03.2008

Still gracing northern skies, a fading Comet Holmes lies at the top edge of this colorful skyview, recorded on March 4. The reddish emission nebula below it is NGC 1499, also known as the California Nebula for its resemblance to the outline of the state on the US west coast.

From California to the Pleiades
22.11.2013

An astronomical trip from the California Nebula to the Pleiades star cluster would cover just 12 degrees across planet Earth's night sky. That's equivalent to the angular extent of 25 Full Moons, as your telescope sweeps over the borders of the constellations Perseus and Taurus.

APOD: 2025 October 15 Б Rocket Launch Plume over Tucson
15.10.2025

Yes, but can your sunset do this? Looking west from Tucson, Arizona, USA one day last month, the sunset sky looked strange when it briefly lit up with the plume of a rocket launched from California a few minutes earlier.

Strawberry Sun
29.08.2013

This striking, otherworldy scene really is a view from planet Earth. The ochre sky and strawberry red sun were photographed on August 22nd near the small village of Strawberry, California, USA. Found along Highway...

A Space Shuttle Over Los Angeles
26.09.2012

It's not every day that a space shuttle lands at LAX. Although this was a first for the major Los Angeles airport hub, it was a last for the space shuttle Endeavour, as it completed its tour of California skies and landed, albeit atop a 747, for the last time.

Sutter s Mill Meteorite
28.04.2012

Last Sunday's bright fireball meteor falling through skies over California and Nevada produced sonic booms over a broad area around 7:21 am. Estimates indicate the meteor was about the size of a minivan.

Point Reyes Milky Way
12.03.2022

Northern winter constellations and a long arc of the Milky Way are setting in this night skyscape looking toward the Pacific Ocean from Point Reyes on planet Earth's California coast. Sirius, alpha star of Canis Major, is prominent below the starry arc toward the left.

APOD: 2025 November 12 Б A Super Lunar Corona
12.11.2025

What are those colorful rings around the Moon? A corona. Rings like this will sometimes appear when the Moon is seen through thin clouds. The effect is created by the diffraction of light around individual, similarly-sized water droplets in an intervening but mostly transparent cloud.

An Unexpected Rocket Plume over San Francisco
11.11.2015

What is that unusual light in the sky? A common question, this particular light was not only bright but moving and expanding. It appeared just as the astrophotographer and his friend were photographing the Golden Gate Bridge in San Francisco, California against a more predictable night sky.

A Force from Empty Space: The Casimir Effect
17.09.2002

This tiny ball provides evidence that the universe will expand forever. Measuring slightly over one tenth of a millimeter, the ball moves toward a smooth plate in response to energy fluctuations in the vacuum of empty space.