Moon, Mercury, and Twilight Radio
8.10.2016

Sharing dawn's twilight with the Moon on September 29, Mercury was about as far from the Sun as it can wander, the innermost planet close to its maximum elongation in planet Earth's skies.

Hale-Bopp's Hoods
14.04.1997

Comet Hale-Bopp is spinning. The nucleus of the comet is a dirty snowball about 25 miles in diameter that spins about once every 12 hours. As Comet Hale-Bopp spins, parts of the comet's surface shoot away in jets.

When Diamonds Aren t Forever
30.03.2006

The track of totality for the first solar eclipse of 2006 began early yesterday on the east coast of Brazil and ended half a world away at sunset in western Mongolia. In between...

APOD: 2023 August 21 Б Introducing Comet Nishimura
21.08.2023

Will Comet Nishimura become visible to the unaided eye? Given the unpredictability of comets, no one can say for sure, but it currently seems like a good bet. The comet was discovered only ten days ago by Hideo Nishimura during 30-second exposures with a standard digital camera.

Venus On The Horizon
14.10.1997

The month of October features a sky full of planets, including Venus as the brilliant evening star. Besides the sun and moon, Venus is the brightest object visible in Earth's sky. This month, Venus appears in early evening near the red planet Mars and Mars' red giant rival Antares above the southwestern horizon.

Comet Ikeya-Zhangs Busy Tail
18.03.2002

One of the brightest comets of the past five years will likely reach its peak brightness this week. Comet Ikeya-Zhang, officially known as C/2002 C1, can now be seen without aide from a dark location above the western horizon shortly after sunset.

The Belt of Venus over the Valley of the Moon
23.07.2006

Although you've surely seen it, you might not have noticed it. During a cloudless twilight, just before sunrise or after sunset, part of the atmosphere above the horizon appears slightly off-color, slightly pink.

A Green Flash from the Sun
4.06.2014

Many think it is just a myth. Others think it is true but its cause isn't known. Adventurers pride themselves on having seen it. It's a green flash from the Sun. The truth is the green flash does exist and its cause is well understood.

Firefall by Moonlight
8.06.2017

On certain dates in February, an elusive firefall can be spotted at sunset in Yosemite National Park, when the weather cooperates and the direction to the setting Sun is just right. Often photographed from...

Road to the Galactic Center
25.10.2021

Does the road to our galaxy's center go through Monument Valley? It doesn't have to, but if your road does -- take a picture. In this case, the road is US Route 163 and iconic buttes on the Navajo National Reservation populate the horizon.