Equinox: The Sun from Solstice to Solstice
23.09.2019

Today is an equinox, a date when day and night are equal. Tomorrow, and every day until the next equinox, the night will be longer than the day in Earth's northern hemisphere, and the day will be longer than the night in Earth's southern hemisphere.

Star Trails Over Vienna
14.07.2005

As the Earth spins on its axis, the sky seems to rotate around us. This motion, called diurnal motion, produces the beautiful concentric trails traced by stars during time exposures. In the middle...

Aurora Oklahoma
13.11.2003

Nestled in the central US, the state of Oklahoma is noted for its gorgeous prairie skies and wide-open spaces, but not for frequent visitations of the northern lights. Still, following the intense solar activity...

Lunation Matrix
1.10.2022

Observe the Moon every night and you'll see its visible sunlit portion gradually change. In phases progressing from New Moon to Full Moon to New Moon again, a lunar cycle or lunation is completed in about 29.5 days.

Apollo s Analemma
22.09.2013

Today, the Sun crosses the celestial equator heading south at 20:44 Universal Time. An equinox (equal night), this astronomical event marks the first day of autumn in the northern hemisphere and spring in the south.

Great Refractor and Lunar Eclipse
26.11.2021

Rain clouds passed and the dome of the Lick Observatory's 36 inch Great Refractor opened on November 19. The historic telescope was pointed toward a partially eclipsed Moon. Illuminated by dim red lighting...

Veins of Heaven
31.07.2014

Transfusing sunlight through a a still dark sky, this exceptional display of noctilucent clouds was captured earlier this month above the island of Gotland, Sweden. From the edge of space, about 80 kilometers above...

Eclipse Over The Mountain
2.09.1999

Undaunted by world wide anticipation of the August 11 total solar eclipse, the moon also performed a lunar eclipse just two weeks earlier, on July 28. Crossing the edge of Earth's shadow the moon was only partially eclipsed - but the spectacle could be seen by observers located across the Earth's night side.

Night of the Perseids
10.08.2017

This weekend, meteors will rain down near the peak of the annual Perseid Meteor Shower. Normally bright and colorful, the Perseid shower meteors are produced by dust swept up by planet Earth from the orbit of Comet Swift-Tuttle. They streak from a radiant in Perseus, above the horizon in clear predawn skies.

APOD: 2023 December 27 Б Rainbow Aurora over Icelandic Waterfall
27.12.2023

Yes, but can your aurora do this? First, yes, auroras can look like rainbows even though they are completely different phenomena. Auroras are caused by Sun-created particles being channeled into Earth's atmosphere by Earth's magnetic field, and create colors by exciting atoms at different heights.