Time Lapse Auroras Over Norway
29.12.2013

Sometimes, after your eyes adapt to the dark, a spectacular sky appears. Such was the case in 2011 March when one of the largest auroral displays in recent years appeared over northern locations like the border between Norway and Russia.

Phases of the Moon
10.03.2018

Look at the Moon every night and its visible sunlit portion gradually changes. 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.

Total Solar Eclipse Corona in HDF
30.04.2018

How great was the Great American Eclipse? The featured HDR image shows it to be perhaps greater than we knew. On August 21 of last year, the Moon blocked the Sun for a few minutes along a narrow path across the USA.

Mercurys Sodium Tail
8.07.2020

What is that fuzzy streak extending from Mercury? Long exposures of our Solar System's innermost planet may reveal something unexpected: a tail. Mercury's thin atmosphere contains small amounts of sodium that glow when excited by light from the Sun. Sunlight also liberates these molecules from Mercury's surface and pushes them away.

Crepuscular Moon Rays over Denmark
27.07.2022

This moon made quite an entrance. Typically, a moonrise is quiet and serene. Taking a few minutes to fully peek above the horizon, Earth's largest orbital companion can remain relatively obscure until it rises high in the nighttime sky.

The Butterfly Nebula from Hubble
21.11.2022

Stars can make beautiful patterns as they age -- sometimes similar to flowers or insects. NGC 6302, the Butterfly Nebula, is a notable example. Though its gaseous wingspan covers over 3 light-years and its estimated...

APOD: 2023 May 3 Б Centaurus A: A Peculiar Island of Stars
3.05.2023

Galaxies are fascinating. In galaxies, gravity alone holds together massive collections of stars, dust, interstellar gas, stellar remnants and dark matter. Pictured is NGC 5128, better known as Centaurus A. Cen A is the fifth brightest galaxy on the sky and is located at a distance of about 12 million light years from Earth.

APOD: 2023 October 31 Б Halloween and the Wizard Nebula
31.10.2023

Halloween's origin is ancient and astronomical. Since the fifth century BC, Halloween has been celebrated as a cross-quarter day, a day halfway between an equinox (equal day / equal night) and a solstice (minimum day / maximum night in the northern hemisphere).

APOD: 2023 November 6 Б Red Aurora over Italy
6.11.2023

What was that red glow on the horizon last night? Aurora. Our unusually active Sun produced a surface explosion a few days ago that sent out a burst of electrons, protons, and more massive charged nuclei.

APOD: 2025 May 14 Б NGC 1360: The Robins Egg Nebula
14.05.2025

This pretty nebula lies some 1,500 light-years away, its shape and color in this telescopic view reminiscent of a robin's egg. The cosmic cloud spans about 3 light-years, nestled securely within the boundaries of the southern constellation of the Furnace (Fornax).