The Red Rectangle
2.11.1995

The unusual geometry of this stellar nebula creates somewhat of a mystery. At the nebula's center is a young binary star system that probably created the nebula, but how? This type of nebula shows a "bipolar flow" which carries a significant amount of mass away from the central stars.

Perseid Meteor, Red Sprites, and Nova RS Oph
16.08.2021

This was an unusual sky. It wasn't unusual because of the central band the Milky Way Galaxy, visible along the image left. Most dark skies show part of the Milky Way. It wasn't unusual because of the bright meteor visible on the upper right.

Moon, Venus, Jupiter, Phoenix
25.08.1998

Before a relaxing sunrise, the sky begins to glow with unusual delights. Such was the view from Papago Park in Phoenix, Arizona this April. The glittering objects visible in this photograph are, from lower left to upper right: Phoenix, our Moon, Venus, and Jupiter. Such proximity is somewhat unusual.

Peculiar Elliptical Galaxy Centaurus A
30.06.2014

What's happened to the center of this galaxy? Unusual and dramatic dust lanes run across the center of elliptical galaxy Centaurus A. These dust lanes are so thick they almost completely obscure the galaxy's center in visible light.

APOD: 2026 January 5 Б The Red Rectangle Nebula from Hubble
5.01.2026

How was the unusual Red Rectangle nebula created? At the nebula's center is an aging binary star system that surely powers the nebula but does not, as yet, explain its colors. The unusual...

Starburst Ring in Galaxy NGC 1317
11.12.1996

Where do stars form? A typical place is an area of dense nebular gas common to arms in spiral galaxies. Sometimes, however, a burst of star formation can occur with unusual geometry. Nearby galaxy NGC 1317 shows such an unusual ring of star formation surrounding its barred nucleus.

APOD: 2025 March 4 Б A Quadruple Alignment over Italy
4.03.2025

Why does this Moon look so unusual? A key reason is its vivid red color. The color is caused by the deflection of blue light by Earth's atmosphere -- the same reason that the daytime sky appears blue. The Moon also appears unusually distorted.

APOD: 2024 March 11 Б A Full Plankton Moon
11.03.2024

What glows in the night? This night featured a combination of usual and unusual glows. Perhaps the most usual glow was from the Moon, a potentially familiar object. The full Moon's nearly vertical descent results from the observer being near Earth's equator.

APOD: 2025 November 10 Б Micro Moon vs Super Moon
10.11.2025

What was so super about Wednesday's supermoon? Last week, a full moon occurred that appeared slightly larger and brighter than usual. The reason is that the Moon's fully illuminated phase occurred within a short time from perigee - when the Moon was its closest to the Earth in its elliptical orbit.

Grey Sun Seething
8.01.1997

The Sun's surface is not smooth. It has thousands of bumps called granules and usually a few dark depressions called sunspots. Each of the numerous granules is the size of an Earth continent, but much shorter lived.