Astronomy Picture Of the Day (APOD)APOD: 2023 September 13 Б NGC 4632: Galaxy with a Hidden Polar Ring
Galaxy NGC 4632 hides a secret from optical telescopes. It is surrounded by a ring of cool hydrogen gas orbiting at 90 degrees to its spiral disk. Such polar ring galaxies have previously been discovered using starlight. However, NGC 4632 is among the first in which a radio telescope survey revealed a polar ring.
Galaxy Cluster Abell 370 and Beyond
Some 4 billion light-years away, massive galaxy cluster Abell 370 is captured in this sharp Hubble Space Telescope snapshot. The cluster of galaxies only appears to be dominated by two giant elliptical galaxies and infested with faint arcs.
APOD: 2023 September 11 Б Beautiful Comet Nishimura
This scene would be beautiful even without the comet. By itself, the sunrise sky is an elegant deep blue on high, with faint white stars peeking through, while near the horizon is a pleasing tan.
APOD: 2023 September 10 Б An Annular Solar Eclipse over New Mexico
What is this person doing? In 2012, an annular eclipse of the Sun was visible over a narrow path that crossed the northern Pacific Ocean and several western US states. In an annular solar...
APOD: 2023 September 9 Б Comet Nishimura Grows
Comet Nishimura is growing. More precisely, the tails C/2023 P1 (Nishimura) are growing as it nears the Sun. Discovered only last month, the comet is already near naked eye brightness as it now moves inside the Earth's orbit.
Star Factory Messier 17
Sculpted by stellar winds and radiation, the star factory known as Messier 17 lies some 5,500 light-years away in the nebula-rich constellation Sagittarius. At that distance, this 1/3 degree wide field of view spans over 30 light-years.
The Large Cloud of Magellan
The 16th century Portuguese navigator Ferdinand Magellan and his crew had plenty of time to study the southern sky during the first circumnavigation of planet Earth. As a result, two fuzzy cloud-like objects easily...
APOD: 2023 September 6 Б HESS Telescopes Explore the High Energy Sky
They may look like modern mechanical dinosaurs, but they are enormous swiveling eyes that watch the sky. The High Energy Stereoscopic System (H.E.S.S.) Observatory is composed of four 12-meter reflecting-mirror telescopes surrounding a larger telescope housing a 28-meter mirror.
APOD: 2023 September 5 Б Blue Supermoon Beyond Syracuse
The last full moon was doubly unusual. First of all, it was a blue moon. A modern definition of a blue moon is a second full moon to occur during one calendar month. Since there are 13 full moons in 2023, one month has to have two -- and that month was August.
APOD: 2023 September 4 Б Cygnus: Bubble and Crescent
As stars die, they create clouds. Two stellar death clouds of gas and dust can be found toward the high-flying constellation of the Swan (Cygnus) as they drift through rich star fields in the plane of our Milky Way Galaxy.