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Mars with Aldebaran and the Pleiades, mid-February 2023

This Week's Sky At a Glance

This Week's Sky at a Glance, February 10 – 19

Comet ZTF is fading and receding into the distance. On the other hand, it's now conveniently placed high overhead in early evening in a moonless sky; the waning Moon doesn't rise until late.

cluster of various galaxies


The Universe Is Too Smooth By Half

Results from a complex new analysis support cosmologists’ suspicions that something is missing from our understanding of the universe.

An artist illustration of the Quaoar system in front of a background of white stars. Central in the figure sits a brownish planet. This is Quaoar, a dwarf planet in the outer Solar System. At a distance of about five times its radius sits a ring. This ring is made up out of small grey pieces of debris. At twice the distance of the ring, to the left of Quaoar, sits its moon Weywot. Weywot looks about a sixth the size of Quaoar but has the same brownish colour. To the right of this system, we see a bright star. This star is bigger than the background stars and represents the distant Sun

Solar System

Astronomers Discover Unexpected Ring around Distant Dwarf Planet 

There’s a strangely large-diameter ring around the outer solar system world Quaoar.

Mars, Aldebaran, and the Pleiades in late twilight, Feb. 10, 2023

Celestial News & Events

This Week's Sky at a Glance, February 3 – 12

Comet ZTF is still near its brightest, moonlight and all. Around the Big and Little Dog Stars, trace out the stick-figure patterns of the big and little dogs. A ghostly unicorn haunts the inside of the Winter Triangle.

Terence Dickinson

Astronomy and Society

Terence Dickinson (1943 – 2023)

Terence Dickinson, Canadian astronomer and author of numerous popular books on astronomy, has passed away.

Lucy spacecraft next to shiny rock on black field

Astronomy in Space with David Dickinson

Lucy Mission Has a New Asteroid to Fly By

NASA’s Lucy mission now has a new first target of opportunity, a main-belt asteroid it will visit this November.

Comet ZTF (C/2022) and Mt. Etna


Understanding the Tails of Comet ZTF (C/2022 E3)

We explore Comet ZTF's remarkable trio of tails and share the latest news and photos.

Orion and nearby constellations

Sky Tour Astronomy Podcast

February: Winterʼs Dazzling Stars

February 4th marks the midway point between Decemberʼs solstice and the March equinox. Celebrate that celestial milestone by getting outside to gaze in awe at the amazing array of bright stars youʼll find overhead on February evenings.

Jupiter, Ganymede, Europa and double shadows, March 25, 2019

Solar System

Astronomers Find a Dozen More Moons for Jupiter

The discovery of a dozen new moons for Jupiter makes the king of planets the king of moons, too — at least for now.

Comet ZTF E3 dust tail


See Comet ZTF (C/2022 E3) Dash Between Big and Little Dippers

Forget the hype and go outside to enjoy the real thing — a relatively bright comet you can see in binoculars from a dark sky.

This Week's Sky At a Glance

This Week's Sky at a Glance, January 27 – February 5

Comet ZTF is at its best this week — but every night moonlight encroaches on the scene until a later and later hour. Along the way, the Moon occults Mars for the southern U.S. and again forms isosceles triangles with naked-eyestars.

2023 BU close approach

Celestial Objects to Observe

Tiny Asteroid 2023 BU to Miss Earth

A recently discovered asteroid will pass exceptionally close to Earth on January 26th. Here's how to see it. Also, Comet ZTF (C/2022 E3) is brightening nicely, with three tails visible in binos.

Zoom ins on massive galaxy cluster show tiny red dots, distant galaxies that resemble nearby


New Observations Reveal Galaxies Near and Far

Astronomers at this month's big winter conference explored intriguing small galaxies at various points in cosmic history.

Intracluster light with Hubble


Hubble and Webb Image Galaxies’ Lost Stars

Deep images of galaxy clusters reveals the light of wandering stars. What set these stars free from their hosts?

Dark planet with translucent atmosphere in front of bright star


JWST Investigates an Exoplanet "Corgi"

The James Webb Space Telescope has found the tiny tail of a close-in exoplanet that's losing its atmosphere.

Infographic showing increasing skyglow and disappearing stars

Astronomy and Society

Light Pollution Is Increasing Even Faster Than We Realized

The average brightness of the night sky is increasing by 10% every year, making the stars less visible.

Crescent Moon passing Venus and Saturn in conjunction, Jan. 22-23, 2023

This Week's Sky At a Glance

This Week's Sky at a Glance, January 20 – 29

Venus and Saturn have a close conjunction in twilight. Comet ZTF heads into its best week. And Betelgeuse overtakes Sirius ever earlier in the night.

Celestial News & Events

See a Giant Sunspot!

If you have a solar filter, check out the sunspot group AR 3190 that's crossing the solar disk this week.


Solar System

The Moons of the Solar System

Not so long ago, astronomers thought only a few dozen moons orbited the planets of our solar system. Today, the total count tops 170!

Green arc floats above the Andromeda Galaxy


Amateur Astronomers Find Glowing Gas Arc Near Andromeda

An arc that glows green thanks to doubly ionized oxygen appears near the Andromeda Galaxy in a photo obtained by amateur astronomers.