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Sky Digest

Tuesday, 16 December 2025 | Default Location
Showing the sky from Greenwich, London. Log in to use your own location.
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Tonight at a Glance

Waning Crescent 9%
Dark window: 17:18 – 06:41 (13 h 22 m)

Planet Highlights

Jupiter mag -2.6 · 27° alt · Gemini Details
GRS transit tonight:
Ganymede Occultation begins
Io Shadow transit begins
Io Transit begins
Io Shadow transit ends
+4 more — Details
Saturn mag 0.9 · 23° alt · Aquarius Details
Rings: Edge-on (rings nearly invisible) (0.7° north face)

Comets

PANSTARRS mag 6.7 · 34° alt · Pegasus Details
bright 2.15 AU Perihelion: Apr 19 (in 18d)

For Beginners (naked eye)

Double Cluster
NGC 869 Open Cluster
mag 4.3

At 21:00 look near the zenith

Perseus
M42
Great Orion Nebula Nebula
mag 4.0

At 21:00 look low in the southeast

Orion
M31
Andromeda Galaxy Galaxy
mag 3.4

At 21:00 look high in the west

Andromeda

Binocular Targets

Mira
68 Cet Variable Star
mag 3.0

At 21:00 look halfway up in the south

Cet
M34
Spiral Cluster Open Cluster
mag 5.5

At 21:00 look near the zenith

Perseus
M33
Triangulum/Pinwheel Galaxy Galaxy
mag 5.7

At 21:00 look high in the southwest

Triangulum

Small Scopes (3–6 inch)

Castor
HIP 36850; Alpha Gem; 66 Gem Double Star
mag 2.0

At 21:00 look halfway up in the east

Gem
NGC 744
Open Cluster
mag 7.9

At 21:00 look near the zenith

Per
M76
Little Dumbbell Nebula Planetary Nebula
mag 10.1

At 21:00 look near the zenith

Perseus
M77
Cetus A or Squid Galaxy Galaxy
mag 8.9

At 21:00 look halfway up in the south

Cetus
R Tri
Variable Star
mag 5.3

At 21:00 look near the zenith

Tri

Big Scopes (8–12 inch)

NGC 1220
Open Cluster
mag 12.0

At 21:00 look near the zenith

Per
C56
NGC 246 Planetary Nebula
mag 10.9

At 21:00 look low in the southwest

Cetus
C23
NGC 891 Galaxy
mag 9.9

At 21:00 look near the zenith

Andromeda
M74
Phantom Galaxy Galaxy
mag 9.4

At 21:00 look high in the southwest

Pisces
NGC 925
Galaxy
mag 10.0

At 21:00 look near the zenith

Tri

The Week Ahead

Tue Wed Thu Fri Sat Sun Mon
🌘 9% 🌘 4% 🌑 1% 🌑 0% 🌑 1% 🌑 3% 🌒 7%

NASA Astronomy Picture of the Day

Andromeda and Sprites over Australia

What’s happening over that tree? Two very different things. On the left is the Andromeda galaxy, an object that is older than humanity and will last billions of years into the future. Andromeda (M31) is similar in size and shape to our own Milky Way Galaxy. On the right is a red sprite, a type of lightning that lasts a fraction of a second and occurs above violent thunderstorms. Red sprites were verified as real atmospheric phenomena only about 35 years ago. The tree in the center is a boab, which may live for as long as a thousand years. Boab trees grow naturally in Australia and Africa and are known for being able to store large amounts of water: up to 100,000 liters. The featured image was captured last month near Derby in Western Australia.

Image credit: JJ Rao — APOD is a service of NASA and Michigan Tech. U.

View on NASA APOD

Space News

Watch live: Artemis II launch

Artemis II, the first crewed mission to the Moon in over 50 years, is scheduled to launch on April 1-2, 2026, carrying four astronauts on a historic 10-day lunar journey.

ESA — 31 Mar 2026

Europe's engines powering Artemis II

Europe's Service Module, equipped with 33 engines, will provide propulsion, power, and life support for the Artemis II spacecraft during its crewed lunar mission.

ESA — 30 Mar 2026

NASA Selects Intuitive Machines to Deliver Artemis Science, Tech to Moon

NASA awarded Intuitive Machines $180.4 million to deliver seven science payloads to the lunar surface as part of the Commercial Lunar Payload Services initiative supporting Artemis.

NASA — 27 Mar 2026

European eyes on Artemis

European engineers and medical specialists will contribute to Artemis II's success through the European Service Module and direct mission support as the crew travels toward the Moon.

ESA — 31 Mar 2026

Plan your session before dark

Use Tonight to find targets, then add them to a Plan so you have a checklist ready when you're outside.

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