SUNSET: 
Find the Phase of the Moon
Learn the phase of the Moon tonight, the day you were born, or on any historical date.
Dawn Dances, Neptunian Nights, and Eclipse Essence
The planets are aligning! The week ahead will feature multiple planetary conjunctions at dawn and great views of Neptune and Triton at nightfall.
Meet the New Interactive Sky Chart!
Our new-and-improved interactive sky chart is here — create and print a customized view of your night sky for any date, time, and location.
This Week's Sky at a Glance, September 8 – 16
Mercury and Mars are passing each other very low in the glow of sunrise, well to the lower left of Venus. Regulus is also with them, as shown in sky scenes here.
Find Jupiter's Moons - Interactive Observing Tool
Use our interactive observing tool to say which of the planet's four largest moons is which.
Transit Times of Jupiter's Great Red Spot
Calculate when the Great Red Spot will cross Jupiter's central meridian — that's the best time to see the famous storm through your telescope.
Find Saturn's Moons: Interactive Observing Tool and App
With help from our interactive JavaScript utility, you can always tell which of Saturn's brightest moons is which.
The Elusive Moons of Uranus
Take the observing challenge: Find as many as five of the brightest moons of Uranus in a large backyard telescope using our interactive observing tool.
Track Triton, Neptune's Largest Moon
Triton, Neptune's largest moon, is a tricky find. Our Triton Tracker observing tool can help users of moderate to large telescopes spot this distant moon.
Tour September's Sky: Saturn Time!
In September's astronomy podcast, you'll learn what's special about the ringed planet Saturn, now visible in the evening sky.
Mars Profiler: Which Side Is Visible?
To compare what you see on Mars with a map, you need to know which side of the planet you're looking at. Our handy Mars Profiler tells you that and more, for any date and time.
Telescope Calculator: How Does Your Telescope Perform?
Use this telescope calculator to tell you how changing out eyepieces and accessories will affect your telescope's performance.
This Week's Sky at a Glance, September 1 – 9
The waxing gibbous Moon is appears equally distant from Saturn, well to its right, and Altair, high to its upper left.
Asteroid Florence Pays Earth a Visit
Florence, one of the largest Earth-approaching asteroids, gets close enough to see in a small telescope this week and next. Here's how to find it.
Satellite Tracking Tool: Track the ISS & Hubble
The International Space Station passes over virtually all of Earth's populated areas, and you can spot it easily with your eyes alone — if you know where and when to look for it.
Satellite Transit Tool: Spot ISS Transits of the Sun and Moon
The International Space Station often passes close to the Moon, Sun, and naked-eye planets. Use this tool to plan viewing these close encounters.
This Week's Sky at a Glance, August 25 – September 2
Look low in the west in twilight for the waxing crescent Moon. It forms a triangle with Jupiter and Spica below it.
Stargazer's Corner: Adventures Under the Night Sky
Low-Tech Astrophotography: Game Boy Camera
Inspired by his love of astronomy and struck by the unique ways in which the Game Boy Camera had been harnessed, Alex Pietrow took to the internet to see what photos of space it had taken. When he found none, he took his own.
This Week's Sky at a Glance, August 18 – 26
The Milky Way runs from Sagittarius in the south, up and left across Aquila and the Summer Triangle very high in the east, and down through Cassiopeia to Perseus low in the north-northeast.
Solar Eclipse Activities for Kids and Families
Enrich the eclipse experience — especially the long, partial phases — with solar eclipse activities for the young and young at heart.
