One of the most recognizable constellations in the sky.
M31
Andromeda GalaxyGalaxy
Magnitude3.4
Angular Size190' × 60'
Distance2.5 million light-years
CoordinatesRA 0h 42m, Dec +41°
The nearest major galaxy to the Milky Way.
1P/Halley
Halley's CometPeriodic
Orbital Period~76 years
Perihelion Distance0.59 AU
Last PerihelionFeb 9, 1986
Next ReturnJul 28, 2061
The most famous comet in history.
Venus
Terrestrial Planet
Diameter12,104 km
Distance0.72 AU
Orbital Period225 days
Rotation243 days
Moons0
Often called Earth's twin.
Pluto
134340 PlutoDwarf Planet
Diameter2,377 km
Orbital Period248 years
Distance from Sun30-49 AU
Moons5
Discovered1930
Once considered the ninth planet.
Once Around the Night Sky
About
An interactive visualizer for
Paul Fellows'
excellent "Once Around" series of astronomy YouTube videos.
Explore the night sky and discover the celestial objects featured in the series.
Data Sources
Stars: Hipparcos Catalogue (~118,000 stars) with fallback to Yale Bright Star Catalog
Planets: VSOP87 planetary theory for high-precision positions
Moon: Simplified lunar ephemeris based on Meeus's Astronomical Algorithms
Constellations: IAU constellation boundaries with stick figures