Interactive Tools

Space calculators

Interactive tools for exploring space and astronomy. More calculators are on the way.

WEIGHT

Weight on Other Planets

See what you'd weigh on Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune.

Quick • Fun

DISTANCE

Light-Time & Distance Calculator

Real light-travel time between planets and stars, plus a custom km/AU/light-year/parsec converter.

Quick • Real data

MOON

Moon Phase Calculator

Real synodic lunar phase for any date, with astrophotography advice and upcoming phase-change projections.

Quick • Any date

SPACE WEATHER

CME Arrival Time Calculator

Estimate a coronal mass ejection's transit time from the Sun to Earth based on its launch speed.

Quick • Estimate

FUN

Interstellar Text Message Delivery Tracker

How long would a radio message take to reach Mars, Jupiter, or Proxima Centauri?

Quick • Mind-bending

FUN

Cosmic Speed Multiplier Highway

If you drove there non-stop, how long would it take to reach the Moon or Pluto?

Quick • Road trip

STARGAZING

Bortle Sky Quality Checklist

What can you actually expect to see at your sky's Bortle darkness class?

Checklist

TELESCOPE

Telescope Magnification Matcher (Quick)

A fast, simple magnification check — just focal length and eyepiece size, nothing more.

Quick • Beginner

TELESCOPE

Telescope Magnification & Aperture Calculator (Full)

The complete optics calculator — magnification, max useful power limit, exit pupil, and an over-magnification warning.

Full optics

TELESCOPE

Maximum Clear Magnification Safeguard

Find your telescope's real useful magnification ceiling before the image blurs.

Quick • Safeguard

STARGAZING

Dark Sky Observing Window Finder

Find the peak dark, twilight-free window between sunset and sunrise.

Tonight

METEORS

Predictive Meteor Shower Hourly Rate Adjuster

Adjust a shower's published rate for real-world cloud cover and moonlight.

Quick • Real rates

ASTROPHOTO

Light Pollution Exposure Estimator

A starting point for astrophotography sub-exposure length based on your Bortle class.

Quick • Camera

FUN

Your Age & Weight on Other Worlds

Real surface gravity ratios and orbital periods for Mars, Jupiter, and the Moon.

Quick • Personal

MOON

Next Lunar Phase Countdown Chronometer

Real synodic moon phase math — days until the next New, Quarter, or Full Moon.

Countdown

AURORA

Aurora Road Trip Distance Estimator

How far north do you need to drive from your city to reach the current aurora boundary?

Quick • Road trip