ScienceExplain Like I'm 5Beginner
Reading the Night Sky, a free science course on Tomo

Reading the Night Sky

Transform an overwhelming canopy of stars into a legible cosmic map. Learn to navigate constellations, spot wandering planets, and read the secrets written in starlight using just your eyes.

Like Duolingo, but for Reading the Night Sky. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.

A short one: 12 levels across 2 sections, about 24 minutes end to end, roughly 5 days at five minutes a day. It moves through Finding Your Bearings and Decoding Cosmic Light. It starts from scratch.

12 bite-size levelsAbout 5 minutes each

Free forever · No credit card · iPhone & Android

Stella the Starling, the guide who teaches the Reading the Night Sky course
Reading the Night Sky
with Stella the Starling
12
Levels
2
Sections
5
Min/day
What you'll learn

Key ideas in Reading the Night Sky

  • A closed fist held out at arm's length covers about 10 degrees of sky
  • Stacking fist widths allows you to measure angular distances between ground landmarks and stars
  • Your arm must be fully extended for hand-based sky measurements to be consistent
  • The Big Dipper's bowl has two outer stars known as the pointers
  • Tracing a straight line upward through those two stars leads directly to Polaris
  • Following the pointer stars is the standard starting jump for northern sky-hopping
  • Polaris is only a moderately bright star, ranking around the 50th brightest in the night sky
  • Polaris appears stationary because it sits almost directly above Earth's north rotational axis
  • All other northern stars appear to rotate in circles around Polaris over the course of the night
  • Human eyes take roughly twenty to thirty minutes of darkness to reach full night sensitivity
  • A brief flash of white light immediately ruins dark adaptation and resets the timer
  • Red light does not disrupt the chemical adaptation of your night-vision rod cells
  • Astronomical magnitude works in reverse, where lower or negative numbers mean brighter objects
  • Negative magnitudes represent the brightest celestial sights like bright planets or Sirius
  • Magnitude +6 is roughly the faintest limit the human eye can see under clear, dark skies
  • Stars appear as microscopic pinpricks easily disrupted by moving air in our atmosphere
Why not just Google it

You've tried the other tabs

Wikipedia

Thirty open tabs. Four facts you actually kept.

YouTube

You watched. You nodded. By Sunday it was gone.

ChatGPT

One answer, then back to scrolling.

Online courses

Eight weeks. You meant to finish. You didn't.

Tomo gives Reading the Night Sky the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.

Try a question

Here's what playing it feels like

A real question from this course. Take your best guess.

Measuring the Sky with Hands

How can you use your fist to measure the distance from the ground up to a star?

Get it right to open this lesson and 11 more in the app.

Course map

Where Reading the Night Sky takes you

  1. 1

    Finding Your Bearings

    • Star-Hopping from the Ground Up
    • Telling Planets Apart from Stars
  2. 2

    Decoding Cosmic Light

    • What Star Color and Distance Reveal
    • The Geometry of the Moon and Shadows

2 sections · 4 units · 12 levels. Built to play, not to enroll.

New

Tomo is in ChatGPT

Tomo is also a ChatGPT plugin: the same playable courses, built and played inside your chat.

Add Tomo to ChatGPT
How it's taught

You pick the voice

This course
Explain Like I'm 5

Reading the Night Sky is taught in the Explain Like I'm 5 style: no big words. promise.. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.

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Start free

Start Reading the Night Sky today.

Download Tomo, search Reading the Night Sky, and play your first lesson in under a minute.