Star Charts

Comets fall toward an observatory on the snow, and each one carries a small star chart: the bright stars of a constellation, joined into its figure. Under the observatory are six chambers that each hold a rocket and the name of a constellation. Tap the chamber with the comet's name, such as Orion for the hunter with three stars in his belt, and its rocket is loaded and fired. The names change chambers every wave, so you learn the shape and not the button. A bright star mode turns it round: a comet names a star, such as Betelgeuse, and you pick the constellation it is in.

Comets carry the star patterns of the constellations. Fire the rocket that holds each one's name, from Orion to all 88.

How to play

Choose a mode: famous shapes, all 88, bright stars, northern sky or southern sky.
Each wave puts six constellations in the chambers. You have 2.5 seconds to read them before the first comet appears.
The lowest comet is the target, with a ring round it. Tap another comet to aim at it instead.
Tap the chamber that names the target's chart. Its rocket is loaded and fired, and the right one destroys the comet.
A wrong name fizzles. The comet drops a step, the launcher jams and says Jammed, and the right name shows under the comet. The jam lasts 1.5 seconds, and 3 seconds from the second wrong name in a row.

Every chart is drawn with north up, as the constellation stands when it is highest in the sky from the northern hemisphere. From the southern hemisphere it looks upside down.

The waves start with the shapes most people know. In famous shapes and all 88 the first wave is always Orion, Cassiopeia, Ursa Major, Leo, Cygnus and Scorpius, and each wave after it brings in a few more. Famous shapes keeps to the 30 best known. All 88 works out from them to every constellation, the large and bright ones first and the small and faint ones last. Northern sky and southern sky keep to the constellations in one half of the sky, starting with the famous shapes of that half. Constellations you got wrong, or that landed, come back with the names in new places.

A wave has more comets than chambers, 7 in the first wave and up to 12 later, so a constellation falls more than once and no chamber can be ruled out. A comet takes 18 seconds to reach the ground in the first wave and a little less in each wave after it, down to 14 seconds.

When the game ends, the game over screen lists every constellation you got wrong or that landed, each beside its chart, with what you picked instead, so you can go over them before you play again. In bright stars it lists each star beside its constellation.

You have three shields, and a comet that reaches the ground costs one. On a keyboard, press 1 to 6 for the chambers as they are numbered, and the left and right arrows to change the target. Escape or Space pauses.

Scoring

The sooner you know the answer, the more a comet is worth.

A comet destroyed with no wrong shot scores 100, plus up to 100 more for how high it still is.
A comet destroyed after a wrong shot showed its answer scores 20.
A wave with no wrong shot and no landing adds 250.

Your five best scores for each mode are saved in this browser, with the wave each game reached. In practice, a comet that lands costs no shield, so the game goes on until you end it from the pause screen. Practice games are not saved.

Which stars are in the game

All 88 constellations the International Astronomical Union recognises, each drawn with its brightest stars, up to 12, and the lines of its figure. The figures follow the IAU and Sky and Telescope charts, through the d3-celestial project, and the credits are on the credits page.

The bright star mode asks about 44 stars: every star of the first magnitude, from Sirius to Shaula, and the best known of the rest, such as Polaris, Algol, Mizar and Alnilam and Alnitak, the two brightest stars of Orion's belt. A comet names the star, and you pick the constellation it is in.

How to remember the constellations

Turn each shape into a picture that goes with its name. Leo's sickle is the lion's mane, Cassiopeia's W is the queen's throne seen from the side, and Cygnus is a swan flying down the Milky Way with its neck stretched out. For a name with no picture, such as Antlia, the air pump, make an image from the sound of the word. See how to create mnemonic images for more ways to build them. The constellations listed on the game over screen are the ones worth making an image for first.

Try our other free memory games, such as Capital Cannon for world capitals or the US Presidents Memory Game for the presidents in order.