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Gemini Card Game

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The GEMMA Podcast

A podcast about Gemini Observatory and its role in the Era of Multi-Messenger Astronomy. Featuring news related to multi-messenger astronomy (MMA), time-domain astronomy (TDA), our visiting instrument program, and more through interviews with astronomers, engineers, and staff both here at Gemini (North and South) and abroad.

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About GCG

Gemini is distributing a card game with unique designs and challenging gameplay.
The Gemini Card Game is a cooperative game for 2 to 4 players who work together to complete science programs over the course of 2 week turns for a semester. Experience the complex decisions required to run a world class observatory and the excitement of contributing to a team as you provide researchers with their precious data and contribute to expanding the knowledge of the Universe.

Game and Graphic Design: André-Nicolas Chené
Development: André-Nicolas Chené, Jerry Brower

Social media: #GeminiCardGame

Download a full deck to print at home!!!

Here are the instructions to create the full 90 card deck:

  • Print one of each of the Instrument cards.
  • Print one of each of the Target cards.
  • Print one of each of the Time cards.
  • Print one of each of the Program cards. Make the Checkouts and the Poor Weather cards the two sides of a same card.
  • For the Weather cards,
    • print 2 "Best" weather cards,
    • print 1 "Great" weather card with a red border,
    • print 4 "Great" weather cards (no red border),
    • print 4 "Good" weather cards,
    • print 4 "Poor" weather cards,
    • print 1 Earthquake card, 1 Storm card, 1 Shutdown GN card and 1 Shutdown GS card.
  • Print one of each of the Role cards. Make :
    • the 1st and the 2nd cards the two sides of a same card,
    • the 3rd and the 4th cards the two sides of a same card,
    • the 5th and the 6th cards the two sides of a same card, and
    • the 7th and the 8th cards the two sides of a same card
  • Optionally, you can print the Reference+Rules cards.

One trick is to print them on paper, cut them, and place them into playcard sleeves. To obtain the right dimensions, you can print 6 cards per US letter size paper in using the portrait orientation. In Acrobat, you can select the option "Multiple" under Page size & Handeling. If available, choose the option "fit to printable area". Use transparent card sleeves to make the double sided cards. Use (or make) different backs for the different decks. Those are the Instruments, Weather and Player (Time, Target and Programs) decks (see the video).


Download the rule book

This is version 1.0 (2019 May 30). Please, read and use this manual. It looks better printed in booklet form! If anything is unclear, or inconsistent, or for any suggestion, please email

Register your deck

Those who register their deck will get a (non frequent, we swear), update of the rules, and alerts when expansion sets and booster packs are available!

Short video tutorial

How does it compare to reality?

Of course, it is just a game. At best, it is a simplistic model of the decision making in place when the Gemini staff is scheduling and observing programs. Also, if 12 rounds is a semester, it means that each round is 2 weeks, and one should expect much more telescope time to be used in real life.

However, Band 1 programs take absolute priority, as they were estimated by peers to be the best use of the telescope time. Band 2 programs are preferable when there are no possibility to observe Band 1 programs. And Band 3 programs are essentially fillers, so good science may be possible when the weather is bad, or when nothing else is available.

Also, deciding on which target to observe, is not always straightforward. Observing a setting target instead of a higher priority one, with the hope to catch that other target later is sometimes the best strategy.

Discover a support astronomer experience that is not too far from what really happens in Hilo and La Serena, and share it with us!

Enter your score!

We are collecting your score in the Gemini Card Game Score Board!  Of course, we are looking for your high score, but also your low ones. And we also want to hear about your lost games! The more we get, the better we can balance future versions of the game (and expansions)! 

Share your experience

You can share your experience with other players and ask questions on the Gemini Card Game forum! (You may have to register before posting.)


Apr 2020: Gemini releases the basic deck design for download!

Errata and rule changes!

Please, concider these changes for the 2019 Basic Deck:

1. Mistake in the scenario card.

Unfortunately, the scenario card was printed with the '2 or 4 player" scenario on both sides... The 3 players scenario should be like this:

2. Extra card in 3 players mode

It is now recommended to add one card in everyone's hand when playing with 3 players. A full hand is therefore 6 cards, unless someone's ability already allows for more cards, in which case it is the number of card for a full hand plus 1 (e.g., 6+1=7).

3. Moving Altair to an instrument does not require action

Altair can now be moved to a 'compatible' instrument (i.e., NIRI, GNIRS or NIFS) without requiring an action from a player. Still, if the instrument is moved to another program, Altair has to be discarded and placed at the bottom of the instrument deck.

Old announcements

Jan 2020: New limited edition booster pack (Good and Bad luck). Available at the 235th AAS meeting.

Nov 2019: Basic deck distributed at the LARIM 2019.

Jun 2019: Basic deck distributed at the 2019 CASCA meeting.

Feb 2019: Basic deck distributed at the K-GMT 2019.

Jan 2019: First release of the game at the 233st AAS meeting.

Nov 2018: Complete game design complete! Ordering the whole bundle for printing in time for the 233st AAS meeting.

Jan 2018: Promo cards are released and distibuted at the 231st AAS meeting. They illustrate the suite of instruments (facility and visiting) available at Gemini for 2018.


We would like to thank Mark Rawlings, Graham Bell, Ryan Berthold, Eileen Gonzalez, Paige Godfrey and the Gemini North Game Club for their precious help with setting up the rules.