The constellation quiz

日本語

The demo's quiz.html shows a chart of the stars around one constellation with no name written on it, and six names in a row under it. Choose one: the right one turns green; a wrong one shakes (not with reduced motion) and the page says what it was. Next question asks another. The page keeps the score, the streak and, under the question, each constellation you missed with its picture and a link to its page, for as long as it is open.

• Style makes it easier or harder: Plain (the stars and nothing else, the hardest), Stars and lines (the constellation's figure as well) or Annotated (the figure, the IAU boundary, and the names of the neighbouring constellations, never the one asked).
• Level is which constellations it asks: Bright 12 (the twelve whose figure stars give the most light), Bright 30, or All 88. The five wrong names are drawn from the same level.
• Culture asks about another sky: Japanese (the 88 constellations as Japan names and joins them, and its traditional star patterns, with at least three stars in the catalogue and two lines) or Chinese mansions (the Twenty-Eight Mansions with at least three of their stars in the catalogue; the other figures of the Chinese sky are a later step). The names are the data's own: Japanese or English for the Japanese sky (an old pattern with its reading, 昴 (すばる)); Traditional characters for the mansions, with the English name beside them where the data has one and the pinyin where it has not, and the characters alone on the Japanese page. The levels are that sky's own (All 21), the chart draws that culture's lines, Annotated is not offered (its borders and neighbours are the Western sky's), and the address keeps culture (japanese or chinese; Western is the default).
• Sky limits the quiz to what a reader can see: North or South (seen from 40 degrees north or south), and a month, or Any month for the whole year. A constellation counts when more than half of the stars of its figure are more than 10 degrees above the horizon at 21:00 on the 15th of the month, worked out with the package's horizontal; the Southern Cross is never asked in the north, Orion not on a July evening. The level is then taken from that sky, and the six names come from it. The address keeps hemisphere (north or south) and month (1 to 12).
• Put it in your page: the panel under the quiz gives the code for a frame, <iframe src=".../embed-quiz.html?level=88&style=lines&kid=1">, at 320, 480 or 640 wide. The embed page is the quiz without its controls: its address chooses style, level, kid=1, hemisphere, month and lang=ja, it writes nothing back to its address, and the question is never in the code.
• The five wrong names are the ones easy to mix up with the answer: up to three of its neighbours in the sky, then constellations made in the same years, then the rest of the level. The arrow keys move across the six names (up and down by a row), and 1 to 6 answer.
• Kid mode (a button beside the level) makes every button at least 56 px tall, the six names bigger still, and says things more simply ("Which star picture is this?", "Yes! It is Orion!", Easy, Medium, Hard). It is kept in the address as kid=1, and it never names the answer before you have chosen.
• The address keeps style (lines or annotated; plain is the default), level (30 or 88; the bright 12 is the default) and q, the question: the constellation's place in the list of the 88, from 1 (quiz.html?q=60&level=88), so a reload or a shared link asks the same question (with the same answer, but its five wrong names are drawn again). The address never has the constellation's name, but it is not a secret: a number can be looked up. A hand-written c=Ori is read too, to ask a chosen constellation. It is a quiz for the classroom and the family, not a test.

The chart is the package's own chart() drawn once for each question, centred on centreOfConstellation and zoomed to fit the figure. Nothing moves and nothing is drawn while you think. The keys 1 to 6 choose a name, and the focus goes to Next question after an answer and to the first name after that. It works on a phone, the six names in two or three columns, and the names are in Japanese on the Japanese page.