2e:null 2f:["$","title",null,{"children":"When the full moon will rise for you | Toph Tucker | Observable"}] 34:T408,// Generated by Claude function generateICS(events) { const formatDate = (date) => new Date(date).toISOString().replace(/[-:]/g, "").split(".")[0] + "Z"; const escapeText = (text) => String(text) .replace(/\\/g, "\\\\") .replace(/;/g, "\\;") .replace(/,/g, "\\,") .replace(/\n/g, "\\n"); const lines = [ "BEGIN:VCALENDAR", "VERSION:2.0", "PRODID:-//My App//EN", "CALSCALE:GREGORIAN", "METHOD:PUBLISH" ]; for (const event of events) { const uid = `${Date.now()}-${Math.random().toString(36).slice(2)}`; const dtStamp = formatDate(new Date()); const dtStart = formatDate(event.startTime); lines.push( "BEGIN:VEVENT", `UID:${uid}`, `DTSTAMP:${dtStamp}`, `DTSTART:${dtStart}`, `DTEND:${dtStart}`, // zero duration: DTEND === DTSTART `SUMMARY:${escapeText(event.description)}`, "END:VEVENT" ); } lines.push("END:VCALENDAR"); return lines.join("\r\n") + "\r\n"; // ICS spec requires CRLF line endings }35:[] 32:{"id":"0323cd99ef6dd39c","slug":"when-the-full-moon-will-rise-for-you","title":"When the full moon will rise for you","thumbnail":"b40b108ed127955eb16367940c5a65fbbeb0ac427239148d167a8686e3b56f5a","access_level":"public","create_time":"$D2026-03-05T23:39:52.881Z","update_time":"$D2026-03-06T01:13:16.464Z","view_time":null,"first_public_time":"$D2026-03-06T00:57:36.840Z","has_unpublished_edits":null,"fork":false,"stars":0,"starred":false,"owner":{"type":"team","id":"97290e936c339d8e","login":"tophtucker","name":"Toph Tucker","avatar_url":"https://avatars-next.observableusercontent.com/3706c31a8f9c59bb716c022c04b9c073144cd1368b78ac85f49139be6c93c34e","tier":"pro_2026"},"version":284,"publish_version":null,"role":null,"authored":false,"authors":[{"type":"individual","id":"0bb2842b01e0c652","login":"tophtucker","name":"Toph Tucker","avatar_url":"https://avatars-next.observableusercontent.com/3706c31a8f9c59bb716c022c04b9c073144cd1368b78ac85f49139be6c93c34e","tier":null}],"members":[{"type":"individual","id":"0bb2842b01e0c652","login":"tophtucker","name":"Toph Tucker","avatar_url":"https://avatars-next.observableusercontent.com/3706c31a8f9c59bb716c022c04b9c073144cd1368b78ac85f49139be6c93c34e","tier":null,"role":"editor"},{"type":"team","id":"97290e936c339d8e","login":"tophtucker","name":"Toph Tucker","avatar_url":"https://avatars-next.observableusercontent.com/3706c31a8f9c59bb716c022c04b9c073144cd1368b78ac85f49139be6c93c34e","tier":"pro_2026","role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":0,"collection":{"id":"d6d8f3dc44d16858","slug":"utilities","title":"Utilities","owner":{"id":"97290e936c339d8e","login":"tophtucker","name":"Toph Tucker"}},"type":"notebook","body":{"title":"When the full moon will rise for you","cells":[{"id":0,"value":"# When the full moon will rise for you\nThe other day I missed a great full moon rising because I didn’t think to look at the right time. I want a calendar of when to look outside for the full moon rising, and where to look.\n\nThis notebook will request access to your location and then show you the next year of full moon rises and where to look in the sky. Then you can download the iCalendar (ICS) file and import it into your calendar of choice.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":114,"value":"\n ${fullRises.map(d => htl.html`\n \n \n \n \n \n \n \n \n `)}\n

${d3.timeFormat(\"%a.\")(d.rise)}

${d3.timeFormat(\"%b.\")(d.rise)}

${d3.timeFormat(\"%-d\")(d.rise)}

${d3.timeFormat(\"%-I:%M %p\")(d.rise)}

look

${azimuthToCompass(d.azimuth)}

\n","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":217,"value":"{\n const events = fullRises.map(d => ({startTime: d.rise, description: `Look ${azimuthToCompass(d.azimuth)} for the full moon`}));\n const ics = generateICS(events);\n const blob = new Blob([ics], { type: 'text/calendar;charset=utf-8' });\n return DOM.download(blob, \"fullmoons.ics\", \"Download iCalendar file\")\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":272,"value":"Caveats: I don’t know how Volodymyr Agafonkin’s [SunCalc](https://github.com/mourner/suncalc) defines “rise”; is it when the upper tip of the moon breaks the idealized horizon? [WolframAlpha](https://www.wolframalpha.com/input?i=next+full+moon) seems to run about 11 minutes later than these numbers. Assuming you have some buildings or hill on the horizon, you might want to actually look at the sky more like half an hour _after_ the listed time. I’ll try to pay attention to the next one and calibrate this.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":232,"value":"---\n## Appendix\n\nFirst we request your location:","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":8,"value":"position = new Promise((resolve, reject) => navigator.geolocation.getCurrentPosition(resolve, reject))","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":237,"value":"Load Volodymyr Agafonkin’s [SunCalc](https://github.com/mourner/suncalc) library:","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":16,"value":"SunCalc = require(\"suncalc\")","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":55,"value":"Get the next year of moon rises:","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":3,"value":"rises = d3.timeDay\n .range(new Date(), d3.timeDay.offset(new Date(), 365))\n .map((day) => {\n const { latitude, longitude } = position.coords;\n const { rise } = SunCalc.getMoonTimes(day, latitude, longitude);\n const { fraction } = SunCalc.getMoonIllumination(rise);\n const { azimuth, altitude } = rise\n ? SunCalc.getMoonPosition(rise, latitude, longitude)\n : {};\n return {\n rise,\n fraction,\n azimuth,\n altitude\n };\n })\n .filter((d) => d.rise) // I guess the moon doesn’t rise every day","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":59,"value":"Get the local maxima above 98% illuminated, which I take to be full:","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":63,"value":"fullRises = rises.filter(\n ({ fraction }, i, arr) =>\n fraction > 0.98 &&\n fraction > arr[i - 1]?.fraction &&\n fraction > arr[i + 1]?.fraction\n)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":247,"value":"Convert azimuth (in SunCalc, starting at 0 in the south and proceeding to the west in radians) to compass bearings:","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":97,"value":"function azimuthToCompass(azimuth) {\n const compass = [\n \"N\",\"NNE\",\"NE\",\"ENE\",\n \"E\",\"ESE\",\"SE\",\"SSE\",\n \"S\",\"SSW\",\"SW\",\"WSW\",\n \"W\",\"WNW\",\"NW\",\"NNW\"\n ];\n const sectorWidth = (2 * Math.PI) / compass.length;\n const index = Math.round(((azimuth + Math.PI) % (2 * Math.PI)) / sectorWidth) % compass.length;\n return compass[index];\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":259,"value":"Then generate the ICS (iCalendar) string. I didn’t love the look of any of the JavaScript libraries for this, and I don’t need many properties, so this is a one-off function by Claude that just takes an array of objects with startTime and title (which I guess iCalendar calls “SUMMARY”):","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":206,"value":"$34","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W35","stdlib":"1","titling":"auto"}} 33:"$32:body"