2b:null 2c:["$","title",null,{"children":"Venus Orbital Elements Toolkit | notanaccent | Observable"}] 31:T4d7,propagation = { let me = [0, 0, 0]; const time = new Date(playback); const gstime = satellitejs.gstime(time); const propagate = satellitejs.propagate(satellite, time).position; if (true) { const geodetic = satellitejs.eciToGeodetic(propagate, gstime); const long = satellitejs.degreesLong(geodetic.longitude); const lat = satellitejs.degreesLat(geodetic.latitude); me = [propagate.x * 1e3, propagate.y * 1e3, propagate.z * 1e3]; //[long, lat, geodetic.height * 1000]; const lastCrumb = mutable trail.length ? mutable trail[mutable trail.length - 1] : me; const lastGeodetic = satellitejs.eciToGeodetic( { x: lastCrumb[0], y: lastCrumb[1], z: lastCrumb[2] }, gstime ); const lastLong = satellitejs.degreesLong(lastGeodetic.longitude); const lastLat = satellitejs.degreesLong(lastGeodetic.latitude); const dAngle = (Math.abs(lastLong - long) % 180) + (Math.abs(lastLat - lat) % 180); if (!mutable trail.length || dAngle > 1) { if (mutable trail.length > 360) { mutable trail = mutable trail.slice(1).concat([me]); } else { mutable trail = mutable trail.concat([me]); } } mutable iteration += 1; } return me; }32:T51b,layers = { const layers = []; const VENUS_RADIUS_METERS = 6.0518e6; layers[0] = new deck.SimpleMeshLayer({ id: "earth", data: [0], mesh: new window.luma.SphereGeometry({ radius: VENUS_RADIUS_METERS, nlat: 18, nlong: 36 }), texture: FileAttachment("venus_texture_2k.jpg").image(), coordinateSystem: deck.COORDINATE_SYSTEM.CARTESIAN, getPosition: [0, 0, 0], getOrientation: [0, 90 + venusAngle, 270], getColor: [100, 100, 100], pickable: true // stops picking through the earth }); layers[1] = new deck.ScenegraphLayer({ id: "satellite", data: [propagation], scenegraph: await FileAttachment("rcm@3.glb").url(), getPosition: (d) => d, getOrientation: (d) => [-90, 0, 0], coordinateSystem: deck.COORDINATE_SYSTEM.CARTESIAN, sizeScale: 6e3, _lighting: "pbr" }); layers[2] = new deck.LineLayer({ id: "path", data: trail, getWidth: 2, getSourcePosition: (d, { index, data }) => (index ? data[index - 1] : d), getTargetPosition: (d) => d, getColor: (d, { index, data }) => [ 65, 185, 63, (255 * index) / data.length ], coordinateSystem: deck.COORDINATE_SYSTEM.CARTESIAN, widthMinPixels: 2 }); deckgl.setProps({ layers }); return layers; }33:Tb05,class EarthController extends deck._GlobeController { // Zoom to/from the earth's center rather than the current mouse position. _zoomWithoutPan(scale) { const state = this.controllerState; const startZoom = state.getViewportProps().zoom; let zoom = startZoom + Math.log2(scale); const { maxZoom, minZoom } = state.getViewportProps(); zoom = this.clamp(zoom, minZoom, maxZoom); const zoomedViewport = state.makeViewport({ ...state.getViewportProps(), zoom }); return state._getUpdatedState({ ...zoomedViewport }); } _onWheel(event) { if (!this.scrollZoom) { return false; } event.srcEvent.preventDefault(); const pos = this.getCenter(event); if (!this.isPointInBounds(pos, event)) { return false; } const { speed = 0.01 } = this.scrollZoom === true ? {} : this.scrollZoom; const { delta } = event; // Map wheel delta to relative scale let scale = 2 / (1 + Math.exp(-Math.abs(delta * speed))); if (delta < 0 && scale !== 0) { scale = 1 / scale; } const newControllerState = this._zoomWithoutPan(scale); this.updateViewport(newControllerState, this._getTransitionProps(), { isZooming: true, isPanning: true }); return true; } _onDoubleTap(event) { if (!this.doubleClickZoom) { return false; } const pos = this.getCenter(event); if (!this.isPointInBounds(pos, event)) { return false; } const isZoomOut = this.isFunctionKeyPressed(event); const newControllerState = this._zoomWithoutPan(isZoomOut ? 0.5 : 2); this.updateViewport(newControllerState, this._getTransitionProps(), { isZooming: true, isPanning: true }); this.blockEvents(100); return true; } _onKeyDown(event) { if (!this.keyboard) { return false; } let zoomSpeed = (this.keyboard === true ? undefined : this.keyboard?.zoomSpeed) || 2; const funcKey = this.isFunctionKeyPressed(event); zoomSpeed = funcKey ? zoomSpeed * 2 : zoomSpeed; let newControllerState; const interactionState = {}; switch (event.srcEvent.code) { case "Minus": newControllerState = this._zoomWithoutPan(1 / zoomSpeed); interactionState.isZooming = true; break; case "Equal": newControllerState = this._zoomWithoutPan(zoomSpeed); interactionState.isZooming = true; break; default: return super._onKeyDown(event); } this.updateViewport( newControllerState, this._getTransitionProps(), interactionState ); return true; } clamp(x, min, max) { // https://github.com/uber-web/math.gl/blob/master/modules/web-mercator/src/math-utils.ts return x < min ? min : x > max ? max : x; } }34:[{"id":"c8555ec0f96800012a7a14a04c52d8852a7e1ae476bfb238d82906487208972ea51b5b256c677eea79342b254dc82778ba25a7f646460d1689f7e68a83e48dd8","href":"https://static.observableusercontent.com/files/c8555ec0f96800012a7a14a04c52d8852a7e1ae476bfb238d82906487208972ea51b5b256c677eea79342b254dc82778ba25a7f646460d1689f7e68a83e48dd8","name":"rcm@3.glb","type":"model/gltf-binary","lastModified":1685490948510.417,"size":212504},{"id":"92abbf6411ea74670ff49fb4a7503425ed4f5268bbec3212bd6203416aeec92aef58ffbcef72e1e8492f88da343034b0192dbc2f0125f6c86c34bd8e52899bcb","href":"https://static.observableusercontent.com/files/92abbf6411ea74670ff49fb4a7503425ed4f5268bbec3212bd6203416aeec92aef58ffbcef72e1e8492f88da343034b0192dbc2f0125f6c86c34bd8e52899bcb","name":"venus_texture_2k.jpg","type":"image/jpeg","lastModified":1685503823056.305,"size":989913}] 2f:{"id":"7981a2596137f7da","slug":"venus-orbital-elements-toolkit","title":"Venus Orbital Elements 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Orbital Elements Toolkit","cells":[{"id":0,"value":"md`# Venus Orbital Elements Toolkit\n[reference](https://www.amsat.org/keplerian-elements-tutorial/)`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":4212,"value":"viewof T0 = Inputs.datetime({\n label: \"Epoch (local)\",\n value: +getQueryParam(\"T0\") || Date.now()\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":4447,"value":"viewof I0 = {\n return Inputs.range([0, 180], {\n label: \"Orbital Inclination (degrees)\",\n value: +getQueryParam(\"I0\") || 0,\n format: (d) => d.toFixed(3)\n });\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":4445,"value":"viewof RAAN = {\n return Inputs.range([0, 360], {\n label: \"Right Ascension of Ascending Node\",\n value: +getQueryParam(\"RAAN\") || 0,\n format: (d) => d.toFixed(3)\n });\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":4449,"value":"viewof W0 = {\n return Inputs.range([0, 360], {\n label: \"Argument of Perigee (degrees)\",\n value: +getQueryParam(\"W0\") || 0,\n format: (d) => d.toFixed(3)\n });\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":4528,"value":"viewof E0 = {\n return Inputs.range([0, 0.9999999], {\n label: \"Eccentricity\",\n value: +getQueryParam(\"E0\") || 0.745,\n format: (d) => d.toFixed(7)\n });\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":4532,"value":"viewof M0 = {\n return Inputs.range([0, 360], {\n label: \"Mean Anomaly (degrees)\",\n value: +getQueryParam(\"M0\") || 0,\n format: (d) => d.toFixed(3)\n });\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":4531,"value":"viewof N0 = {\n return Inputs.range([1, 16], {\n label: \"Mean Motion (revolutions per day)\",\n value: +getQueryParam(\"N0\") || 1,\n format: (d) => d.toFixed(8),\n transform: Math.sqrt\n });\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":4537,"value":"viewof N1 = {\n return Inputs.range([-1e-4, -1e-9], {\n label: \"Drag (revolutions per day per day)\",\n value: +getQueryParam(\"N1\") || -1e-9,\n format: (d) => d.toExponential(4),\n transform: Math.exp\n });\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":4559,"value":"tle = {\n //https://en.wikipedia.org/wiki/Two-line_element_set\n const epochYear = T0.getFullYear().toString().slice(-2);\n const epochDay = (\n (T0 - new Date(T0.getFullYear() + \"\")) /\n 24 /\n 60 /\n 60 /\n 1000\n ).toFixed(8);\n\n const b = (N1 * 10).toExponential(4);\n\n function pad(str, len, fill = \"0\") {\n while (str.length < len) {\n str = fill + str;\n }\n return str;\n }\n\n return `1 12345U 22000A ${pad(epochYear, 2)}${pad(\n epochDay,\n 12\n )} .00000000 00000-0 ${\n b.slice(0, 2) + b.slice(3, 7) + b.slice(8, 10)\n } 0 9990\n2 12345 ${pad(I0.toFixed(4), 8, \" \")} ${pad(\n RAAN.toFixed(4),\n 8,\n \" \"\n )} ${E0.toFixed(7).slice(2)} ${pad(W0.toFixed(4), 8, \" \")} ${pad(\n M0.toFixed(4),\n 8,\n \" \"\n )} ${pad(N0.toFixed(8), 11, \" \")}000000`;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":4540,"value":"{\n const terms = {\n // LEO: altitude < 1000,\n // MEO: altitude > 5000 && altitude < 20000,\n // GEO: Math.abs(altitude - 35785) < 100,\n // Geostationary: Math.abs(altitude - 35785) < 100 && I0 % 170 < 10,\n Equatorial: I0 % 170 < 10,\n Polar: Math.abs(I0 - 90) < 10,\n Eccentric: E0 > 1e-2,\n Orbit: 1\n };\n\n return md`Orbital Descriptors: \n**${Object.keys(terms)\n .filter((k) => terms[k])\n .join(\"**, **\")}**`;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":82,"value":"container = html`

`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":656,"value":"playback = {\n reset;\n const step = 30; //ms per frame\n let unix = +T0;\n while (1) {\n yield new Date((unix += step * viewof speed.value));\n Promises.delay(step);\n }\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":4225,"value":"viewof speed = Inputs.range([0, 5e4], {\n label: \"Speed\",\n value: 1e4,\n format: (n) => n.toFixed(1),\n transform: (v) => Math.log(v + 1)\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":1228,"value":"viewof reset = Inputs.button(\"Reset\")","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":3638,"value":"md`### Data\nPropagation Model: [satellite.js](https://github.com/shashwatak/satellite-js)`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":5177,"value":"distanceFromCenterKm = Math.sqrt(\n propagation[0] ** 2 + propagation[1] ** 2 + propagation[2] ** 2\n) / 1000","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":3175,"value":"satellite = satellitejs.twoline2satrec(...tle.split(\"\\n\"))","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":3296,"value":"$31","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":5051,"value":"mutable iteration=0;","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":4829,"value":"coverage = {\n return;\n // const len = 99;\n // const wrap = mutable trail.length\n // ? Math.floor((mutable trail[trail.length - 1][0] + 180) / 360)\n // : 0;\n // if (Math.abs(wrap) > 0) {\n // let excess = mutable trail.reduce(\n // (a, b) => (Math.abs(a) > Math.abs(b[0] / 360) ? b[0] / 360 : a),\n // 100\n // );\n // excess = excess < 0 ? Math.ceil(excess) : Math.floor(excess);\n // for (let i = 1; i < mutable trail.length; i++) {\n // mutable trail[i][0] -= 360 * excess;\n // }\n // }\n // const diff = mutable trail.length\n // ? Math.round((mutable trail[trail.length - 1][0] - propagation[0][0]) / 360)\n // : 0;\n // mutable trail = mutable trail.slice(\n // trail.length > len ? trail.length - len : 0\n // );\n // mutable trail.push([\n // propagation[0][0] + (wrap + diff * 360),\n // propagation[0][1]\n // ]);\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":4210,"value":"mutable trail = {\n T0;\n I0;\n RAAN;\n E0;\n W0;\n M0;\n N0;\n N1;\n reset;\n return [];\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":5115,"value":"venusAngle = ((360 * +playback) / 1000 / 60 / 60 / 24 / 224.701) % 360","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":2881,"value":"md`### Rendering`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":3432,"value":"$32","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":179,"value":"deckgl = new deck.DeckGL({\n container,\n views: new EarthView({\n resolution: 10\n }),\n initialViewState: {\n longitude: -100,\n latitude: 50,\n zoom: 0,\n minZoom: -5,\n maxZoom: 5\n },\n parameters: {\n cull: false\n },\n controller: { inertia: true, scrollZoom: { speed: 0.1 } }\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":5094,"value":"class EarthView extends deck._GlobeView {\n // This view modifies globe view to be more appropriate for visualizing orbits around the earth:\n // - Zoom to/from the earth's center rather than the current mouse position.\n // - Rotate the earth smoothly regardless of what part of earth or space is dragged.\n\n static displayName = \"EarthView\";\n\n get ViewportType() {\n return EarthViewport;\n }\n\n get ControllerType() {\n return EarthController;\n }\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":5090,"value":"$33","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":5081,"value":"class EarthViewport extends deck._GlobeViewport {\n // Rotate the earth smoothly regardless of what part of earth or space is dragged.\n\n unproject(xyz, { topLeft = true, targetZ } = {}) {\n const gain = Math.min(Math.pow(2, -this.zoom) / 4, 0.5);\n return [this.longitude + xyz[0] * gain, this.latitude - xyz[1] * gain];\n }\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":2888,"value":"md`### Libraries`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":4455,"value":"getQueryParam = (name) => new URL(location.href).searchParams.get(name)\n// from https://observablehq.com/@maddievision/get-query-params","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":3262,"value":"satellitejs = import(\n \"https://unpkg.com/satellite.js@4.1.3/dist/satellite.es.js?module\"\n)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":1730,"value":"deck = require.alias({\n h3: {},\n s2Geometry: {},\n luma: {}\n})(\"deck.gl@~8.9.14/dist.min.js\")","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":3726,"value":"html``","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":658,"value":"import { Scrubber } from \"@mbostock/scrubber\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"}],"files":"$W34","stdlib":"1","titling":"auto"}} 30:"$2f:body"