Public
Edited
Sep 23, 2024
Paused
25 forks
98 stars
Star MapSolar AnalemmasExoplanetsThe Sun’s View of the EarthLunar VisibilityPhases of the Moon
Hertzsprung–Russell diagram
chart = {
// Declare the chart dimensions and margins.
const width = 928;
const height = Math.round(width * 1.2)
const marginTop = 40;
const marginRight = 40;
const marginBottom = 40;
const marginLeft = 40;
// Ceate the scales.
const x = d3.scaleLinear([-0.39, 2.19], [marginLeft, width - marginRight]);
const y = d3.scaleLinear([-7, 19], [marginTop, height - marginBottom]);
const z = bv2rgb;
// Create the SVG container.
const svg = d3.create("svg")
.attr("width", width + 28)
.attr("height", height)
.attr("viewBox", [-14, 0, width + 28, height])
.attr("style", "max-width: calc(100% + 28px); height: auto;")
.style("margin", "0 -14px")
.style("background", "#000")
.style("color", "#fff")
.style("display", "block")
.attr("fill", "currentColor")
.attr("font-family", "sans-serif")
.attr("font-size", 10);
// Create a small (sub pixel) rectangle for each star.
svg.append("g")
.selectAll("rect")
.data(data)
.join("rect")
.attr("x", d => x(d.color))
.attr("y", d => y(d.absolute_magnitude))
.attr("fill", d => z(d.color))
.attr("width", 0.75)
.attr("height", 0.75);
// Create the axes.
svg.append("g")
.attr("transform", `translate(${marginLeft},0)`)
.call(d3.axisLeft(d3.scaleLog(y.domain().map(m => Math.pow(10, 4.83 - m)), y.range())));
svg.append("g")
.attr("transform", `translate(${width - marginRight},0)`)
.call(d3.axisRight(y).ticks(null, "+"));
svg.append("g")
.attr("transform", `translate(0,${height - marginBottom})`)
.call(d3.axisBottom(x).ticks(null, "+f"));
svg.append("g")
.attr("transform", `translate(0,${marginTop})`)
.call(((temperatures) => d3.axisTop(x)
.tickValues(temperatures.map(color))
.tickFormat((_, i) => temperatures[i].toLocaleString("en")))
(d3.range(3000, 10001, 1000).concat(20000)));
svg.selectAll(".domain").remove();
svg.append("text")
.attr("dy", 12)
.attr("text-anchor", "middle")
.attr("transform", `translate(${marginLeft},${(marginTop + height - marginBottom) / 2}) rotate(-90)`)
.call(text => text.append("tspan").attr("fill-opacity", 0.8).text("← darker\xa0"))
.call(text => text.append("tspan").attr("font-weight", "bold").text("\xa0Luminosity L☉\xa0"))
.call(text => text.append("tspan").attr("fill-opacity", 0.8).text("\xa0brighter →"));
svg.append("text")
.attr("dy", -6)
.attr("text-anchor", "middle")
.attr("transform", `translate(${width - marginRight},${(marginTop + height - marginBottom) / 2}) rotate(-90)`)
.call(text => text.append("tspan").attr("fill-opacity", 0.8).text("← darker\xa0"))
.call(text => text.append("tspan").attr("font-weight", "bold").text("\xa0Absolute magnitude M\xa0"))
.call(text => text.append("tspan").attr("fill-opacity", 0.8).text("\xa0brighter →"));
svg.append("text")
.attr("x", (marginLeft + width - marginRight) / 2)
.attr("y", marginTop)
.attr("dy", 12)
.attr("text-anchor", "middle")
.call(text => text.append("tspan").attr("fill-opacity", 0.8).text("← hotter\xa0"))
.call(text => text.append("tspan").attr("font-weight", "bold").text("\xa0Temperature K\xa0"))
.call(text => text.append("tspan").attr("fill-opacity", 0.8).text("\xa0colder →"));
svg.append("text")
.attr("x", (marginLeft + width - marginRight) / 2)
.attr("y", height - marginBottom)
.attr("dy", -6)
.attr("text-anchor", "middle")
.call(text => text.append("tspan").attr("fill-opacity", 0.8).text("← blue\xa0"))
.call(text => text.append("tspan").attr("font-weight", "bold").text("\xa0Color B-V\xa0"))
.call(text => text.append("tspan").attr("fill-opacity", 0.8).text("\xa0red →"));
return svg.node();
}
data = FileAttachment("catalog.csv").csv({typed: true})
function bv2rgb(bv) {
bv = Math.max(-0.4, Math.min(2, bv));
let t;
return `#${[
bv < 0 ? (t = (bv + 0.4) / 0.4, 0.61 + (0.11 * t) + (0.1 * t * t))
: bv < 0.4 ? (t = bv / 0.4, 0.83 + (0.17 * t))
: 1,
bv < 0 ? (t = (bv + 0.4) / 0.4, 0.70 + (0.07 * t) + (0.1 * t * t))
: bv < 0.4 ? (t = bv / 0.4, 0.87 + (0.11 * t))
: bv < 1.6 ? (t = (bv - 0.4) / 1.20, 0.98 - (0.16 * t))
: (t = (bv - 1.6) / 0.4, 0.82 - (0.5 * t * t)),
bv < 0.4 ? 1
: bv < 1.5 ? (t = (bv - 0.4) / 1.1, 1 - (0.47 * t) + (0.1 * t * t))
: bv < 1.94 ? (t = (bv - 1.5) / 0.44, 0.63 - (0.6 * t * t))
: 0
].map(t => Math.round(t * 255).toString(16).padStart(2, "0")).join("")}`;
}
function temperature(color) {
return 4600 * (1 / (0.92 * color + 1.7) + 1 / (0.92 * color + 0.62));
}
function color(temperature) {
const u = 8464 / temperature;
return (u - 2.1344 + Math.hypot(0.9936, u)) / 1.6928;
}
Purpose-built for displays of data
Observable is your go-to platform for exploring data and creating expressive data visualizations. Use reactive JavaScript notebooks for prototyping and a collaborative canvas for visual data exploration and dashboard creation.
