(function() { try { var root = typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : Function("return this")(); var doc = root.document; var html = doc && doc.documentElement; if (html) { var supportsModernCss = !!( root.CSS && root.CSS.supports && root.CSS.supports("display", "grid") && root.CSS.supports("aspect-ratio", "1 / 1") ); if (!supportsModernCss) { var htmlClass = html.className || ""; if ((" " + htmlClass + " ").indexOf(" legacy-browser ") === -1) { html.className = (htmlClass ? htmlClass + " " : "") + "legacy-browser"; } html.setAttribute("data-legacy-browser", "true"); } } if (typeof root.globalThis === "undefined") { try { Object.defineProperty(root, "globalThis", { value: root, configurable: true, writable: true }); } catch (e) { root.globalThis = root; } } if (typeof root.CustomEvent !== "function") { var CustomEventPolyfill = function(event, params) { var customEventParams = params || { bubbles: false, cancelable: false, detail: null }; var customEvent = document.createEvent("CustomEvent"); customEvent.initCustomEvent( event, !!customEventParams.bubbles, !!customEventParams.cancelable, customEventParams.detail ); return customEvent; }; CustomEventPolyfill.prototype = root.Event && root.Event.prototype; root.CustomEvent = CustomEventPolyfill; } if (root.Node && root.Node.prototype && typeof root.Node.prototype.getRootNode !== "function") { root.Node.prototype.getRootNode = function() { var node = this; while (node.parentNode) { node = node.parentNode; } return node; }; } if (root.NodeList && root.NodeList.prototype && typeof root.NodeList.prototype.forEach !== "function") { root.NodeList.prototype.forEach = Array.prototype.forEach; } if (typeof root.ResizeObserver === "undefined") { root.ResizeObserver = function() {}; root.ResizeObserver.prototype.observe = function() {}; root.ResizeObserver.prototype.unobserve = function() {}; root.ResizeObserver.prototype.disconnect = function() {}; } if (root.Intl && typeof root.Intl.Locale !== "function") { root.Intl.Locale = function Locale(tag) { var value = String(tag || "en"); var parts = value.replace(/_/g, "-").split("-"); this.baseName = value; this.language = parts[0] || "en"; this.region = parts.length > 1 ? parts[parts.length - 1].toUpperCase() : undefined; }; root.Intl.Locale.prototype.toString = function() { return this.baseName; }; } if (!Object.assign) { Object.assign = function(target) { if (target == null) { throw new TypeError("Cannot convert undefined or null to object"); } var output = Object(target); for (var i = 1; i < arguments.length; i += 1) { var source = arguments[i]; if (source == null) { continue; } for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { output[key] = source[key]; } } } return output; }; } if (!Object.values) { Object.values = function(source) { return Object.keys(source).map(function(key) { return source[key]; }); }; } if (!Object.entries) { Object.entries = function(source) { return Object.keys(source).map(function(key) { return [key, source[key]]; }); }; } if (!Object.fromEntries) { Object.fromEntries = function(entries) { if (entries == null) { throw new TypeError("Object.fromEntries() requires a single iterable argument"); } var object = {}; var iteratorKey = typeof Symbol !== "undefined" && Symbol.iterator; if (iteratorKey && entries[iteratorKey]) { var iterator = entries[iteratorKey](); var step = iterator.next(); while (!step.done) { object[step.value[0]] = step.value[1]; step = iterator.next(); } return object; } for (var i = 0; i < entries.length; i += 1) { object[entries[i][0]] = entries[i][1]; } return object; }; } if (!Object.hasOwn) { Object.hasOwn = function(object, property) { if (object == null) { throw new TypeError("Cannot convert undefined or null to object"); } return Object.prototype.hasOwnProperty.call(Object(object), property); }; } if (!Array.from) { Array.from = function(source, mapFn, thisArg) { if (source == null) { throw new TypeError("Array.from requires an array-like object"); } var output = []; var iteratorKey = typeof Symbol !== "undefined" && Symbol.iterator; var i = 0; var value; if (iteratorKey && source[iteratorKey]) { var iterator = source[iteratorKey](); var step = iterator.next(); while (!step.done) { value = step.value; output.push(mapFn ? mapFn.call(thisArg, value, i) : value); i += 1; step = iterator.next(); } return output; } var length = source.length >>> 0; for (i = 0; i < length; i += 1) { value = source[i]; output.push(mapFn ? mapFn.call(thisArg, value, i) : value); } return output; }; } if (!Array.prototype.includes) { Array.prototype.includes = function(searchElement, fromIndex) { var length = this.length >>> 0; if (length === 0) return false; var index = fromIndex | 0; var start = Math.max(index >= 0 ? index : length - Math.abs(index), 0); while (start < length) { if (this[start] === searchElement || (this[start] !== this[start] && searchElement !== searchElement)) { return true; } start += 1; } return false; }; } if (!Array.prototype.at) { Object.defineProperty(Array.prototype, "at", { configurable: true, writable: true, value: function(index) { var object = Object(this); var length = object.length >>> 0; var relativeIndex = Number(index) || 0; if (relativeIndex < 0) { relativeIndex += length; } if (relativeIndex < 0 || relativeIndex >= length) { return undefined; } return object[relativeIndex]; } }); } if (!Array.prototype.flat) { Array.prototype.flat = function(depth) { var flattenDepth = depth === undefined ? 1 : Number(depth) || 0; var result = []; var flatten = function(items, currentDepth) { for (var i = 0; i < items.length; i += 1) { if (Array.isArray(items[i]) && currentDepth > 0) { flatten(items[i], currentDepth - 1); } else { result.push(items[i]); } } }; flatten(this, flattenDepth); return result; }; } if (!Array.prototype.flatMap) { Array.prototype.flatMap = function(callback, thisArg) { return Array.prototype.map.call(this, callback, thisArg).flat(); }; } if (!String.prototype.trimStart) { String.prototype.trimStart = String.prototype.trimLeft || function() { return String(this).replace(/^\s+/, ""); }; } if (!String.prototype.trimEnd) { String.prototype.trimEnd = String.prototype.trimRight || function() { return String(this).replace(/\s+$/, ""); }; } if (!String.prototype.at) { Object.defineProperty(String.prototype, "at", { configurable: true, writable: true, value: function(index) { var string = String(this); var length = string.length >>> 0; var relativeIndex = Number(index) || 0; if (relativeIndex < 0) { relativeIndex += length; } if (relativeIndex < 0 || relativeIndex >= length) { return undefined; } return string.charAt(relativeIndex); } }); } if (!String.prototype.replaceAll) { String.prototype.replaceAll = function(searchValue, replaceValue) { var string = String(this); var isRegExp = Object.prototype.toString.call(searchValue) === "[object RegExp]"; if (isRegExp) { if (!searchValue.global) { throw new TypeError("String.prototype.replaceAll called with a non-global RegExp argument"); } return string.replace(searchValue, replaceValue); } var search = String(searchValue); var replacementIsFunction = typeof replaceValue === "function"; var result = ""; var position = 0; var index; var replacement; if (search === "") { replacement = replacementIsFunction ? replaceValue("", 0, string) : String(replaceValue); result = replacement; for (index = 0; index < string.length; index += 1) { result += string.charAt(index) + replacement; } return result; } index = string.indexOf(search, position); while (index !== -1) { replacement = replacementIsFunction ? replaceValue(search, index, string) : String(replaceValue); result += string.slice(position, index) + replacement; position = index + search.length; index = string.indexOf(search, position); } return result + string.slice(position); }; } if (root.Promise && !root.Promise.prototype.finally) { root.Promise.prototype.finally = function(callback) { var PromiseCtor = this.constructor; return this.then( function(value) { return PromiseCtor.resolve(callback()).then(function() { return value; }); }, function(reason) { return PromiseCtor.resolve(callback()).then(function() { throw reason; }); } ); }; } if (root.Promise && !root.Promise.allSettled) { root.Promise.allSettled = function(values) { var items = Array.from(values); return root.Promise.all(items.map(function(value) { return root.Promise.resolve(value).then( function(resolvedValue) { return { status: "fulfilled", value: resolvedValue }; }, function(reason) { return { status: "rejected", reason: reason }; } ); })); }; } if (typeof root.queueMicrotask !== "function") { root.queueMicrotask = function(callback) { if (root.Promise) { root.Promise.resolve().then(callback).catch(function(error) { root.setTimeout(function() { throw error; }, 0); }); return; } root.setTimeout(callback, 0); }; } if ( root.Blob && root.Blob.prototype && root.FileReader && root.Promise && typeof root.Blob.prototype.arrayBuffer !== "function" ) { root.Blob.prototype.arrayBuffer = function() { var blob = this; return new root.Promise(function(resolve, reject) { var reader = new root.FileReader(); reader.onload = function() { resolve(reader.result); }; reader.onerror = function() { reject(reader.error || new Error("Blob could not be read")); }; reader.onabort = function() { reject(new Error("Blob read was aborted")); }; reader.readAsArrayBuffer(blob); }); }; } if ( root.HTMLCanvasElement && root.HTMLCanvasElement.prototype && root.Blob && root.atob && typeof root.HTMLCanvasElement.prototype.toBlob !== "function" ) { root.HTMLCanvasElement.prototype.toBlob = function(callback, type, quality) { var dataUrl; try { if (typeof this.toDataURL !== "function") { root.setTimeout(function() { callback(null); }, 0); return; } dataUrl = this.toDataURL(type, quality); } catch (e) { root.setTimeout(function() { callback(null); }, 0); return; } var separatorIndex = dataUrl.indexOf(","); var metadata = separatorIndex >= 0 ? dataUrl.slice(5, separatorIndex) : ""; var payload = separatorIndex >= 0 ? dataUrl.slice(separatorIndex + 1) : ""; var mimeMatch = /^([^;]+)/.exec(metadata); var mimeType = mimeMatch ? mimeMatch[1] : "image/png"; var blob = null; try { if (metadata.toLowerCase().indexOf(";base64") >= 0) { var binary = root.atob(payload); var bytes = new Uint8Array(binary.length); for (var index = 0; index < binary.length; index += 1) { bytes[index] = binary.charCodeAt(index); } blob = new root.Blob([bytes], { type: mimeType }); } else { blob = new root.Blob([decodeURIComponent(payload)], { type: mimeType }); } } catch (e) { blob = null; } root.setTimeout(function() { callback(blob); }, 0); }; } if (root.URL && typeof root.URL.canParse !== "function") { root.URL.canParse = function(url, base) { try { if (base === undefined) { new root.URL(url); } else { new root.URL(url, base); } return true; } catch (e) { return false; } }; } if (typeof root.requestIdleCallback !== "function") { root.requestIdleCallback = function(callback) { var start = Date.now(); return root.setTimeout(function() { callback({ didTimeout: false, timeRemaining: function() { return Math.max(0, 50 - (Date.now() - start)); } }); }, 1); }; } if (typeof root.cancelIdleCallback !== "function") { root.cancelIdleCallback = function(id) { root.clearTimeout(id); }; } if (typeof root.AbortController === "undefined") { var AbortSignalPolyfill = function() { this.aborted = false; this.onabort = null; }; AbortSignalPolyfill.prototype.addEventListener = function(type, listener) { if (type === "abort") { this.onabort = listener; } }; AbortSignalPolyfill.prototype.removeEventListener = function(type, listener) { if (type === "abort" && this.onabort === listener) { this.onabort = null; } }; AbortSignalPolyfill.prototype.dispatchEvent = function(event) { if (event && event.type === "abort" && typeof this.onabort === "function") { this.onabort.call(this, event); } return true; }; root.AbortController = function AbortController() { this.signal = new AbortSignalPolyfill(); }; root.AbortController.prototype.abort = function() { if (this.signal.aborted) { return; } this.signal.aborted = true; this.signal.dispatchEvent({ type: "abort" }); }; } } catch (e) {} })();

NGC 6811 Hole in a Cluster

Eagle Nebula

Crescent Nebula