-
1
-
2
-
3
Real astronomy, not random dots
Every night-sky poster on Memory Poster Studio is produced by real astronomical computation rather than a decorative scatter of random dots. Your date is converted to a Julian Day and combined with the standard Meeus sidereal-time formulas to find exactly how the celestial sphere was rotated above your chosen city. Star positions come from the measured ATHYG catalog, and each star is transformed into local altitude and azimuth, so stars below the horizon are hidden just as they were in reality. Moon phases, sunrise and golden-hour times use the same family of published algorithms. At poster scale the result is far more accurate than the eye can check — the map you print genuinely is the sky of that night.
Private by design: zero uploads
Nothing you enter ever leaves your device. There is no account and no sign-up form, and no server ever receives the names, dates, birth measurements or coordinates that make a poster personal. The photo-based tools read images locally through the browser's own canvas processing, which means your pictures are never uploaded, stored on our side, or shared with a third party. Everything keeps working offline once the page has loaded; clearing your browser data removes every trace.
What 300 DPI actually means
DPI measures dots per inch at the print shop, and 300 DPI is the professional threshold at which a poster looks crisp from normal viewing distance. The on-screen preview is only a lightweight rendering, but every download is repainted from scratch at 300 dots per inch in your exact chosen size. A 24 × 36 inch poster therefore exports at roughly 7200 × 10800 pixels. Because text, lines and stars are vector data, they are re-rasterized at that resolution instead of being enlarged from a small screenshot, so typography stays sharp and the blacks stay deep.
Free today, and free of watermarks
We believe a keepsake should not carry someone else's logo. Every poster downloads without a watermark, with no trial period, no daily quota and no hidden paywall — a Pro license for batch and commercial features may come later, but everything on the page today is free forever. There are no surprise fees before the download button and no files sent by email; what you make is yours to print at home or through any print shop.
Built for the moments worth framing
The collection is organized around gifting moments: the night you first met, a wedding sky, a baby's birth stats, a first Christmas or Mother's Day, a long-distance love map, the route of an unforgettable trip, vows and song lyrics set in typography, or a gallery wall of family milestones. Pair a star map with a coordinate print, add a quote, check your DPI before ordering, and walk away with a gallery-ready gift in minutes — no designer, no appointment, and no waiting on a stranger's inbox.
真实天文，而非随机撒点
Memory Poster Studio 的每一张夜空海报都来自真实的天文计算，而不是装饰性的随机星点。你选择的日期会被换算为儒略日，再用标准的 Meeus 恒星时公式求出此刻天球相对你所选城市转过的角度。恒星位置来自实测的 ATHYG 星表，每颗星都会被换算为当地的高度角与方位角，地平线以下的星会被如实隐藏；月相、日出与黄金时刻也使用同一套公开的天文算法。在海报尺寸下，计算精度远超肉眼可辨——你打印出来的，确实是那一夜的星空。
隐私优先：零上传
你输入的任何内容都不会离开自己的设备。网站没有账号、没有注册表单，也没有任何服务器会收到让海报变得私密的名字、日期、出生数据或坐标。需要照片的工具只通过浏览器自身的画布能力在本地处理图片，照片永远不会被上传、存储在我们这里，或转交第三方。页面一旦加载完成，断网也能使用；清除浏览器数据即可抹去全部痕迹。
300 DPI 到底是什么
DPI 衡量印刷时每英寸的墨点数，300 DPI 是海报在正常观看距离下保持清晰的专业门槛。屏幕上的预览只是轻量渲染，而每次下载都会按你选定的尺寸以每英寸 300 点从零重绘：一张 24 × 36 英寸的海报约导出 7200 × 10800 像素。由于文字、线条与星点都是矢量数据，它们会在该分辨率下重新栅格化，而不是从小截图硬拉大，因此排版锐利、黑色深沉。
今日免费，也无水印
我们相信纪念品不该带着别人的 logo。每张海报下载都没有水印，没有试用期、没有每日次数限制，也没有隐藏付费墙——未来可能推出面向批量与商业功能的 Pro 授权，但今天页面上的一切永久免费。下载前不会有意外收费，也不需要等待邮件；成品属于你，可以在家或任意打印店输出。
为值得装框的时刻而生
整站工具围绕送礼时刻组织：初次相遇的夜晚、婚礼星空、宝宝出生数据、第一个圣诞节或母亲节、异地恋爱情地图、难忘旅程的路线、排成字体的誓言与歌词，或是一面挂满家庭里程碑的画廊墙。把星空地图与坐标海报配对、加上引言、下单前检查 DPI，几分钟内就能得到画廊级礼物——不必请设计师、不必预约，也不必等待别人的收件箱。
Are the night-sky posters scientifically accurate?
Yes. Star positions come from the measured ATHYG catalog and the sky rotation uses the Meeus sidereal-time formulas, including local longitude. Stars below the horizon are clipped, so the chart shows only what was actually overhead. For modern dates the error is a small fraction of a degree — far finer than anything visible at poster size.
夜空海报在科学上准确吗？
准确。恒星位置来自实测的 ATHYG 星表，天空旋转采用 Meeus 恒星时公式并计入当地经度；地平线以下的星会被裁掉，图上只呈现当时真正位于天空中的部分。现代日期的计算误差远小于一度的零头，远超海报尺寸下任何可见的精度要求。
Do I need to sign up or upload my photos?
No. There is no account, no password and no email step. All text, dates and coordinates stay in your browser, and the photo tools process images locally through canvas, so pictures for collages or resizing are never uploaded. The pages even work offline after the first load.
需要注册或上传照片吗？
都不需要。网站没有账号、没有密码，也不经过邮件步骤。所有文字、日期与坐标都只留在你的浏览器里；照片类工具通过画布在本地处理图片，拼贴或缩放所用的照片永远不会被上传。页面首次加载后，断网也能使用。
What is 300 DPI, and which file do I receive?
You receive a PNG repainted at 300 dots per inch in your chosen size — A4, A3, 16×20, 18×24, 24×36 inches or a 12-inch square. At 24×36 that is about 7200×10800 pixels, suitable for framing and gallery walls. Print it on genuine photo or matte poster paper for the deepest blacks.
300 DPI 是什么？我会拿到什么文件？
你会得到一张按所选尺寸以每英寸 300 点重绘的 PNG——支持 A4、A3、16×20、18×24、24×36 英寸与 12 英寸方形。24×36 尺寸约为 7200×10800 像素，适合装框与画廊墙展示。建议使用真正的相纸或哑光海报纸，黑色会更加深沉。
Why is it free with no watermark, and will that change?
A keepsake should not advertise someone else's brand, so exports carry no watermark, no quota and no trial lock. Today every tool is free forever. A future Pro license may add batch and commercial features, but the free tools shown here will remain free and watermark-free.
为什么免费且没有水印？以后会变吗？
纪念品不该替别人的品牌做广告，因此导出文件没有水印、没有次数限制、没有试用期锁定。今天的每个工具都永久免费。未来的 Pro 授权可能增加批量与商业功能，但这里提供的免费工具会继续免费、继续无水印。