From a birthday to a tropical zodiac sign
Entering only a month and a day is enough, because tropical astrology — the system used by almost all newspapers and birth charts — is defined by the seasons rather than by the physical constellations. The tool compares the date against the standard boundaries in the embedded zodiac table, from Aries opening at the March equinox window on March 21 through Pisces closing on March 20, and returns one of the twelve signs in an instant. Leap years need no special handling because February 29 simply falls within the Pisces range. The boundaries displayed on the poster are those same tropical dates, not the uneven sidereal boundaries used by Vedic astrology, so your result matches the sign on virtually every Western birth chart.
Drawing the real constellation behind the sign
Here the poster goes beyond a zodiac symbol: it maps the sign to its astronomical constellation and draws the actual figure. All twelve sign keys — Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, Sagittarius, Capricornus, Aquarius and Pisces — exist in the embedded catalog of traditional stick figures, and every segment joins real J2000 star coordinates from the ATHYG v3.2 database rather than decorative spline points. The figure is laid out directly in equatorial coordinates, so the shape is astronomically upright: right ascension runs horizontally, declination vertically, and the brightest catalog stars in and around the figure are sized by their measured visual magnitude. A surrounding field of faint catalog stars fills the genuine neighborhood of your constellation instead of random wallpaper dots.
Three layouts are offered: Sky frames the figure inside a circular stereographic-style vignette with a gold ring and compass points, Portrait fills the whole sheet edge to edge with the constellation centered like a gallery print, and Minimal isolates the line art on a calm field with generous whitespace. Every poster prints the constellation name, its tropical date range, one of the four classical elements — Fire, Earth, Air or Water — and four bilingual signature traits. At 300 DPI the stars, lines and serif typography are all repainted as vectors, giving a sharp free keepsake that runs entirely offline with no watermark.
从生日到回归黄道星座
只需输入月份与日期即可，因为几乎所有报纸星座与西方出生星盘使用的回归占星，依据的是季节而非天上星座的物理位置。工具会把日期与内置星座表的标准分界比较：从 3 月 21 日春分窗口开启的白羊座，一直到 3 月 20 日收尾的双鱼座，瞬间返回十二宫之一。闰年无需特殊处理，因为 2 月 29 日天然落在双鱼座区间内。海报上展示的日期区间也正是这些回归制分界，而不是吠陀占星使用的、并不均匀的恒星制分界，因此结果与几乎所有西方出生星盘上的星座一致。
绘制星座背后真正的星图
在星座符号之外，这张海报更进一步：它把星座映射到天文学上同名星座，绘制真实的造型。十二个宫位——白羊、金牛、双子、巨蟹、狮子、室女、天秤、天蝎、人马、摩羯、宝瓶与双鱼——在内置的传统连线造型表中全部存在，每条线段连接的都是 ATHYG v3.2 数据库中真实的 J2000 恒星坐标，而非装饰性的样条点。图形直接以赤道坐标排版，因此造型在天文学上方向端正：赤经横向展开、赤纬纵向排列，造型内外最亮的星表恒星按实测视星等决定大小；周围一片黯淡的星表恒星则填满星座真实的天区邻居，而不是随机的墙纸式星点。
三种版式可选：星空式把造型收入圆形立体投影风格的暗角圆盘，配金色圆环与方位标；竖版海报让图形居中、底色铺满整页出血，宛如画廊印品；极简式则把连线独立放在安静的底色上，留出大量呼吸空间。每张海报都会印出星座名、回归制日期区间、四元素之一——火、土、风、水——以及四个双语特质关键词。以 300 DPI 导出时，星点、连线与衬线字体全部作为矢量重绘，成品锐利、免费、可离线完成且没有水印。
My birthday is on a cusp day — which sign do I get?
The standard tropical boundary is used, at the exact calendar day: for example March 21 is Aries and March 20 is Pisces, with no hour calculation. If you are a cusp baby, the poster will state the precise date range printed beneath the constellation so the boundary is always transparent.
我的生日在交界日，会算成哪个星座？
工具采用标准回归制分界，精确到日历日：例如 3 月 21 日为白羊座、3 月 20 日为双鱼座，不做具体时辰推算。若你恰好出生在交界日，海报上星座下方会印出完整的日期区间，分界一目了然。
Why does the drawn constellation look different from my zodiac symbol?
The symbols (the ram, the bull, the twins and so on) are ancient pictograms, while the poster draws the astronomical star pattern that ancient Mediterranean stargazers imagined those pictures onto. Your sign's glyph is printed as a large watermark-style mark beside the name, while the real stars and stick lines carry the scientific content.
为什么画出来的星座和星座符号不一样？
公羊、金牛、双子等符号是古老的象形图案，而海报绘制的是古代地中海观星者在这片星点上想象出图形时所依据的真实星象。你的星座字符会作为大号水印风格标记印在名称旁，真正的恒星与连线则承担科学部分。
Do I need my birth year or birthplace?
No. Tropical signs depend only on the month and day, and the constellation is plotted in fixed equatorial coordinates rather than the rotating local sky, so year, time and city are irrelevant. That makes this a fast companion to the full birthday night-sky poster when you only want the birth-sign figure.
需要出生年份或出生地吗？
不需要。回归星座只取决于月、日，而星座图形按固定赤道坐标绘制、不随地方天空旋转，因此与年份、时间、城市无关。当你只想要星座造型时，它是生日夜空海报的快捷搭档。
