Two zodiac traditions on one poster
The Western zodiac is a tropical system: signs are defined by the sun’s position along the ecliptic, not by constellations in the sky, so each sign keeps a fixed calendar window regardless of year. The embedded boundary table uses the standard dates — Aries from March 21, Taurus from April 20, Gemini from May 21, Cancer from June 22, Leo from July 23, Virgo from August 23, Libra from September 23, Scorpio from October 24, Sagittarius from November 23, Capricorn from December 22, Aquarius from January 20 and Pisces from February 19. A birth on the last day of a cusp is assigned to the sign whose window contains it, and each sign is printed with its classical element (fire, earth, air or water) and three short trait keywords in both languages.
The Chinese zodiac cannot be read from the Gregorian year directly, because the animal changes at the lunar new year. To handle this correctly the tool contains a built-in table of the actual Spring Festival dates from 1960 through 2050, rather than a flat January 1 cut-off. A baby born on February 8 2016 belongs to the Monkey because that date comes before February 8’s new year? In fact the 2016 new year fell on February 8, so a birth on February 8 already belongs to the Monkey; February 7 still belongs to the Goat. The poster checks each January or February birth against the exact boundary day, steps back one animal when needed, and then walks the twelve-animal cycle of rat, ox, tiger, rabbit, dragon, snake, horse, goat, monkey, rooster, dog and pig. Dates outside the table use the traditional Lichun approximation of February 4, which the on-page note states clearly.
Composing and exporting the pair
Both birthdays render into two stacked panels, each with a name, the formatted date, a Western medallion, the element and bilingual keywords, and a Chinese-zodiac medallion with the animal character, its year and traits. Whether you are pairing siblings, parents with a newborn, or twins born across a lunar boundary, the layout updates instantly in the 1200-pixel preview and is repainted from scratch at 300 dots per inch on download, from A4 to 24×36 inches, finished with a discreet Memory Poster Studio footer mark. All dates stay in your browser, with no account and no watermark.
两种生肖传统，合成一张海报
西方星座属于回归黄道体系：星座由太阳沿黄道运行的位置决定，与天空中的真实星座位置无关，因此每个星座的公历日期区间在任何年份都固定不变。工具内置标准交界表：白羊座 3 月 21 日起、金牛座 4 月 20 日起、双子座 5 月 21 日起、巨蟹座 6 月 22 日起、狮子座 7 月 23 日起、处女座 8 月 23 日起、天秤座 9 月 23 日起、天蝎座 10 月 24 日起、射手座 11 月 23 日起、摩羯座 12 月 22 日起、水瓶座 1 月 20 日起、双鱼座 2 月 19 日起。交界日当天出生归入包含该日的星座，每个星座还会标出其古典元素（火、土、风、水）与三个简短特质关键词，中英双语并列。
中国生肖不能直接按公历年判断，因为属相在农历新年才交接。为正确处理，工具内置了 1960 至 2050 年真实春节日期表，而不是简单地按 1 月 1 日分界：2016 年的春节是 2 月 8 日，这一天出生的孩子已属猴，而 2 月 7 日出生仍属羊；海报会把一、二月的出生日期与当年春节当天逐日比较，必要时回退一个属相，再沿鼠、牛、虎、兔、龙、蛇、马、羊、猴、鸡、狗、猪十二循环定位。春节表覆盖年份之外，按通行的立春 2 月 4 日近似分界，并在页面提示中明确注明这一近似规则。
组合与导出双人海报
两个出生日期会分别渲染为上下两块面板：每块包含姓名、格式化日期、西方星座圆章、元素与双语关键词，以及中国生肖圆章（含生肖汉字、所属年份与特质）。无论是兄弟姐妹、父母与新生儿，还是恰好处在农历年界两侧的双胞胎，版式都会在 1200 像素预览中即时更新；下载时再按 A4 至 24×36 英寸以每英寸 300 点从零重绘，并以低调的 Memory Poster Studio 页脚小字收尾。所有日期只留在你的浏览器里，无需账号，也没有水印。
Why can the Chinese animal differ from the year of birth?
Because the animal changes at the lunar Spring Festival, which falls somewhere between January 21 and February 21. For January and February dates the tool compares the day with the exact new-year date in the built-in 1960–2050 table and steps back one animal if the birth precedes it. Only outside those years does it fall back to the February 4 Lichun estimate.
为什么属相可能和出生公历年不一致？
因为属相在农历春节才交接，而春节落在 1 月 21 日至 2 月 21 日之间。一、二月的出生日期会与内置 1960–2050 春节表中的具体日期比较，出生在春节之前则回退到上一个属相；只有超出该年份范围时，才采用 2 月 4 日立春的近似分界。
Are the Western sign dates astronomically correct?
They use the standard tropical zodiac boundaries used by Western astrology, which is the system the sign names belong to. The astronomical constellation boundaries differ slightly because of precession, but pop-culture and natal astrology both use these conventional dates.
西方星座的日期在天文学上准确吗？
这里采用西方占星通用的回归黄道日期，这也是星座名称所属的体系。由于岁差，天文星座的真实边界会有细微偏差，但日常所说的星座与本命占星都使用这套约定日期。
Can the poster be made for twins or a couple with one sign unknown?
Yes. Each panel is independent: leave a date blank and that panel simply shows a placeholder, so you can complete the second half later. Twins minutes apart share both signs unless the birth crosses midnight into a new cusp day or the lunar new-year boundary.
双胞胎或情侣其中一方信息不全也能做吗？
可以。两块面板相互独立，日期留空时该块显示占位，之后补齐即可。双胞胎相隔几分钟通常星座属相都相同，除非出生恰好跨过午夜交界日或农历春节分界。
