互動可見度圖Visibility Plot
設定日期與目標後，點「生成可見度圖」Set date & targets, then click “Generate Plot”
座標格式說明Coordinate Formats
RA（赤經）與 Dec（赤緯）皆接受下列任一格式：RA and Dec each accept any of these:
| 格式Format | RA | Dec |
|---|---|---|
| 冒號分隔Colon | 20:58:47 | +44:19:48 |
| 空格分隔Spaces | 20 58 47 | -29 00 51 |
| 單位符號Units | 20h58m47s | 44°19'48" |
| 十進位度Decimal deg | 314.70 | 44.33 |
• RA 用冒號/空格時視為「時:分:秒」（0–24h）；純數字視為「度」（0–360）。
• Dec 一律為「度:分:秒」或十進位度，可加正負號。
• 也可在上方搜尋框輸入天體名稱，透過 CDS SIMBAD 自動填入座標。
• RA in colon/space form is hours:min:sec (0–24h); a bare number is degrees (0–360).
• Dec is deg:min:sec or decimal degrees, sign optional.
• Or type an object name above to auto-fill via CDS SIMBAD.
圖表說明About the plot
橫軸為時間（下 UTC、上當地時間），縱軸為高度角（右側對應大氣質量 Airmass）。背景深淺代表暮光階段，最深為天文夜。每個目標有專屬顏色與編號，曲線上每隔約 3 小時標一次編號，方便黑白列印辨識。虛線 30° 為常用觀測門檻。 X-axis is time (UTC below, local above); Y-axis is altitude (right side shows airmass). Background shading marks twilight stages, darkest = astronomical night. Each target has its own colour and number; the number is repeated along the curve every ~3 h so it stays readable in black & white. The dotted 30° line is a common observing threshold.