Note: The listed coordinates are BOGUS and USELESS.
10/10/2010 is the day that geocache official site celebrating 10-10-10, ten years of geocaching and ten years of Groundspeak in 2010. Also it's a birthday of Republic of China. We have a firework festival at this night.
Not just the fireworks, by standing at grand zero, you could clearly see the star Vega along with Altair and Deneb lined as Summer Triangle. It's the second brightest star in the northern celestial hemisphere, and a relatively close star at only 25 light-years from Earth.
The owner of this cache won't tell you the coords of cache. But instead, he stood on the GZ. And at the precise time, 10/10/2010, 10:10:10 p.m., he measured and recorded the Horizontal coordinate of Vega as Az/Alt: 302° 26'36"/27° 31'08", hour angle (HA) as 4h55m11.21s and right ascension (RA) as 18h37m16.10s. He asked geocachers to calculate the coords by themselves. And during measurement error of his skill and rounding error of calculation, he gave the last digits of coords and told that coords would looks like N25° 00.m90'/E121° 30.n01, where you need to calculate m,n your self and check it at Geochecker.com.
Hint: Thanks to hunter, admuk, there should be no ambiguity by using the following formula to find the day since J2000.0.
dwhole = 367 * year - trunc(7 * (year+trunc((month+9)/12))/4) + trunc(275 * month / 9) + day - 730531.5
dfrac = (hour + minute/60 + second/3600)/24
J2000 day = dwhole + dfrac
where...
hour, minute, second is the UT time
trunc() is a truncation function which gets the integer part of a number. For example: trunc(3.1412) = 3
Referenced from: http://www2.arnes.si/~gljsentvid10/sidereal.htm
Please use LMST in the referenced to calculate longitude.
三十國慶觀星寶
觀星，這也是獵人基本技
請注意：寶頁的座標是假的、無效的。
2010 年 10 月 10 日，地理藏寶的官方網站慶祝 10-10-10 Geocaching 十周年。這天，也是中華民國的生日。我們晚上，有國慶煙火來慶祝這特別的一天。
不只是煙火，站在寶點，你也可以清楚的看到中國著名的織女星。織女、牽牛、與天津四這三顆夏日明星，合組著名的夏日大三角，清清楚楚的佔據在夏日的夜空上，很容易就可以認出他們來。織女星也是北半球星空裡第二明亮的恆星，非常的靠近太陽系，僅僅 25 光年而已。
這個寶的寶主他很壞，他不明講這個寶的 GPS 座標。不過呢，他站在寶點上，在 "西元 2010 年十月十日，晚上十點十分十秒" 準點，他測量並且記錄了織女星在地平座標系的座標，在方位角與仰角 (Az/Alt) 為 "302° 26'36"/27° 31'08"，又測量了時角 (HA) 為 4h55m11.21s，赤經 (RA)為 18h37m16.10s。他要求獵友們自己計算座標。不過由於技術欠佳，在測量上有誤差外，計算上也因有捨入誤差，他給了 GPS 座標最後的幾個數字。他說座標大概如下：N25° 00.m90'/E121° 30.n01。 數字 m,n 就留個各位獵友自己來計算。你也可以來這裡檢查 Geochecker.com。
提示: 謝謝獵友 admuk 熱情提供，請用下面的公式來計算 J2000 應該就不會有混淆的情況發生。
dwhole = 367 * year - trunc(7 * (year+trunc((month+9)/12))/4) + trunc(275 * month / 9) + day - 730531.5
dfrac = (hour + minute/60 + second/3600)/24
J2000 day = dwhole + dfrac
其中...
hour, minute, second 是世界時
trunc() 是一個函式，會拿掉小數，留下整數。比如說：trunc(3.1412) = 3
上面的公式參考： http://www2.arnes.si/~gljsentvid10/sidereal.htm。
你可以使用其中 LMST 計算的方法來求得寶點的經度。