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Royal Observatory Greenwich Cache Virtual Cache

Hidden : 08/08/2004
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Size: Size:   virtual (virtual)

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Geocache Description:

This virtual cache site is located on the grounds of the Royal Observatory Greenwich, wherein lie many wonders germane to navigation.

The Royal Observatory Greenwich

This virtual cache site is located along the Prime Meridian, on the grounds of the Royal Observatory Greenwich, wherein lie many wonders germane to navigation.

Since the Prime Meridian is over 12,000 miles long, one could place such a cache in quite a few locations. However, it is especially appropriate to site this cache here for a variety of reasons.

The Royal Observatory was founded in 1675 by Charles II specifically to solve the problem of longitude when at sea and out of sight of land.

This problem became somewhat more urgent in 1707, when a disaster at sea killed over 2,000 men, prompting calls for more reliable means of navigation. Parliament responded by establishing the Board of Longitude in 1714, and offering a £20,000 reward (equivalent to £2 million today!) to anyone who could solve the problem of accurately determining longitude at sea.

The problem was solved, but not for almost 60 years. The prize was claimed not by a mathematician, scientist or astronomer, but by a Yorkshire carpenter turned clockmaker, named John Harrison. The Observatory contains many wonderful clocks in its exhibition, including working models of four of Harrison's ground-breaking clocks. His H4 chronometer changed navigation forever, and is actually slightly smaller than my current GPSR!

As so often happens, the ability to accurately determine longitude led to a whole new problem: where does one measure it from? This was a thorny problem since most towns in the world at that time kept their own local time. The development of extensive railroad and communication systems during the 1850's and 1860's made the need for a universal standard even more imperative. This issue was finally resolved by the International Meridian Conference in 1884, during which the Greenwich Meridian was chosen to be the Prime Meridian of the World. For more fascinating information on this event (including who voted against Greenwich and who abstained), visit the Royal Observatory Greenwich website.

This virtual cache site is physically easy to visit, even in a wheelchair, but must be visited during daylight hours, since it is on the grounds of the Royal Observatory Greenwich. Fortunately, this is not difficult, since the Museum is open 7 days a week, 1000 to 1700 (until 1800 during the summer), and the last admission is 30 minutes before closing. Admission to the meridian courtyard and Flamsteed House now costs about £10 for adults. However, the meridian marker also extends outside the gates to the north, where it can be visited for free.

These coordinates should lead you to an area crowded by geomuggles, all queueing up to have their picture taken standing on the Prime Meridian in front of the meridian statuary. Feel free to join this long line or stand in the much shorter line for the northern marker outside the gates, because you'll need just such a picture of yourself to successfully log this cache. While you're waiting in line, use your GPSR unit to measure the exact latitude and longitude over the Prime Meridian.

How to Log This Virtual Cache

To successfully log this virtual cache, you must do the following 3 things:

  1. Post a picture on this site of you and your GPSR standing on the Prime Meridian in front of the statue. If you arrive after hours or if the line inside is too long or if you can't afford the entry fee, you may also use a picture taken on the line located on the north wall of the observatory, just outside the fence (example 1, example 2). If construction work limits access to this spot, a picture of you standing just outside the main ROG gate will also suffice.
  2. Post the coordinates on this site that you measure for this spot with your own GPSR unit.
  3. You may be fascinated (as I was) to note that your measured longitude directly over the Prime Meridian is not 000° 00.000'. Please read the excellent explanations for this discrepancy on the Greenwich Meridian site and the Journal of Geodesy. This third requirement is strictly on the honor system. :) Feel free to post an optional picture of yourself standing on the "real" GPS meridian as well.

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