Explorer 209 Challenge Mystery Cache

This cache is part of the  Explorer Challenge series - as originally conceived by PetersfieldPoodlePosse, and based upon British Ordnance Survey grid squares as depicted on OS Explorer maps. Thanks to Darren (PPP) for help and advice setting up this cache and for the GSAK macro.

The cache is at the published coordinates, close to the centre of the Explorer 209 (Cambridge) map. To complete the challenge, you will need to find, or have found, a total of 105 caches.

The cache has been placed on a permissive footpath close to the Kings Cross/Cambridge railway line. From the top of the bank, you can see the traffic lights at the A10/M11 junction, and the River Cam is about 100 yards away, reflecting some of the key geographical features on the map. The quoted difficulty rating relates to the whole challenge: the actual cache is a standard 1.5.

What is the Explorer 209 Challenge?

	The cache is called the Explorer 209 Challenge because each of the different caches you need to have found to qualify must be in a different British Ordnance Survey grid square as depicted on the Explorer 209 Cambridge map. Most of this series require you to have found as many caches as the number on the map: however, this is a relatively small map and at the time of placing the cache there were only 254 eligible squares. So you are only required to find 105, or half the quota. Extra credit will be given to those who manage 209! The CO had 115 at the time of setting, but has since passed the 209 mark.
	The caches can be of any type, previous finds qualify (including those finds now archived and events attended (even if you were the host)), in fact just about any cache other than those you have placed yourself (more on that later) can be counted.
	To find out more about this and other Explorer Challenge caches, go to www.pppgeo.co.uk/explorer.html which has been created to complement the cache series.

The grids on the map "start" in the south west corner just west of Royston at TL 33000 40000 and "finish" 3 miles west of Newmarket at TL 60000 62000, so giving a possible twenty-seven (33 to 59) easting squares and twenty-two (40 to 61) easting squares. 594 squares in total in which you need to find a cache in 105 different squares to qualify.

Note: for the purposes of this challenge, only complete squares are counted, so the small area around the A10/A14 and the two caches which are on the map but in square TL4762 are ineligible.

To determine which of the squares of the map a cache qualifies for, the British Grid reference is given at the top of each cache page just below the main co-ordinates shown in bold, as circled below.

For the purposes of this challenge the published co-ordinates of all caches, including Unknown/Mystery and Multi caches are those that are to be used when determining which square a cache counts towards

To help those of you that want to plan your finds you can either use the Project GC checker or a GSAK Macro has been written which produces a web page of your finds, example output shown below.

When you have found the 105 caches you need to provide proof of that fact to be eligible to claim a find on the cache; this can be via one of any number of different methods you may have available:

1. Use the output provided by the ProjectGC macro (this is the preferred option)
2. List the cache codes and names in corresponding grid reference order in your found log
3. Create a public bookmark list
4. Send the GSAK Macro generated file to me via my profile or add it to your profile page