Your journey starts at P1, which is in fact the highest point of the whole trail:
P1N = N48°16,574
P1E = E016°19,997
The inscription on the observatory contains a four digit number which is ABCD.
The coordinates of P2 are:
P2N = P1N-(BC-20)
P2E = P1E+(ABC-22)
At P2 you will again learn some interesting facts. Take the crossfoot of both two four digit numbers on the wall and add them together. The result is F.
The coordinates of P3 are:
P3N = P2N-(F+8)
P3E = P2E+(F*3)+2
At P3 you will find a poem. In order to get closer to the cache you have to count the number of all occurences of the character "g". Let's name the result G. By the way, don't forget to enjoy the fantastic view near this place.
The coordinates of P4 are:
P4N = P3N+(G*80)
P4E = P3E-(G*50)+16
After a short walk you'll reach P4. Especially for you there is a three digit number in about 2.4 meters height which is illuminated at night. The number is L. Please see hint - stage 4 is gone!
The coordinates of P5 are:
P5N = P4N+(L-212)
P5E = P4E+(L-107)
Now you are leaving the marked path. At P5 you will find a stone. Well, not just any stone but a special one. You don't have to find out why the stone is exactly there. Just note the three digit number which is S.
The coordinates of P6 are:
P6N = P5N-S+22
P6E = P5E+(S*3)-98
Besides the really astonishing view you will find the final hint to the cache on the stone wall at P6.
The coordinates of P7 are:
P7N = P6N+???
P7E = P6E-???
Before you leave this place to find the cache I strongly recommend to visit the round view platform which is inside the area.
At the cache location it is possible that you get a bad GPS accuracy, so take your time and examine the ground...
BTW: The cache is hidden around 20 meters away from P7. From this position go uphill (or to be more precisely, head for the cache at ~218 degrees).
The cache is a 15x15cm box.