navigating+in+poor+visibility

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=Navigation in poor visibility = toc **poor visibility = cannot see the horizon**

//Please// do not wait until you are caught unexpectedly in poor visibility before trying out your navigation skills - practice them in conditions where you do not really need them to build up you competence and confidence.

The same approach to navigation should be applied when navigating in poor visibility. The main difference is the potential consequence of getting it wrong when the visibility is bad - make things as easy as you can for yourself and assume you will make errors.
 * 1) Think twice before you set off - do not go out in conditions for which you are not equipped (kit and skills) - and do not oworry about "losing face" if you call off or turn back on a walk.
 * 2) Make the legs shorter
 * 3) Choose the easier to follow route rather than the fastest route - use handrails as much as you can
 * 4) Double check every fix - get someone else to check your navigation all the way through if there is someone else who can do this - and every bearing
 * 5) Concentrate on collecting ("tick" features) and use contour changes that are within vision
 * 6) Don't blindly follow a GPS bearing - it may take you over dangerous ground you don't see until too late.
 * 7) If you think you may have gone wrong - STOP rather than carrying on optimistically. Work through relocation techniques until you are happy you have found your position.
 * 8) Try to avoid becoming lost by working hard at keeping track of where you are - ensure someone is timing/pacing to help you appreciate distance covered since the last fix, and pay very close attention to any features youo pass/change in slope.

Winter navigation (BMC): [| 32_winter_nav.pdf]

Following bearings in poor visibility
A way of following a bearing in limited visibility when there are two or more in the group is: 1) Double check whether the bearing you have is magnetic or grid. If the latter adjust for magnetic variation (add 2 in UK). <span style="font-family: Georgia,serif;">2) Set the compass housing so the magnetic bearing is on the compass housing next to the direction of travel arrow. <span style="font-family: Georgia,serif;">3) All member(s) of the group except the "navigator" stay still. <span style="font-family: Georgia,serif;">4) The navigator attempts to follow the bearing as well as possible given that there will probably be no fixed points to aim at. They must remain close enough to the other member(s) of the party that they do not lose sight of each other. <span style="font-family: Georgia,serif;">5) The navigator stops and turns to face the other member of the group and turns the compass so that the south (white) end of the needle is pointing to north on the compass housing. (This is equivalent to taking a back bearing but removes the possibility of errors with mental arithmetic). <span style="font-family: Georgia,serif;">6) The navigator follows the compass direction of travel arrow and they move laterally until it is pointing directly at the other member of the group (this is why it is vital the other member stays still in this phase). <span style="font-family: Georgia,serif;">7) Once the navigator is happy that the back bearing is pointing straight at the other member they make a prearranged signal and the other member moves forward to join them (the navigator must remain still in this phase). <span style="font-family: Georgia,serif;">8) The process is repeated.

<span style="font-family: Georgia,serif;">Many descriptions describe the navigator staying still and sending out another member of the party and then directing them to move right or left until they are on the correct bearing. The nethod described above, though, leaves the navigator (who should be the most competent member of the group) to do the "work" and eliminates the need for any signals/communication other than the one that indicates it is time for the rest of the group to move forward to the navigator.

<span style="font-family: Georgia,serif;">If there are two (or more) competent navigators in the group then the two techniques can be combined - so that the person who initially stays behind and is used for the back bearing, when called forward, goes past the person who went out first and then takes a back bearing on them.

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<span style="font-family: Verdana,Geneva,sans-serif;">Celestial navigation


media type="youtube" key="nyRpBgLeYGg?fs=1" height="385" width="480"

<span style="font-family: Georgia,serif;">[|site that calculate age of moon for given date]

<span style="font-family: Georgia,serif;">A rough guide to direction can be found in a crescent moon - a line joining the "horns" of the crescent will point to south on the horizon. This method is least accurate when the moon is close to the horizon. <span style="font-family: Georgia,serif;">[|Using the moon to navigate]

<span style="font-family: Georgia,serif;">video demonstrating the tilt of the earth's axis of rotation compared with the path of its orbit and the way this gives rise to seasons. also relevant to navigation with the sun <span style="font-family: Georgia,serif; line-height: 0px; overflow: hidden;">media type="youtube" key="DuiQvPLWziQ?version=3" height="360" width="480"

<span style="font-family: Verdana,Geneva,sans-serif;">Links
<span style="font-family: Georgia,serif;">[|Night time navigation]