Some time ago, I said two of the things I would like to have in a PSK are a measuring tape and a set of sine tables. <br><br>I decided that a table of tangents would make more sense, so I generated such a table in Excel. (Described below for anyone who wants it.)<br><br>To use the table, set up a vertical stick and monitor the shadow it casts. At the equinox, the angle the sun makes with the stick should be equal to your latitude. <br><br>To compute this, measure the length of the shadow at its shortest point and divide it by the height of the stick. Obviously, the ground has to be level and the stick has to be absolutely vertical (or you can use a plumb line). This value will be the tangent of your latitude; find the closest value in the table and read off the corresponding degrees and minutes.<br><br>For example, supposing the shadow cast at noon is exactly 1 foot in length and the stick is exactly 3 feet high. Divide 1 by 3 to get 1/3, or .33333...<br><br>The closest value in the table is 0.33; the corresponding entry in my table is <br><br>0.33 18.26288994 18 16<br><br>giving a latitude of 18 degrees, 16 minutes.<br><br>My table only goes to 45 degrees, but that's no problem. Above 45 degrees latitude, the shadow will be longer than the stick. Simply divide the height of the stick by the length of the shadow, find the value as before, and subtract it from 90 degrees.<br><br>For example, suppose the 3-foot high stick casts a 4-foot shadow at its shortest point. 3 divided by 4 equals .75, for which the entry is<br><br>0.75 36.86989765 36 52<br><br>giving a value of 36 degrees 52 minutes. We have to subtract this from 90 degrees, which gives us a latitude of 53 degrees, 8 minutes.<br><br>Of course, this is only valid, strictly speaking, at the spring or autumn equinox (i.e. when the sun is directly over the equator at noon). But if you can relay your position to Search and Rescue by radio, they should be able to apply the correction and at least have a good idea where to start looking. And the mental exercise will keep you warm :-)<br><br>The Excel Spreadsheet<br><br>After some thought, I realized the simplest way to generate this table would be to list all the values from 0 to 1, in increments of .01, and take the arctan (inverse tangent) for each.<br><br>In cell A1, write "Tangent". In cell A2, write "0.01". (There's no need to write down the tangent for 0; it's zero degrees.) In cell A3, write "=a2+.01".<br><br>In cell B2, write "=degrees(atan(a2))".<br><br>In cell C1, write "Degrees". In cell C2, write "=trunc(b2)"; ;this gives you the integer portion of b2, which is the number of whole degrees.<br><br>In cell D1, write "Minutes". In cell D2, write "=round(60*(b2-c2),0)". This gives you the number of minutes, rounded off to the nearest whole number.<br><br>Now select the block (a3..d100) and press Ctrl-D (for Fill Down). The resulting table should look something like this:<br><br>Tangent Degrees Degrees Minutes<br>0.01 0.572938698 0 34<br>0.02 1.145762838 1 9<br>0.03 1.718358002 1 43<br>0.04 2.290610043 2 17<br>0.05 2.862405226 2 52<br>0.06 3.433630362 3 26<br>0.07 4.004172941 4 0<br>0.08 4.57392126 4 34<br>.....