PETAL_MS_SCOUTER 10 Posted April 21, 2003 Share Posted April 21, 2003 Is there a website or other source out there that gives declination for various locales? I was looking at an old Scout Fieldbook that gave them for 1985, but noted that the readings change over time. I recently purchased a couple of maps that did not show any declination in the margins. Help ! Link to post Share on other sites
le Voyageur 72 Posted April 21, 2003 Share Posted April 21, 2003 No need for a chart on declination...here's how to find it in the field. Set your compass to N and aim it at Polaris (true North), the needle will then point to Mag North giving you your declination for your area.... Link to post Share on other sites
eisely 13 Posted April 21, 2003 Share Posted April 21, 2003 le V's method clearly will work, but it will only be as accurate as your compass. I am somewhat surprised that your maps had no declination data in the margins. What was the scale of these maps? Were they USGS maps? Did they possibly have a compass rose imprinted somewhere on the map? I am not aware of a web site that gives such information but I am sure such must exist. Link to post Share on other sites
eisely 13 Posted April 21, 2003 Share Posted April 21, 2003 Did you try this website? This appears to provide avenues to many methods for determining the declination for almost any location. http://www.geocities.com/magnetic_declination/#DETERMINE Link to post Share on other sites
acco40 95 Posted April 21, 2003 Share Posted April 21, 2003 Did you know that the "North Star" (Polaris) moves with time? Albeit very slowly, but it does move. I have a hard copy that shows the position of Polaris with time and also has lines of declination for the CONUS (Continental United States). For most major U.S. cities, try: www.timex.com/html/watch_inst_comp_DAUS.html (Note: Jackson Mississippi is 1 deg East)(This message has been edited by acco40) Link to post Share on other sites
KoreaScouter 13 Posted April 22, 2003 Share Posted April 22, 2003 There's another web site, http://www.gislab.lanl.gov.faq.html It has a map of the world, with declination degree lines on it as an overlay. The best thing, though, is to make sure your map has complete margin info...can you get a refund? BTW, a dec angle of 0 degrees obviously makes land navigation, and the teaching of it, much easier. Rumor has it that's why the Army located the Infantry Center at Ft. Benning, GA (yes, dec angle of 0 degrees)... KS Link to post Share on other sites
Eagle74 10 Posted April 23, 2003 Share Posted April 23, 2003 Here are some more for ya: http://www.thecompassstore.com/decvar.html http://www.spacecom.com/customer_tools/html/body_mag_dec.htm http://www.princeton.edu/~oa/manual/mapcompass2.shtml Good information about declination and also other compass topics. Link to post Share on other sites
AK-Eagle 19 Posted April 23, 2003 Share Posted April 23, 2003 You can try this website as well http://www.geolab.nrcan.gc.ca/geomag/mirp_e.shtml the declination in your area change year to year a topographic map here in Alaska can be 5 degrees or more out of date. Link to post Share on other sites
eisely 13 Posted April 23, 2003 Share Posted April 23, 2003 I would expect that kind of fluctuation from year to year in Alaska, but not in the lower 48. Link to post Share on other sites
AK-Eagle 19 Posted April 23, 2003 Share Posted April 23, 2003 Actually what I meant to say was the annual change here in Juneau is a 13'E(minutes East) The "newest" USCGS topo maps here are from the mid 80's with more than a few still in print from the 70's! That is where my 5 degree change from the map came from. Hydrographic (Ship) charts (maps) are printed more often and have the compass rose with the updated rate of change. They and Aeronautical charts also have information about Local Magnetic Disturbance area's. Got a few I know of that swing the needle of cruise ship navigation magnetic compasses up to 20 degrees out. They make for interesting looks on the faces of scouts trying to follow a bearing ;-) Link to post Share on other sites
BEW725 10 Posted August 30, 2003 Share Posted August 30, 2003 I note that my new "toy" (a Garmin Mapquest 76S GPS system) gives declination information and can read out in either magnetic north or true north. Does anyone know how the GPS system determines declination? Is this something that updates over time, or is this something that was programmed into the unit at startup? Bruce Link to post Share on other sites
Eagledad 2777 Posted August 30, 2003 Share Posted August 30, 2003 Hi All >>Set your compass to N and aim it at Polaris (true North), the needle will then point to Mag North giving you your declination for your area.... < That's pretty cool. Learn something new and fun everyday. One other source may be your car owners manual. Some manuals provide declination for adjusting the compass in the car to the local area. Have a great weekend. Barry Link to post Share on other sites
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