Zmanim Map

Did you ever find yourself unsure of the correct bearing (direction) to Yerushalayim (Jerusalem)?   The new Zmanim/Bearing to Yerushalayim map will help you find it very easily.  The map draws two lines from your location to Yerushalayim. The blue line uses the commonly used (Levush and others) rhumb line (a straight line on a Mercator projection map), while the green line shows the great circle route (Emunas Chachamim and others) on a map.   While it appears that the circle line is not a straight line, on a globe, the shortest (and straightest) line between two points follows the great circle route.   Future posts will detail the technical aspects of the work involved.   For additional information of the correct bearing for tefila, see Rabbi Yehuda Herskowitz's article in Yeshurun volume III pages 586-602 and Gevuras Moishe on Bava Basra / Kivun Batfila by Rabbi Gavriel Moshe Goetz.   Elozor Reich wrote a very nice article on the subject titled Which way shall we turn?.

How to Use

Find your exact location on the map by dragging the marker to your exact location or by clicking anywhere on the map. You can also click on the search button and enter your location (such as "Lakewood, NJ" (the default), "Vilnius, Lithuania") or just enter a zip code (Canadian or British postal codes work as well) to zoom in on your location.   Changing to satellite view and zooming in farther will make the job easier (assuming that you can identify your roof).   Once the red marker is centered on your location, click the red marker to show your exact latitude, longitude and bearing to Yerushalayim in an info window.   There are two additional tabs that show today's zmanim.   You can click on the "Link" button to refresh the page with the URL that contains coordinates to the currently displayed map with it's zoom level so that it can be bookmarked or emailed.
I would like to thank Rabbi Yehuda Herskowitz for his excellent article and additional information that he provided.