Tests with a unique compass device in recent months have established that many of the world's - and even Israel's - synagogues have been built without their holy arks facing the Temple Mount in Jerusalem, even though this is the traditional position for Jewish prayer, The Jerusalem Post has learned. The synagogues have been tested by the world's first and only "Jerusalem Compass," a mechanical solid brass device that points to Jerusalem and the site of the Temple from anywhere on Earth - invented by a New Jersey-born Jerusalem yeshiva student who goes only by the name "Moshe." The Shulchan Aruch, the Jewish legal code compiled by the great Sephardic sage Rabbi Joseph Caro in the 16th century, states (in section 94) that a Jew who comes to pray should face the Land of Israel, and that if he is already in Israel, he should face the site of the destroyed Temple and the Holy of Holies in Jerusalem. If a person is in a windowless room and hasn't a clue where this is, he should direct his prayers from his heart "to God in heaven." Moshe noted that many synagogues have been built abroad with their holy ark (aron kodesh), which houses the Torah scrolls, facing the "wrong" direction - either because the builders did not know where Jerusalem was in relation to its location or because of building ordinance constraints. A married father of six who has a US university degree in music education, Moshe became an Orthodox Jew and studied in a variety of haredi yeshivot here, including Aish Hatorah. He said that in recent months, he and friends have "tested" many synagogues for their position using his Jerusalem Compass and found many with the arks facing the wrong direction. Even in Israel, and Jerusalem, many are significantly off the mark. The synagogue at a well-known haredi yeshiva in the capital, for instance, faces north rather than toward the Temple Mount. "Most Diaspora Jews face the traditional Mizrah (East) when they pray, but if you face east and pray in Florida, Toronto or London, you will be facing totally different spots," he explained. Christian Zionists who love Israel also have the habit of praying towards Jerusalem - or towards where they think Jerusalem is. Conventional compasses always point north because of the magnetic force of the North Pole, but since Jerusalem is always in a different direction depending on where you are, the ingenious Jerusalem Compass has a "magnetic polarity recalibrator" (MPR) to point to the right direction. The $25, non-electrical, non-computerized device - registered for an international patent - appears to defy nature, as the magnetic needle does not always point north. It is pre-calibrated for the continental US (excluding Miami, Hawaii and Alaska). But "log book" code numbers on the inside of the brass cover encompass virtually any other location on the globe. The user recalibrates by releasing the MPR bar, rotating the rim of the compass glass until the needle is opposite the relevant code number on the dial and sliding the MPR bar towards him after recalibration. The setting doesn't have to be changed until you travel to another city in a large country or a different small country. Moshe, who moved to Israel two decades ago and lives in Jerusalem's haredi Har Nof neighborhood, told the Post that he first thought of the need for such a compass when he was studying the Talmud tractate of Succot in a yeshiva in 1991. "We were learning about descriptions of the altar in the Temple, and I was very confused by all the directions given. I thought to myself how it would be possible always to find where the Holy of Holies of the Temple stood. I quickly came up with the concept, but it took me almost 14 years to turn my ideas into an actual product." After he designed it, the inventor went to China - believed to be the original home of the first compass invented during ancient times - to have it manufactured according to his exact specifications. Within a few months, he had designed the compass - with its Star of David engraved on the cover and also positioned under the rotating needle - as well as a key chain attachment, a cube-shaped gift box and instructions, with endorsements from prominent haredi rabbis (Moshe Halbershtam, Moshe Sternbuch and Yosef Lieberman) in Jerusalem. "People I've shown it to are very enthusiastic," Moshe said. "But they are shocked when they find they have been praying for years facing the wrong direction. Those who have the compass now face the correct position to pray even when the aron kodesh is in the wrong place." He has teamed up with the Monsey, New York-based company TES, which also sells Jewish software, to market the device by mail around the world (go into www.jewishsoftware.com and click "Jerusalem Compass.") The device will soon be available in Israel as well. "Moshe managed to bring together all aspects of design, manufacture, graphics and promotion by himself," commented TES Jerusalem representative Jeff Milgrom, who also lives in Har Nof. "It fills a real need, and also will be valued for sentimental reasons because it always faces Jerusalem. I remember recently being in the windowless room that serves as a synagogue at New York's JFK International Airport. Nobody knew in which direction to pray. I pulled out my compass, and it pointed to Jerusalem. Everybody was amazed. It seemed to defy nature."