It is a sundial. A piece of metal casts a shadow on the numbers when the sun shines. As the sun «moves» from east to west – or more precisely – as the earth rotates from west to east, the shadow will move from left (6:00 a.m.) to midway (12:00 midday) and on to the right (6:00 p.m). The high weapon-house roof will, at times of the year, cast a shadow on the sundial in the evenings.
This is another indication that the church, from the beginnings, did not have such an additional building. In the Catholic times, in clear weather, the sundial could have served as a guide to the priests at the masses and prayers – eight in all – they had to perform. In 1973, the sundial was restored by Auden Nedal with a new adjusted brass plate. The letters HT in the upper left corner of the stone may indicate that Hans Nielsen Tausan, a priest interested in astronomy, could have had something to to with the sundial.