A vertical type sundial can be found mounted on a wall of a house in St Mary Street Ghaxaq, behind the parish church. It is very near the Dar tal-Bebbux, a building with a façade decorated with mollusc shells.

It is not a major restoration project by Din l-Art Helwa but it is considered significant as the features of the sundial were nearly completely eroded beyond repair.

The late Paul Micallef of Fgura conducted a detailed survey of existing sundials. His 1994 publication Maltese Sundials inspired Dr Alexander Cachia Zammit, then Malta’s Ambassador to the Holy See, to approach Din l-Art Helwa with an offer to sponsor the full restoration of the Ghaxaq Sundial.

The sundial was in a pitiful state with its features fading away by erosion. It was masked by power lines and practically undetectable. The original designer and date are not known but with the hour lines and numbers slightly engraved it is very likely to be more than 100 years old. The orientation of the sundial is towards south and its dimensions are 91cm by 83cm.

Restoration by Din l-Art Helwa was carried out under the supervision of Mr Paul Micallef himself. The restored sundial was unveiled in January 1996 by the Mayor of Ghaxaq in the presence of Din l-Art Helwa officials.

Vertical sundials are commonly mounted high on walls of buildings. The face may be painted, or displayed in inlaid stone. Some vertical sundials are mounted with two faces on a corner providing the time throughout most of the day.

The fixed axial gnomon is often a single metal bar, or a tripod of metal bars for rigidity. If the wall of the building does not face in a cardinal direction such as due south, the hour lines must be corrected. As the gnomon’s style is aligned with the Earth’s rotation axis, its angle with the horizontal must be equal to the sundial’s geographical latitude.

Notwithstanding its rather small size, Malta holds a considerable heritage of different sundials.

The greatest concentration of sundials are found in the village of Rabat. There are 12 of them. Five of these are distributed around the courtyard of the Dominican Priory. Fr Benedetto Castronius designed four of them in 1717. They were later restored in 1822.

Valletta has two sundials. One is at the rear end of the Jesuits Church in St Paul’s Street. This is one of Malta’s oldest and needs to be regularly maintained.

The other sundial is in Republic Street, in the heart of the city, on the façade of the Casino Maltese. Its designer was Rev. George Fenech who designed quite a few sundials across Malta. This is a Noon-Mark sundial measuring 6.1m x 1.9m featuring all the signs of the Zodiac and the calendar months. These types of sundials do not indicate the hours. The gnomon is a circular disc on a fixed rod with a hole in the centre. A sunbeam passing through the hole produces a spot of light on the sundial face. When the spot touches the part designated for the current month, this indicates that it is 12:00 noon.

It should be stated that these instruments are not that precise. However, centuries ago, such dials were used to correct mechanical clocks, which were sometimes even more inaccurate.