The Ales Stenar, known in English as the Ale’s Stones, is an ancient megalithic monument of Sweden. The stones are outlining a ship. The paper
"Astronomical Alignments of Ales Stenar Along Sunset and Moonset Directions"
shows alignments of the stones along the northern possible moonset on major and minor lunar standstills. These astronomical alignments are shown using the Photographer’s Ephemeris. It is possible that this megalithic monument was used for observing the cycles of the moon.
In this image, we can see the left side of the Ales Stenar and the direction of the northern moonset (blue line) on a major lunar standstill, represented by the blue line. Note the alignment of the stones along this direction.
Here, we can see the right side of the Ales Stenar and the direction of the northern moonset (blue line) on a minor lunar standstill, represented by the blue line. Note the alignment of the stones along this direction.
The images are snapshots of the results of Photographer's Ephemeris. In the images, the yellow and orange lines are giving the directions of sunrise and sunset on the days of lunar standstills.
On the summer solstice, we have the main axis of Ales Stenar oriented along the sunset. In the following image, this direction is given by the orange line.