Part of the meridional ring, which is positioned parallel to the local meridian.

This quarter of the ring is free space; it has been inscribed with the latitudes of some European cities, for convenient reference ("Wien 48°10, Lissabon 38°50, Paris 48°50").

The instrument is suspended from this loop so that the meridional ring hangs vertically.

The loop slides stiffly around the meridional ring. It is slid until the arrow on it lines up with the latitude of the user, written on the meridional ring.

Part of the equatorial ring. See photograph of reading the position of the sunbeam on the equatorial ring.

Part of the declination "ring", which swivels so that the sunbeam can pass through the hole in the black slider.

See photograph of reading the position of the sunbeam on the equatorial ring.

Slider for setting the season of the year (the declination "ring" is marked in months)

Hole through which the sunbeam passes. The instrument, dangling from the string, is rotated until this sunbeam falls on the equatorial ring. See photograph of reading the position of the sunbeam.

Month label for March. Above it, April, May (hidden by, slider), and June (visible through gap in slider). Below it, January and "February are hidden behind the equatorial ring."

Month label for September. Above it, July and Augustː below, October, November, and December.

Pointer on slider. The slider is slid until the pointer lines up with the correct month. This pointer is only used for the July-December part of the year; January to July are read from the pointer on the other side of the slider.

Pointer, which is adjusted to point to the local latitude (in this case, 50 degrees north of the equator).

This part of the meridional ring is marked with latitudes for the southern hemisphere.