The larger is of magnitude 3-1/2, the smaller of magnitude 5-1/2; the former orange, the latter emerald.

The companion stars are small, and require a good telescope to be well seen.

Ras Algethi is a variable, changing from magnitude 3 to magnitude 3-1/2 in a period of 66-1/3 days.
The star [rho] Herculis is a closer double.

The components are 3".7 apart, and situated as shown in Plate 3.

The larger is of magnitude 4, the smaller 5-1/2; the former bluish-white, the latter pale emerald.
There are other objects within the range of our map which are well worthy of study.