STF 60 (Eta Cas) is one of the nearby binary systems, located only 19 light-years from the Sun. The primary component A is a G1V main-sequence star (some sources suggest F9V) with a mass of 1.08 and a diameter of 1.06 solar masses. It is a star almost identical to the Sun. The companion B is a red dwarf of spectral class M0V, with a mass of 0.63 and a diameter of approximately 0.6 solar masses. The stars orbit around their common center of mass with a period of 479 years. Some sources suggest that the primary component itself is a spectroscopic binary, but this is unconfirmed. Due to its proximity to the Sun, STF 60 has been a frequent target in the search for exoplanets. However, no confirmed exoplanet discoveries have been made in approximately 17 years.

100mm - _STF 60 is a suitable object for observation with small telescopes. Despite a relatively large difference in brightness between the components (almost 4 Mag), the separation of 13.4" is sufficient for easy resolution of the components even at moderate magnification. The nearly two spectral classes' difference shows a color contrast between the components. I observed the primary component as dark yellow and the companion as light orange.