STF 1536 (Iota Leonis) is a quadruple system located 78 light-years away from the Sun. The system consists of a primary component, a yellow-white subgiant of spectral class F3IV, with an approximate mass of 1.7 solar masses and a diameter of 2.1 solar diameters. The primary component itself is a spectroscopic binary. The first companion is a main-sequence star of spectral class F or G (sources differ) with a mass of approximately 1.08 solar masses. The primary and secondary components orbit their common center of mass with a period of 186 years. Another companion is an 11th magnitude star with a separation of 331" from the primary component and a position angle of 346°. According to the WDS, it is gravitationally linked to the primary component, likely a Common Proper Motion (CPM) member.

72 mm - The brightness difference between components A and B is approximately 2.7 magnitudes, and they are separated by just over 2". A telescope with a small aperture might encounter resolution issues under these parameters. However, due to the high brightness of components A and B, their separation was eventually achieved. Even at 96x magnification, a brightening was observed on the first diffraction ring at a position angle of approximately 90°, indicating the potential for resolution at higher magnifications. Ultimately, the components were confidently resolved at 216x magnification. Despite its 11th magnitude, component C, located 331" away from the primary component, is easily visible.