STF 1877 (IZAR), stands out as one of the most well-known and beautiful binary systems, positioned at a distance of 202 light-years from the Sun. The primary component of this system is a bright giant of spectral class K0II, with a mass of 4.6 times that of the Sun and a diameter of 33 solar diameters. This star has already depleted its hydrogen reserves and transitioned to a higher stage of evolution. The companion is a white main-sequence star of spectral class A2V, weighing 2.27 times the mass of the Sun and measuring 2.7 solar diameters. The companion is likely itself a spectroscopic binary. The estimated orbital period is 2800 years, although this figure has not been conclusively confirmed.

72mm - STF 1877 is easily found approximately 10° SW of the brightest star in the Shepherd constellation, Arcturus. The nearly three-spectral-class difference between the primary component and the companion manifests as a noticeable color contrast. Higher magnification, in my case, 172x, is required for a clear resolution. I observed the primary component as distinctly orange and the companion as bluish.