In April 1860, an unknown star with a magnitude of 9.7, later designated as T Borealis, was observed in the same field of view as Arcturus. Since then, no one has seen it, but it is not excluded that it may still reappear. It is believed to be a recurrent nova or an irregular variable star. Its position is 14:11 minutes, +19.18.

Please note that the abbreviations for cardinal directions (N, W, S, E) should not be translated into their word equivalents. The combinations of cardinal direction abbreviations should always be translated into combinations of abbreviations in English, for example, ZSJ should be translated as WNW, VJV as ESE, JV as SE, ZJZ as WSW, VSV as ENE, SZ as NW, JJZ as SSW, SSV as NNE, SV as NE. The abbreviation for IAU constellation code should not be translated. "Boční vidění" should be translated as "averted vision".