W. R. Brooks (Phelps, New York, USA) discovered this comet in the evening sky on 1886 May 23.2. He described it as a large, nearly round, and feebly luminous spot with a slight condensation occasionally visible. Although he immediately telegraphed an announcement, he noted that the comet was "suspected." Brooks confirmed the find on May 24.13.
The comet had already passed closest to Earth, but was still approaching the sun. There were numerous observations on May 25. E. Millosevich (Rome, Italy) said the comet was faint and difficult to observe. E. W. L. Tempel (Arcetri, Italy) said the comet resembled a round nebulosity and was 2 arc minutes in diameter, with a speckled condensation. E. E. Barnard (Nashville, Tennessee, USA) said the comet was "faintish" and pretty large in a 15-cm refractor. H. A. Kobold (Strasbourg, France) said the comet was a faint and round nebulosity about 1 arc minute across. He added that a point-like condensation was occasionally visible. On May 26, J. Palisa (Vienna, Austria) observed with a 30-cm refractor and said the comet was faint and 2 arc minutes across. He noted it was very faint and difficult to see in the same telescope on the 28th and hardly seen in the 76-cm refractor on the 30th. On May 31, F. Gonnessiat (Lyon, France) observed with a 15-cm refractor and described the comet as a faint luminous spot about 1 arc minute across, with a central condensation. C. Trépied (Alger, now al-Jazâa«ir, Algeria) saw the comet with a 50-cm refractor on June 2 and 3, and described it as an ill-defined nebulosity, with hardly a trace of a central condensation. Palisa observed the comet with the 69-cm refractor and described it as extremely faint on the 3rd. Interestingly, Barnard continued his observations with smaller telescopes than Palisa. He observed with a 15-cm refractor on the 25th and wrote, "Not very faint. Dim and large." On the 29th, Barnard observed with a 13-cm refractor and said the comet was pretty faint.
The comet was last detected during the first days of July. Barnard described it as not very faint and still large in a 13-cm refractor on the 2nd. The final observations of this comet were obtained by H. C. Russell (Sydney Observatory, Australia) on July 3.46, by Tempel on July 3.89, and by astronomers at Nice on July 3.90. Russell simply described the comet as "very faint."
The first parabolic orbit was calculated by S. Oppenheim using positions from May 25, 28, and 30. The resulting perihelion date was 1886 June 3.37. H. Oppenheim took positions from May 26, 28, and 31, and gave a perihelion date of June 2.27. The first elliptical orbit was calculated by S. Oppenheim. Using positions obtained through July 1, he revealed a perihelion date of June 7.28 and a period of 9.05 years. J. R. Hind used a similar set of positions a short time later and determined a perihelion date of June 7.07 and a period of 6.30 years. The most recent orbit was calculated by R. J. Buckley (1979). Using 39 positions spanning the entire period of visibility, he found a period of 5.44 years, but noted that the positions were badly spread across the relatively short observation arc, thus making a likely uncertainty of 1-2 months.