Editing Vulcan (hypothetical planet) (section)

=== Attempts to confirm the discovery ===
Numerous reports reached Le Verrier from other amateurs who claimed to have seen unexplained transits. Some of these reports referred to observations made many years earlier, and many were not dated, let alone accurately timed. Nevertheless, Le Verrier continued to tinker with Vulcan's orbital parameters as each newly reported sighting reached him. He frequently announced dates of future Vulcan transits. When these failed to materialize, he tinkered with the parameters some more.<ref>Jay B. Holberg, Sirius - Brightest Diamond in the Night Sky, Springer New York · 2007, pages 53-54</ref>

Shortly after 08:00 on 29 January 1860, F.A.R. Russell and three other people in London saw an alleged transit of an intra-Mercurial planet.<ref>''Nature'', 5 October 1876.</ref> Many years later, an American observer, Richard Covington, claimed to have seen a well-defined black spot progress across the Sun's disk around 1860 when he was stationed in [[Washington Territory]].<ref>''Scientific American'', 25 November 1876.</ref>

No observations of Vulcan were made in 1861. Then, on the morning of 20 March 1862, between 08:00 and 09:00 [[Greenwich Mean Time|Greenwich Time]], another amateur astronomer, a Mr. Lummis of Manchester, England, saw a transit. His colleague, whom he alerted, also saw the event.<ref>{{Cite web|url=http://adsbit.harvard.edu/full/seri/MNRAS/0022//0000232.000.html|title=1862MNRAS..22..232H Page 232|website=adsbit.harvard.edu|access-date=2019-04-10}}</ref> Based on these two men's reports, two French astronomers, [[Benjamin Valz]] and [[Rodolphe Radau]], independently calculated the object's supposed orbital period, with Valz deriving a figure of 17 days and 13 hours and Radau a figure of 19 days and 22 hours.<ref name=Baum/>{{rp|page=168}}

On 8 May 1865 another French astronomer, [[Aristide Coumbary]], observed an unexpected transit from [[Istanbul]], [[Turkey]].<ref name="Coumbary" />

Between 1866 and 1878, no reliable observations of the hypothetical planet were made. Then, during the total [[solar eclipse of July 29, 1878]], two experienced astronomers, Professor [[James Craig Watson]], the director of the [[Detroit Observatory|Ann Arbor Observatory]] in [[Michigan]], and [[Lewis Swift]], from [[Rochester, New York]], both claimed to have seen a Vulcan-type planet close to the Sun. Watson, observing from [[Separation Point, Wyoming]], placed the planet about 2.5 degrees south-west of the Sun and estimated its [[apparent magnitude|magnitude]] at 4.5. Swift, observing the eclipse from a location near [[Denver, Colorado]], saw what he took to be an intra-mercurial planet about 3 degrees south-west of the Sun. He estimated its brightness to be the same as that of [[Theta Cancri]], a fifth-magnitude star which was also visible during totality, about six or seven minutes from the "planet". Theta Cancri and the planet were nearly in line with the Sun's centre.{{citation needed|date=December 2022}}

Watson and Swift had reputations as excellent observers. Watson had already discovered more than twenty [[asteroid]]s, while Swift had several [[comet]]s named after him. Both described the colour of their hypothetical intra-mercurial planet as "red". Watson reported that it had a definite disk&mdash;unlike stars, which appear in telescopes as mere points of light&mdash;and that its phase indicated that it was on the far side of the Sun approaching [[superior conjunction]].<ref>John C. Barentine, Mystery of the Ashen Light of Venus - Investigating a 400-Year-Old Phenomenon, Springer International Publishing · 2021, page 211</ref>

Both Watson and Swift had observed two objects they believed were not known stars, but after Swift corrected an error in his coordinates, none of the coordinates matched each other, nor known stars. The idea that ''four'' objects were observed during the eclipse generated controversy in scientific journals and mockery from Watson's rival [[C. H. F. Peters]]. Peters noted that the margin of error in the pencil and cardboard recording device Watson had used was large enough to plausibly include a bright known star. A skeptic of the Vulcan hypothesis, Peters dismissed all the observations as mistaking known stars as planets.<ref name="baron" /> {{rp|pp=215–217}}

Astronomers continued searching for Vulcan during total solar eclipses in 1883, 1887, 1889, 1900, 1901, 1905, and 1908.<ref name="baron">{{cite book |title=American Eclipse |author=David Baron |year=2017 |publisher=Liveright |isbn=9781631490163}}</ref>{{rp|p=219}} Finally, in 1908, [[William Wallace Campbell]], Director, and [[Charles Dillon Perrine]], Astronomer, of the [[Lick Observatory]], after comprehensive photographic observations at three solar eclipse expeditions in 1901, 1905, and 1908, stated: "In our opinion, the work of the three Crocker Expeditions ... brings the observational side of the intermercurial planet problem{{mdash}}famous for half a century{{mdash}}definitely to a close."<ref>{{cite journal |last=Campbell |first=W. W. |title=Report of the Lick Observatory |journal=[[Publications of the Astronomical Society of the Pacific]] |date=1909 |volume=21 |issue=128 |pages=213–214}}</ref>