Page "Vulcan (hypothetical planet)" Paragraph 18

These are merely the more " reliable observations " of alleged intra-Mercurial planets.

For half a century or more, many other observers tried to find the hypothetical Vulcan.

Many false alarms were triggered by round sunspots that closely resembled planets in transit.

During solar eclipses, stars close to the Sun were mistaken for planets.

At one point, to reconcile different observations, at least two intra-mercurial planets were postulated.