The sun rose over Downtown Pittsburgh Tuesday morning, just as it had Monday. As the fog… The sun rose over Downtown Pittsburgh Tuesday morning, just as it had Monday. As the fog climbed slowly off the river and into the city, just as it had hundreds of times before, it looked like an ordinary morning.

But then something extraordinary happened, something that hadn’t happened in 122 years: Venus wedged itself between the Earth and the sun.

The planet that shares its name with the Roman goddess of love completed its first solar transit since Dec. 6, 1882. Considered an extremely rare event, even by astronomical standards, Venus’ path will run over the sun once more on June 6, 2012. But following that, a transit will not occur until Dec. 11, 2117.

The Friends of the Zeiss, an organization formed for the preservation of observational equipment such as the Zeiss II Planetarium Projector, provided safe public viewing from the upper platform of the Duquesne Incline early Tuesday morning.

Since staring directly at a solar transit of a planet can lead to permanent damage of the human eye, the Friends of the Zeiss employed a projection method of viewing for onlookers. Several telescopes cast shadow rings, images of the sun, on screens and papers held just inches away from the instruments. When the transit began, Venus appeared like a beauty mark on the face of the sun, a small mole of a shadow on each of the screens.

The phases of Venus’ transit are referred to as four contacts. First contact is when the planet breaks the outer rim of the sun, which occurred while the sun was still beneath the horizon for Pittsburghers. Second contact takes place when Venus is first fully encapsulated by the sun. Third contact, which happened at 7:05 a.m., is the first crossing of Venus as it exits the face of the sun. And fourth contact is when it has finally passed and completed its transit.

Prior to third contact, local astronomers counted down to a long-awaited occurrence known as the Black Drop Effect, in which a visible bridge of shadow forms between Venus and the edge of the sun. Francis Graham, Friends of the Zeiss member and astronomy professor at Kent State, discussed a possible explanation for the effect while the crowd waited to see the rare phenomenon.

Unfortunately for them, the Black Drop Effect either did not occur or was invisible to the telescopes used at the incline Tuesday, as only traces of the anticipated teardrop shape could be seen.

As the small shadow of Venus inched across the screen, Graham went on to explain the finer points of the planet to his audience. He described it as “the prototypical greenhouse” because its high levels of carbon dioxide prevent heat from escaping the atmosphere once absorbed from the sun, making it the hottest planet in our solar system despite not being the closest planet to the sun.

“Venus is so hot, lead melts at the surface,” Graham said. He added that next to the sun and moon, it is the brightest object in our sky. Others watched the transit eagerly, while one man celebrated it.

Miguel Sague, a member of the Cancy Indian Spiritual Circle, began the day by singing the sun up with his personal power song, then arranged a sacred circle and burnt copal with sage to purify the air. Sague, who is part Mayan and part Taino, gave a Mayan spiritual explanation for the day’s happenings, in which Venus represents one of two sacred twins who battle the forces of negativity. Sague said the conjunction of the sun and Venus represented an extremely important segment of the ancient mythology because it was a visual “dramatization in the sky.”

Fourth contact occurred shortly before 7:30. The sun stood unblemished once again and although the path of Venus will run over the sun again in eight years, Graham estimated that the nearest place its transit would be visible is the west coast.