Christmas Star 2020

Port Chester Middle School astronomy teacher Jaime Rufo recently gave a one-of-a-kind presentation about a celestial phenomenon that will be at its best in the sky on Dec. 21 — the 2020 Christmas Star.

Typically, she would have made her presentation in the 30-foot planetarium at PCMS, but this time she offered her audience a virtual one.

“We can’t get together in our planetarium, but we can get together in my virtual planetarium,” she said.

Viewers logged in via Zoom or watched the Dec. 16 presentation through Facebook Live.

Ms. Rufo shared images of the night sky looking toward the south. She showed where Mars could be found and noted the planet is the “red/orange dot in the sky.” She also shared details about other notable planets and stars that can easily be seen in the night sky.

Near Mars is Taurus, or “the bull constellation,” Ms. Rufo said, showing it on the screen. The constellation also includes Pleiades, or the Seven Sisters, which are “baby stars formed from a nebula. They are young stars. You know this because they have a blue color.”

Ms. Rufo also shared details about the constellation Orion, which she called “another great winter constellation.”

“My favorite star is Betelgeuse,” she said pointing to it in the sky.

Ms. Rufo explained that while it may look like the stars move through the sky, it is the earth that is rotating.

“The Earth rotates around the sun and the earth goes faster than other planets,” she said. “The stars move east to west. The planets are wandering a bit.”

The word planet means wanderer, she said.

“Sometimes they move faster, slower, they move backwards, which is called retrograde motion,” Ms.  Rufo said.

“Amazing,” “cool,” and “wow” were some of the words written in the comment section by viewers as the screen changed to show the variations in the night sky.

All of this explanation was a build-up to the big event.

Beginning in early November, the planets of Saturn and Jupiter began to move closer together in the sky. As the final two months of the year progress, the planets continue to get closer.

“December 21st, this is the full conjunction when Saturn and Jupiter completely cover each other. They look like one big, bright star at 5 p.m. at night,” Ms. Rufo said.

The phenomenon can be seen with the naked eye or with a pair of binoculars or telescope.

It has been hundreds of years since this celestial phenomenon has occurred. Astronomer Johannes Kepler saw it back in 1603.

“They were very excited about this conjunction, but in 1603 it was not a fantastic alignment,” Ms. Rufo said, taking the audience back in time through computer technology to to show them what Kepler and his fellow astronomers would have seen on Dec. 23, 1603.

“It was a really big disappointment for astronomers. They were not able to see the brilliant star we are seeing,” she said.

While it might not have been the most thrilling conjunction, it did inspire Kepler to do some math. He calculations indicated there had been another conjunction around the birth of Jesus Christ, in 7 BCE.

“It would have been very bright,” Ms. Rufo said of this earlier event. So much so, that it could have helped the Magi with directions to find where Jesus was. Ultimately it became known as the Christmas Star.

This event is not something that happens annually, but rather every 400 years or so.

“Hopefully we will have very clear skies on Dec. 21,” Ms. Rufo said, encouraging everyone to get outside around 5 p.m. that day to take a look at the southwestern sky.

While the conjunction was visible through the month, it will be at its peak on the 21^st. After that, Saturn and Jupiter will begin to move away from each other.