Astronomy Night in Sedona

February 12, 2016

The December Sedona Westerners Tracker Hike was an evening of enjoying the stellar beauty of Sedona’s dark skies. The event was organized by the Westerners’ Tracker Boss, Helen Ducharme, and hosted by AJ and Peg Cook.

Prior to viewing the stellar objects chosen for that evening, Mark Ducharme and AJ Cook conducted a slide show presentation to provide information on each star, planet or galaxy we were to observe that evening. The purpose of the presentation was also to give a perspective of the vastness of the universe. With their presentation, Mark and AJ reminded the group why “light years” have been used to measure the astronomical distance rather than miles. For example, Proxima Centauri, the star nearest our own sun, was approximately 26,000,000,000,000 miles away. That’s a lot of zeros! Clearly miles would be far too cumbersome to use as a measurement. So a more convenient method, the light year, had been used to measure interstellar distances.

A light year is a unit of astronomical distance equivalent to the distance that light travels in one year, and is approximately six trillion miles. Proxima Centauri is about 4.3 light years away from our sun. Because of the extreme vastness of the distances involved, the concept of using light years makes understanding interstellar distances much simpler. Using the opportunity to look through a professional size telescope, AJ Cook then showed the group some of the most magnificent stars, planets and other objects visible that evening. His telescope was a fork mounted Celestron CPC with an 11 inch mirror. It used a Schmidt-Cassegrain optical system and GPS computer with automated tracking technology. The telescope was mounted on a permanent pier". He usually views using an eyepiece giving 150 power magnification.

Uranus was the only planet viewed that evening. It was the seventh planet from our sun and was discovered by the astronomer, William Hershel, in 1781. It was also the first planet discovered by telescope. The orbit of Uranus around the sun was found to take 84 years, with 27 moons were discovered orbiting Uranus.

The group was treated to a view of a double star system, Albireo, located in the constellation Cygnus and was approximately 430 light years from Earth. Albireo was a great example of a double star system, with the stars rotating around each other. With the naked eye, Albireo appeared as a single star. From the telescope it was clear these were two stars; one star appeared gold and the other appeared blue. The color differentiation was vivid through the telescope.

The leaders then turned the group’s attention to two nebulas in our galaxy. A nebula was a cloud of dust of hydrogen, helium and other ionized gases. The first nebula viewed by the group was the Dumbbell Nebula

The Dumbbell Nebula is a planetary nebula discovered in 1764 by Charles Messier. Planetary nebulae are formed when stars eject their outer envelopes, exposing the hot core of the star. The exposed core then ionizes the surrounding cloud of expelled material. The clouds keep expanding until they dissipate into the surrounding space.

The second nebula the group viewed was the Orion Nebula. It is one of the brightest nebulas visible from Earth and situated about halfway down the line of stars that form Orion’s Sword. The new stars forming in this nebula are part of what astronomers call an open cluster. When all of the stars are fully formed, what remains is a special tight grouping of four newly born stars called the Trapezium.

Viewing the Orion Nebula segued into viewing the Pleiades star cluster. Ancient Greek mythology described that the Pleiades were the seven daughters of the titan, Atlas, and the sea nymph, Pleione. After Atlas was forced to carry the heavens on his shoulders Orion began to pursue all of the Pleiades. Zeus transformed them first into doves and then into stars to comfort their father. The constellation of Orion was said to still pursue them across the night sky.

The Pleiades star cluster is 440 light years from Earth and most people can see only the seven brightest stars that represent the Seven Sisters. However, with the telescope the group could see that this open star cluster is composed of hundreds of fainter stars. A representation of the Pleiades star cluster is used as the corporate symbol for Japanese car manufacturer, Subaru.

The clear night skies made it a wonderful opportunity to view these magnificent sights in the beautiful Sedona skies.

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