When I Heard the Learn’d Astronomer
When I heard the learn’d astronomer,
When the proofs, the figures, were ranged in columns before me,
When I was shown the charts and diagrams, to add, divide, and measure them,
When I sitting heard the astronomer where he lectured with much applause in the lecture-room,
How soon unaccountable I became tired and sick,
Till rising and gliding out I wander’d off by myself,
In the mystical moist night-air, and from time to time,
Look’d up in perfect silence at the stars.
When I stepped outside during the darkest of the night on December 26th and looked up to the sky, a humbling sense of insignificance overcame me. The Milky Way, or Vía Láctea in Spanish, appeared in its illuminating magnificence above me. Through my interest in astronomy and courses with the Amateur Astronomers Association of NY, I am somewhat familiar with the night sky of the Northern Hemisphere and can make out a number of constellations, do some simple star-hopping, and observe with the help of the many friendly people. But what I saw on my first night left me speechless for a few moments. The Milky Way shines brightly and vividly in a diagonal. Especially at the center, features like the Coalsack and Eta Carinae Nebulae and the Southern Cross are remarkable. For this picture, I used a Sony A7R II with a Sony/Zeiss 35MM/28 lens. The settings on my camera were 20 seconds with ISO 3200. The shot was taken during a 4-hour long stargazing tour with Jorge Corante, which was extremely entertaining and educating. We were able to observe a large number of celstial objects including Eta Carinae Nebula, Sirius, Canopus, Rigel, Betelgeuse, Tarantula Nebula, Sombrero Galaxy, Centauri A (galaxy), Alfa Centauri, NGC 3532 (open star cluster), Omega Centauri, M 41, M 42, NGC 2516, M 46, 47 Tucanae, NGC 4755 jewel box, and Jupiter. I highly recommended Jorge and his stargazing tour if you are in the area.
Back to the features of the Southern night sky. In addition to some of the brightest stars other discernible objects are the Large Magellanic Could (LMC) and Small Magellanic Cloud (SMC), neighboring irregular dwarf galaxies, which are some 160,000 and 200,000 light years away, respectively. When we look at the light from these objects, we look back in time, as light adheres to the intergalactic speed limit of 186,000 miles/second. When I say speed limit, I mean the fact that nothing in the Universe, as far as we know it today, travels faster than the speed of light. Hence, the light we see from the Magellanic Clouds left there 160,000 and 200,000 years ago. What happened on Earth during that time? 200,000 years ago the first Homo Sapiens is believed to have appeared in Africa and about 170,000, it started wearing clothes. 30,000 years of nakedness? Must have been a lot warmer back then.
Back to the speed of light and the Magellanic Clouds. For simplification, let's ignore that the Universe is expanding at an increasing velocity (thanks, Edwin Hubble). Not only did Hubble, one of the greatest astronomers of the 20th century, figure out galaxies are receding at an increasing speed, but he also categorized galaxies in a classification scheme called the "Hubble Tuning Fork". It classifies galaxies into ellipticals, spirals, and irregulars. Our Milky Way is a "barred spiral galaxy" whereas the Magellanic clouds are irregulars and are thought to have been influenced gravitationally by our Milky Way galaxy.
In the middle of our stargazing tour, around 4:30 a.m. local time, we saw magnificently bright Jupiter in the East. A little bit to the upper left, that bright spot is Mars. Even though Mars and Jupiter are about 371 million miles (4 astronomical units; 1 astronomical unit (AU) is the distance from the Sun to Earth and light travels this distance, 93 million miles, in 8 minutes) away from each other in their orbits around the Sun, they appear to be close, or in "conjunction", separated by about 4 degrees, about the width of your three middle fingers (For a great intro on measuring the sky visit One-Minute Astronomer). Jupiter is a gas giant, the largest planet in our Solar System, and its mass is about 2.5x the combined mass of all other planets. If Jupiter were the size of a basketball, Earth would not be bigger than a squash ball. The Sun you ask? A sphere with a 9-foot diameter. When calculating trajectories for spacecraft on missions, the mass of Jupiter needs to be figured into calculations due to its gravitational effect. Mars, the "Red Planet", is the Earth's closest neighbor and currently host to six orbiting spacecraft and two ground-based rovers.
The picture above was taken at the explora Atacama in San Pedro de Atacama. It is an all-inclusive hotel with its own observatory. One of the natural enemies of astronomers are clouds and even though clouds do not appear often in the Atacama, the night of our observatory tour was cancelled due to them. Other natural enemies of astronomers or astrophotographers are light pollution and anything but a new Moon. The observatory deploys a Meade 16" LX200-ACF for its guided observations.
To help with stargazing (finding celestial objects) and best times for astrophotography (For darks skies, it helps to know when the Moon rises and sets, and when astronomical twilight occurs, when the Sun reaches 18º below the horizon), I used two apps and one website:
1. SkySafari 5 Pro
2. The Photographer's Ephemeris
3. Light Pollution Map.
Footnotes and Links:
Amateur Astronomers Association of New York
Atacama Desert Stargazing
The Hubble Tuning Fork - Classification of Galaxies; NASA & ESA
Low Surface Brightness Imaging of the Magellanic System: Imprints of Tidal Interactions between the Clouds in the Stellar Periphery.
One-Minute Astronomer: Measuring the Sky
Explora Lodge Atacama