Pluto and Barnard 92
Pluto. No matter how you think of it, dwarf planet, regular planet or isolated world on the remote outskirts of the solar system, Pluto’s presence is indisputable. It was there yesterday, its there today and it will be there tomorrow. Since its reclassification in August 2006, the subject of Pluto has stoked public interest in a way not seen since the announcement of its discovery 80 years ago.
Trying to view Pluto through a telescope can be quite difficult. Ordinarily, it appears ’star-like’, a faint point of light that will not resolve into a planetary disc. Without a detailed set of charts to guide your observation, it can be hard to identify Pluto hidden in the midst of a rich star field.
The classic method of finding solar system bodies – minor planets, asteroids, comets, etc. is to make repeated sketches or photographs of an area of interest. Because they are so far away, our view of stars remains unchanged. So, any object that shows movement becomes a discovery candidate. The same technique was used to discover Pluto.
In early 1930, Clyde Tombaugh was nearing the one year mark of a survey to photograph regions of the sky along the plane of the solar system. With painstaking care, he worked through the zodiacal constellations, taking pictures of the same areas several days apart. He then used a blink comparator to check the images and see if anything moved within the frames. One day, while blinking frames taken in Gemini, he spotted a shifting point of light and the rest is history.
This year, Pluto can be found in the constellation Sagittarius, the Archer. To stargazers, Sagittarius is an observer’s delight chocked full of star clusters and nebulae. Many of these gaseous nebulae are intense regions of star formation – labor and delivery for the Milky Way Galaxy. But there is another type of nebula, cold clouds of interstellar gas and dust known as dark nebulae.
In recent weeks, Pluto’s path has carried it across a couple of dark nebula in the northwestern part of Sagittarius. On the 4th of July, it began a transit across an inky black patch of sky designated Barnard 92. Like other dark nebulae, Barnard 92 blocks light from distant stars creating the appearance of a void or hole in the Milky Way.
Knowing that there wouldn’t be another chance to catch Pluto in such an obvious position for another 248 years, I went out in the early morning of July 9th to image it. Admittedly, the picture may not look like much, but to think that this tiny speck of light represents an object nearly 3 billion miles away with a size smaller than our moon, I can’t help but wonder about what else is out there. Thankfully, we don’t have to wait very long to learn more about Pluto and its icy brethren. If all goes well, the New Horizons probe will begin its visit to Pluto in 2015.
Pluto transits Barnard 92
