The View from Here


Watching the Night
June 14, 2009, 10:23 am
Filed under: Astronomy

I guess I’ve always been a night owl.  When I was about 10, I used to stay awake until I thought everyone was asleep, and then get up to sneak around the house.  In later years, out camping or caving with my buddies, I’d enjoy late night star gazing, meteor watching, or searching for herps.

The night Sky

The night Sky

Nowadays, I often head out to the backyard to enjoy the night. For a long time, I’d just go listen to the insect choruses, enjoying the peace and gazing at the stars, waiting for the occasional meteor.  Then, I discovered a telescope on eBay that looked interesting, and cheap.  I was sorely tempted. How much more interesting would the night sky be with a telescope? I took the plunge, and received my 6″ (diameter) Chinese-made Newtonian reflector. (Reflectors use a parabolic mirror instead of a lens to bend the light and magnify the image)

I have worked in natural history museums much of my life, surrounded by planetariums, observatories, and astronomy clubs. I was never attracted much to astronomy clubs, which seemed to be populated by techno-geeks. I was always much more interested in the social life offered by my field-biology compatriots. They seemed like more down-to-earth people, and I was never much of a gadget guy. Even so, I read astronomy books and science fiction, followed the space program, and even got to meet 2 of the Apollo 11 astronauts and handle moon rocks.  I also produced exhibits on astronomy during my career as a museum curator.

So it isn’t really too surprising that I ended up with a telescope. Now I just needed to figure out how to use the thing. The first thing that I discovered was that it made a great excuse for spending much of the night outside.  After learning how to point it, I also re-discovered lots of astronomical objects that I learned about many years ago.  The Orion Nebula is one of the most impressive distant objects a beginner can see.  It is a relatively bright nebula where one can actually see some structure with a small telescope. Most deep sky objects such as nebulas and galaxies appear as faint gray smudges through a small telescope, if you can even spot them through the heavy light pollution in a city backyard.  Many are so dim that they disappear if you stare directly at them. You have to look slightly off to the side, as your peripheral vision is more light sensitive. Of course, the moon moon_10.08_closeris a very satisfying object to explore as a beginner. It is more likely to temporarily blind your night vision rather than challenge your ability to see faint things.  Even with a small scope, you can spend hours exploring mountain ranges and craters. Saturn and Jupiter are also easy to spot as a beginner.  It was soon apparent to me, even as a non-gadget guy, that my cheap Chinese Newt wasn’t going to continue to satisfy.  It was very poor, optically speaking. Still, it was enough to convince me that I should spend more money on a real telescope, and I graduated to a 6″ Meade refractor. Refractors are the “classic” telescope design, basically a tube with lenses at both ends. You look through one end, the light comes in the other. It was a great leap in sharpness for me, and I was amazed at how much more I could see. After I realized what  difference a real telescope could make, I got “aperture fever.”  The bigger the diameter of the telescope and lens, the more light it can take in, giving you a brighter and sharper view.  You can make out fainter, more distant objects such as galaxies hundreds of millions of light years away.  I went from the 6″ refractor to an 8″ Schmidt-Cassegrain design (a modified reflector), and most recently to a 9.25″.   When I win the lottery, maybe I’ll move up to the 14 or 16 inch.

The 6" refractor

The 6" (150mm) refractor

Being a visual artist and a photographer, it was inevitable that I would want to start imaging through the telescope. When I see cool stuff I want to take pictures or make a painting.  I first just tried holding my digital camera up to the eyepiece, and was amazed that I could actually get a serviceable image of the moon (it’s bright enough for a fast shutter speed). Then I got a mount that basically clamped the camera to the eyepiece, which enabled me to take longer exposures. I quickly found that there were some pretty extreme limits to what I could do with my set-up. The beautiful images of galaxies, nebulas and star clusters I’d seen in astronomy mags were very long term time exposures, requiring expensive tracking and guiding equipment (to compensate for the earth’s rotation), and specialized astro-cameras that take multiple frames and combine them into a sharp image. Getting a sharp image of a planet is like trying to photograph a penny on the bottom of a deep swimming pool. The earth’s atmosphere is constantly in motion, blurring what we see in space the same way the water blurs our view of a penny in a pool, except that we’re on the bottom of the pool looking up.

I tried a few photos with my primitive camera set-up. Now I use a T-ring to couple the camera to the scope like a giant telephoto lens. It is still basically a single shot approach the way it was done before digital cameras, unlike the multiple image, sort and stack approach of the more serious astro-cameras. It’s ok for photos of the moon and relatively bright deep space objects, like Orion.  My telescope mount does track objects, but because it is a fork mount rather than an equatorial, it can only do limited time exposures before the image suffers from field rotation.

The Orion Nebula, taken with 9.25" Scmidt-Cassegrain and a Nikon D80

The Orion Nebula, taken with 9.25" Scmidt-Cassegrain and a Nikon D80. The light from Orion, traveling at 186,000 miles a second, has taken 1,500 years to reach my telescope. That's a looooong trip.

There are still some images I want to try, and I’d like to improve my technique.  However, astrophotography is an extremely technical pursuit.  Although it’s rewarding, it isn’t the same simple pleasure as just quietly sitting and observing.  Sitting still for many minutes at a time makes you invisible to lots of night critters. I’ve had raccoons try to climb up into my lap, I suppose to have their turn at the eyepiece.

I  marvel at the vastness of space and time.   It takes light (the fastest thing in the universe) a hundred thousand years just to cross our own galaxy.  While looking at the Andromeda Galaxy (our nearest galactic neighbor), I know that the light entering my eye now left there at about the time that primitive ape-men were roaming the plains of Africa, 2.5 million years ago.  How far is that? You do the math: light travels at 186,000 miles per second, X 60 seconds, X 60 minutes, X 24 hours, X 365, X 2,500,000= a lot of F’n miles. When looking at even more distant galaxies, I may be seeing light that originated when dinosaurs were still roaming the earth. A hundred million light years becomes an incomprehensibly vast distance, and that is only the local neighborhood in the greater observable universe, which extends out 13.7 billion light years.  When looking up at the Milky Way and the Andromeda Galaxy (it is visible to the naked eye on a dark night), I have two feelings: one is the realization of the incredible vastness of space, and the second is a feeling of isolation.  Sometimes I feel stranded on this piece of rock, the rest of the universe out of reach permanently. Even though this world is more than I can explore in my lifetime,  the fact that I am prohibited from visiting others feels like a prison sentence. Even while just looking out at the universe, we are prevented from seeing it as it is at this moment, and can only see images from the distant past.

Sci-Fi notwithstanding, humans are unlikely to ever venture beyond our own solar system.  The fastest object ever created by humans, the Voyager probe launched in the 70’s, is traveling at about 40,000 mph (nearly 20 times the speed of a high-powered rifle bullet). Even at this speed,it would take Voyager 70,000 years to reach the nearest star system, Alpha Centauri, which is “just” 4.5 light years away.  Traveling like a hyper-bullet for 30 years, it has only recently reached the edge of our own solar system.

Here’s Monty  Python’s take on the vastness of space:

The Moon, taken with a 6" refractor

The Moon, taken with a 6" refractor

The Apennine Mtns and Erastothenes

The Apennine Mtns and Erastothenes

Computer art: my imagined view of Saturn from its moon, Titan.

Computer art: my imagined view of Saturn from its largest moon, Titan. Made with Bryce 3D software

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