Saturday, February 23, 2008

How to get started in amateur astronomy. Step 1: Get real

I've already described how my advent into amateur astronomy was delayed by 20 years by unrealistic expectations. In my case, the expectations were that astronomy requires a telescope and is necessarily expensive, neither of which is true. But I suspect that many people "take up" astronomy--in a very limited, hardware-oriented fashion*--and then drop it because of other expectations that are no more accurate. I have two such in mind, and I'll explain them both.

* By buying a telescope on impulse, or getting one as a present, and then finding it difficult and unrewarding to use. More on this in future installments, and at the end of this one.

The first unrealistic expectation is that stargazing will be effortless. It won't be. Some things are easy, but they're still not effortless. You can see the Galilean moons of Jupiter just by walking outside and looking through binoculars. Ditto the Andromeda Galaxy and the Double Cluster in Perseus, all of which are probably in most amateur astronomers' top ten. But even for the easy stuff, you have to know where--and when--to look. Other things are harder, and all the more rewarding because of the skill and effort that goes into their finding. So here's the first filter: if you're not willing to spend a few evenings learning the constellations, go do something else.

The obvious retort is that you don't have to know the constellations anymore, because computerized telescopes will find stuff for you. That's true, but computerized telescopes are not the push-button-go dreams that they are marketed to be. Most of them have to leveled and aligned, and maybe even pointed at a few known reference stars, before they'll show you stuff. Sounds fun, huh? And dig the irony: you have to know how to find stuff on your own to set up the computerized scope that is supposed to find stuff for you. I can see a way to save yourself a few hundred dollars...

Now, there are computerized telescopes that use GPS and don't have to be leveled and aligned. You really can just turn them on and rock out. They also start around two grand. If you'd rather spend that kind of money than learn your way around the sky, go nuts--just be aware that you're not in my target audience.

The second unrealistic expectation is that the views from your back yard will look like pictures in books and on the web. No backyard telescope is going to give you Hubble-like views, for at least two reasons. The first is that the gorgeous photos of the Orion nebula and the Messier galaxies are all long exposures. Cameras, whether they use film or CCDs, can build up brighter and more colorful pictures than can the human eye, no matter how big the telescope you're looking through. Color in particular suffers, because galaxies and nebulae simply don't have enough of it to register on your retinas. Colorful stars, like red Betelgeuse and blue Rigel, both in Orion, are another matter, and they are among the most striking things in the sky whether you use a telescope, binoculars, or the good ole Mark 1 eyeball.

The other reason that your views will not look like the pictures you've seen is that the telescopes used by professional astronomers and the most advanced amateurs are almost always fantastically large and expensive compared to whatever you'll be looking through. A good starter telescope probably has an aperture between 2.4 and 6 inches (60-150 mm), whereas Rob Gendler takes most of his pictures with 12.5 and 20 inch Ritchey-Chretein scopes (the 12.5" starts at $17K, not including mount, cameras, etc.). But don't despair. As Guy Consolmagno and Dan Davis wrote in Turn Left at Orion (p. 202):
Galileo discovered the four major moons of Jupiter (forever after called the "Galilean satellites" in his honor); he was the first to see the phases of Venus and the rings of Saturn; he saw nebulae and clusters through a telescope for the first time. In fact, a careful checking of his observations indicates that he even observed, and recorded, the position of Neptune almost 200 years before anyone realized it was a planet. He did all this with a 1" aperture telescope.

Charles Messier, who found the hundred deep sky objects in the catalog that bears his name, started out with a 7" reflector with metal mirrors so poor that, according to one account, it was not much better than a modern 3" telescope. His later instruments were, in fact, 3" refractors.
If you've never seen the Galilean moons or the rings of Saturn for yourself, it is hard to explain what a rush it is. I can download gigabytes of Saturn pictures from Voyager and Cassini, but none of them carries the same visceral impact as even the smallest, blurriest view of Saturn through my telescope. It's like the difference between looking at a mounted dinosaur skeleton on the other side of the rope, and holding a chunk of fossilized bone in your hand for the first time, even if it is small, busted, and ugly :-). And I know I'm not the only one who feels this way. Most of our houseguests get a peek at whatever is up, and so far every one of them has been blown away.

The pleasure and satisfaction of amateur astronomy do not come from APOD-worthy views or from instant gratification. Rather, they come from finding and seeing things for yourself, and the enjoyment of doing so is proportional to the effort invested. (In these ways, amateur astronomy is no different from any other human pursuit, be it painting or fixing toilets or building relationships.)

Finally, be patient. You can't learn the whole night sky in one go. It may be possible to run out and buy a telescope and be blasting through the skies by bedtime, but it's neither likely nor recommended. Craigslist, eBay, and attics and closets across the planet are home to thousands of impulse-buy telescopes, and most of them are not worth the paper their breathless ads were printed on (or the pixels they were splashed across). Don't buy a telescope. Not yet. If you're just starting out, you don't know what kind of telescope you'll want, you don't know what to point it at, and you probably don't even know if you enjoy observing. The sky will be there for the rest of your life and far beyond, and there will be no shortage of telescopes around when and if you decide to buy one. But there are some things you need to know first, and that's where I'll pick up next time.

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1 Comments:

Anonymous Sean said...

Hey Dr.Vector, great blog, extremely helpful! and greetings from JHB, South Africa :)

1:45 PM  

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