I assume you mean amateur astronomers, not the professional ones who pretty much program their computers to do the work these days and look at pictures later, rather than pressing their eyes against an eyepiece (they have to; they mostly look at things that require hours-long exposures). Their work requires no real explanation. It is useful basic science that is part of physics. It also has almost nothing to do with the amateur kind.

Amateur astronomy, on the other hand, is basically a religion for atheists. We keep at it for the same reasons the religious keep going back to church and re-reading the same unchanging book. It isn't about novelty. It is about ritual.

I used to be seriously into amateur astronomy as a kid in junior high. I got hooked in 1986 (I was 12, in 6th grade) with the return of Halley's comet, when our school's astronomy club held an open house. I later joined the club and was very active in it through the rest of school.

If you have the right sort of imagination and temperament, the first time you look through a telescope at an object that is not a star, and resolves from a pinprick to something else, can be something of a MAJOR mind-mess (I'd use a stronger term, but I suspect I'd get bleeped). Like a religious awakening. That's why Galileo's first glimpse of the true nature of the skies is practically a religious event in the history of science. If his experience were not reproducible, it would be rather like a private religious vision that converts people.

It is special even if you've seen pretty Voyager pictures and lots of Discovery TV.

Not everybody has this temperament. I've met people to whom I've shown Saturn's rings "live" as it were, and they are left cold. They might even say something like "I prefer the pictures in the book/TV, this is just a fuzzy ball.")

Why is it a mind-mess? The fact that something like Halley's comet or Saturn's rings or the moon's craters are actually just sitting out there in plain sight does a number on your brain. They are no longer abstractions. Not only are they real, they are more important than you. It is the biggest perspective shift you can experience. The night sky isn't a dome shaped background with pretty sprinkles, wrapped around earth. It is a vast void within which you don't even register as "mostly harmless" (Douglas Adams was being generous in even giving us those two words).

When I first saw Halley's comet, I vaguely recall that the general excited hubbub of the students around me immediately faded away for me, time sort of slowed down and even though I got only a few seconds at the telescope, it had an almost hallucinogenic effect on me.

Once I got into it, I'd stay up late night after night, learning the constellations, learning to spot the handful of nebulae and star clusters that you can see with the naked eye. On the astronomy club overnight camps, I was probably one of two or three kids for whom it was not primarily about using astronomy as an excuse for a sleepover. It was actually about star-gazing. Our school had an ancient, antique refractor telescope, nearly 100 years old (this was in India). Its brass polar mount had jammed at some North American latitude and could not be reset to our latitude (it had originally belonged to an American school). So it was hell finding stuff. It did not even have an achromatic lens.

Still, I'd stay up and get as much time with the telescope as I could. Possibly the most rewarding observing times were after 2 a.m., when the other kids had lost interest and had either fallen asleep or wandered off into the school grounds. 2 a.m. and later, the night air gets cold and still, atmospheric disturbances subside and you get the best seeing conditions. It also makes for the best solitary communion with the stars.

During the daytime, I'd devote hours to clipping out and organizing the "star of the week" column from the local newspaper, which was written by the director of the Birla Planetarium in Calcutta (I remember that the first writing prize I won was for an essay on space stations, submitted to one of their contests). I'd also spend hours at the library or at the astronomy club room, poring over the (reference only, no check out) copy of the Norton star atlas and old back issues of Sky and Telesecope. I'd keep renewing the few astronomy/astrophysics books available at the library.

Later (in 8th grade I think), I was probably one of the first kids in a generation at our school to get myself a telescope. There were very few (only two that I knew of) telescope manufacturers in India at the time (that may still be the case). Both were basically small businesses run by passionate individuals. I got one of these: http://www.sharpvisionindia.com/

It was very cheap and light, with mostly plastic parts. But as a reflecting Newtonian, it was still vastly better than the school's telescope. That telescope made me more of a night-owl and serious loner than any other force in my life. Even bookishness does not amplify introversion as much as amateur astronomy.

After I graduated, I donated my telescope to the school, and also helped them buy a new telescope, this time from the other, more expensive manufacturer in India that I knew of (Devdas telescoptics in Chennai, they don't seem to be online, at the time I found them through India's sole science magazine, which is now unfortunately defunct). This time, I happened to be in Chennai and I went out to the company to arrange the order. The entire "company" was basically the passion project of an elderly gentleman, Prof. Devdas, who made the telescopes himself. He'd had a life-long astronomy obsession. Something that is very hard to sustain in a country like India, where at the time, everything from skycharts to telescopes were thin on the ground.

I heard later that some American collector bought our old brass telescope as an antique, and paid quite a good sum for it.

I have mostly forgotten my astronomy knowledge these days. It was more a romantic passion than geeky curiosity back then, and now that the geeky curiosity has faded, only the romance remains. Like many others, when I was getting into it, obsessing over the technical details of telescopy, learning basic astrophysics and learning the name, location and biography of the brightest stars and other night sky objects were activities that were really about something else.

I had no other way to grapple with the profound, almost religious feeling that used to sweep over me each time I looked through a telescope, or simply up at a secret corner of the sky with the naked eye (slightly off to one side, to take advantage of peripheral vision sensitivity), where most people don't know to look. This is key by the way. The sense of being an initiate into esoteric knowledge, and an ability to see things others cannot, is key to the romantic appeal. It's like knowing a magic incantation that allows you to speak to dead people. At times, when I've shown someone how to carefully look in the right place to catch a wispy, ghostly glimpse of Andromeda, they are somewhat disturbed by the experience. It's like seeing a ghost in the room that's always been there, but wasn't visible before because you didn't know how to look.

My own obsessive memorization of star charts helped me understand why religious people feel like they have to memorize their texts chapter and verse. It's the only way to respond to urges that propel you to do something, but you don't know what exactly. So you memorize every intricate detail of the portal that leads to those strange, religious feelings.

It is this actual looking at the sky that is at the heart of amateur astronomy as a religion. It's the equivalent of prayer for atheists. Everything else is scaffolding: the equipment, the star charts, the showing off to other geeks with your superior navigation. The sooner you get past the equipment and geekiness, the sooner you realize that it is a romantic passion rather than an intellectual one. The heart of amateur astronomy is still naked-eye observation, with a star-chart burned in your brain, looking up at the sky in some lonely spot with perfectly clear skies. Not for stars, but for the meaning of your life. The religious seem to discover that it all makes sense, that they matter, and are the center of the universe, and find solace in that idea. Amateur astronomers seem to discover that it all does not make sense, that they don't matter, and are not the center of the universe. Curiously, they find just as much solace in that idea. There is a sense of relief.

Sadly, there is a point beyond which this living religion stuff has to end. Amateur astronomers (especially in the US) seem to like denying that theirs is primarily a romantic hobby. They like making up rationalizations and acting like they are building up towards the minor contributions that can be made to the professional game (variable star observations, comet-hunting... all mostly a case of the adults indulgently letting the kids pretend they are being helpful). I never bothered with this. To me amateur astronomy has no practical utility. If you want to actually contribute to science, you pretty much have to go pro.

Most serious astronomy requires cameras for long-term exposures, computer processing and so forth. Actually, most of the serious stuff isn't even at optical wavelengths. You do radio. A veil of science drops between you and your religion at the more advanced levels of astronomy. As a junior in college, in 1996, I was accepted into a summer school in astrophysics at the Inter University Center for Astronomy and Astrophysics (IUCAA), a leading astronomy center in India, next door to the Giant Meterwave Radio Telescope (GMRT, the largest in the world for meter-wave observation: http://en.wikipedia.org/wiki/Gia... ). It would have led on to IUCAA's PhD program. It was one of the most important career forks in the road for me. I decided not to go, and took a robotics internship at a defense lab in Bangalore instead. Part of it was that I'd realized by then that if I went professional, the romance would end up in the backseat.

When I came to the US in 1997, I finally had access to a rich amateur astronomy scene. I could afford fancy telescopes, join groups of well-equipped and knowledgeable enthusiasts, and so forth. But I never did get into it, partly because I never lived in parts of the US with lots of good seeing nights (either light pollution or winter gets in the way). But mostly it was because something turned me off about the American amateur astronomy scene. In a way, the scene has almost too many resources here. You can basically spend a whole lifetime pursuing the ever-more perfect equipment hoard, keep trying to compete with the professionals with their Hubbles, Arecibos and GMRTs, and so forth. Many American amateurs remind me more of photographers and gadget-philes. Not a bad thing, but it isn't about the romance of the night sky for them.

(I did peripherally retain an interest though; my PhD was about scheduling large interferometric space telescopes.)

So to answer your question, what is so amazing about the night sky? It is the Vatican City for atheist-romantics. It doesn't need to change. You don't need to see new things. Looking up at Saturn's rings every so often is like going to church. A visit from a comet is a festival to be celebrated.

Someday, if I end up living somewhere with many clear dark nights, I may buy a telescope again—a small one will do, no 18" Dobsonians for me—and get back in touch with the skies. I won't attempt to do "research" or contribute to the professional game. It'll just be a return to the romance. I probably won't join any local clubs either. Amateur astronomy works best as a private, mystical religion.