On a clear moonless night near the Rockies you can see the black outline of the mountains cutting into the slowly rotating bowl of stars. The sight can be mesmerizing - the sort of thing that can put you in danger of frostbite in the Winter. But a clear night sky was often different. On some nights the moon was wonderful lighting up the snow on the prairie, each year, on about August 12th the Perseid meteor shower gave an opportunity to spend the whole night outside on a lawn chair just watching, and every once and awhile the aurora would explode into view - sometimes so dramatically that you would wake the neighbors at 2am.
Even now with fantastic new imaging and results from professional astronomy, you can go out and wonder at the night sky. Jeri suggested mentioning the Kepler 22-b discovery. Around some types of stars there is a region where liquid water can exist - a requirement for life as we know it to evolve. This particular discovery is beyond the capabilities of amateurs, but there are many others that directly involve both communities. And such discoveries fire the imagination. As soon as I learned about the discovery I wondered exactly where the star was and if I could see it. It turns out to be an 11th magnitude star in Cygnus near its junction with Lyra and Draco. Something visible with a modest amateur telescope. If you go out and look you will probably be taken with thought that perhaps there is life there - and that the light you are seeing took about 600 years to reach your eyes.
The night sky is a powerful destination. There is a there there. (apologies to Gertrude Stein)
With the longer nights this is a time of year a lot of people think about getting a telescope for themselves or their children. Most people see a telescope in their local big box store or perhaps in a catalog and just get it. They, or worse their children, find these telescopes to be difficult to use and the optics are often terrible. The initial experience is awful and many of these scopes find themselves stored away and ultimately forgotten. It is the worst possible outcome - the cost per use is ridiculously high, a piece of unused hardware uses space and the owner is left with a bad first impression of astronomy. Experiences like this can kill rather than kindle curiosity.
Amateur astronomy involves a fair amount of learning. Perhaps the best path is a bit less steep, but one with high visual rewards and a low initial investment.
I'm going to recommend binoculars and a star chart program as the best "first telescope".
Binoculars have a lot of advantages. You can look at something in the sky and easily find it by just pointing your binoculars at it. They are very portable, the image is not inverted, they can be used for many other activities and a good enough pair is inexpensive.
To appreciate astronomy you really should learn the constellations. While it is possible to avoid that with some automated telescopes, there is a richness that comes with the familiarity of the night sky. Just going out and learning is good enough, but binoculars give you the excuse of searching for some specific objects and that rigor will help you learn more quickly. You'll quickly discover if this is something you love to do.
There are many things to look at that are wonderful with the modest 7 to 10 times magnification binoculars give. They are doing two things - magnifying the view a bit, but more importantly they are gathering more light that your unaided eyes can capture. You can see much fainter objects. A reasonable lens (lenses are called objectives) size if 50 millimeters in diameter. If you are over 35 your dilated pupil is about 5 mm in diameter - so these lenses would bring in about 100 times as much light.
The shorthand used for describing a binocular is to list its power and objective size. A 10x25 has ten power and 25mm objectives. The best sizes for the beginning amateur are probably 7x50 to 10x50. These are easy to hold and point at the sky for extended periods and bring in enough light to see some of the best common objects.
Go to a sporting goods store or, if you have one, a store that specializes in astronomy and try several out. If you have astigmatism you'll need to wear your glasses. You'll want to make sure they are well-made and comfortable, provide a clear image, have coated optics, have an exit pupil that matches your pupil size.1 You should be able to find something good enough for about $100.
The next thing you need is a star chart. A year ago I would recommend a good star atlas, but developments in smartphone apps have completely changed the game. I've used eight night sky apps. The standout is Sky Safari 3 by Southern Stars for the iPhone and iPad. Either device is good - the iPhone is highly portable, but the iPad gives you much more area to hold up and "match" to the sky. These are so good that I would almost recommend getting an iPad before getting the binoculars - you can find a good used original iPad for about $200 these days. Sky Safari is on sale for the next few days in three versions. If you think you are going to be interested beyond looking at the sky a few times I would go with the Plus version which shows satellites and has a much deeper catalog. The Pro version is deeper still and both of these versions can interact with many of the current "goto" class of amateur telescopes. Star charts and programs can be studied indoors when you can't be outside observing and good ones encourage study. I grew up with the Norton's Star Atlas - a wonderful resource that I still recommend - but Sky Safari is much deeper and interactive. If you don't have an iPad, buy one and get the program.
Armed with Sky Safari and a good pair of binoculars, you'll need something to look at. Your library will have a lot of beginner's books on astronomy that will offer suggestions. Binocular Highlights by Gary Seronik is a good resource that is well matched to the beginner. Sky and Telescope magazine has a nice monthly column with objects in the current night sky that makes the magazine worth the subscription price, although most public and school libraries carry it. S&T has articles for the absolute beginner as well as some of the most sophisticated amateur observers and telescope makers. Astronomy is a field that sometimes mixes amateurs and professionals and the magazine has great columns that detail what is going on in professional astronomy and astrophysics at the level one expects in Scientific American. A fantastic resource - I have had a subscription since I was twelve.
If you get to the point where you realize you love this and are beginning to learn the sky it is time to think about a telescope. These cost anywhere from a few hundred dollars and up, but a great first telescope is a Dobsonian. They have a very simple design that assumes you just want to point the 'scope at an object and gather the most amount of light for the money you have spent. They don't compensate for the Earth's rotation and are useless for astrophotography, but they are inexpensive and can provide wonderful view of the night sky. Chances that you will be frustrated are low assuming you have gained enough experience learning the sky first.
A good Dobsonian with an eight inch mirror can be had for $300 to $400. Add a few hundred dollars and some are fitted with digital encoders that report the orientation of the telescope to a small computer. When you first set up the telescope you are asked to point it at a few known bright stars and then the computer calculates the telescope's orientation relative to the sky and can give you directions to find thousands of other objects in its catalog.2 Using this star finding scheme is an easy and natural way to spend hours of time - I've gone from dusk to dawn just having fun. You'll want to get the largest you can afford that can be easily moved to a dark enough observing area and that you can comfortably use.
This is a good time to find a mentor. Astronomy clubs and societies often hold star parties in dark areas and a few have dedicated observatories or places out in the middle of nowhere. You'll find many amateurs to be passionate and helpful. You may want to do this before getting a Dobsonian, but it would certainly do it shortly afterwards. You'll zoom up the learning curve.
Moving to a telescope with a mount that compensates for the Earth's rotation adds cost. The mount quickly becomes a critical component. Setting up the mount can be complex - a tricky enough procedure that many beginners can become discouraged so it is probably best to move to this class once you have some experience under your belt - or at least the help of a good mentor.
Most people go for six or eight inch compound optics telescope - Schmidt-Cassegrain or Maksutov-Cassegrain designs being the most common. These folded optical paths reduce the length of the telescope making them relatively compact and easy to transport. The price per inch of aperture is greater than a Dobsonian with an entry level eight inch telescope and mount staring at about $1000 with a nicer ''scopes going for about $2000. It is very easy to move well beyond that with much better mounts and optics, but it is like high fidelity - there is a point of diminishing returns.
At this point serious amateurs tend to specialize and specialized needs can dictate high quality refracting telescopes or specialized reflectors like Ritchey-Chrétien optical designs. It has been observed that serious hobbyists often spend as much on their hobby as they do on a car. Dedicated observatories with $50k telescopes on $20k mounts are not unheard of and specialized cameras and accessories can run the costs much higher. Locations in very dark regions of New Mexico and Arizona are desirable, although getting there can be challenging. A few communities devoted exclusively to advanced amateur astronomers have appeared along with some focused bed and breakfasts and companies that rent out remote telescopes by the hour.
I've used some of the exotic equipment, but don't personally own any "big glass." I love getting out to these dark locations, but just being under the stars and gazing up often is enough. I will take an SLR or DSLR and put it on a mount that compensates for the Earth's rotation so I can take a time exposure. You get the sense of what the sky would look like if your eyes were a hundred or a thousand times more sensitive and you can bring out the colors. I also like observing the Sun - something that works in heavily light polluted regions. Traveling to solar eclipses and to places where there are likely to be auroral displays is also a great way to spend time. Everyone develops some paths they love and these can change over time as you gain experience.
Sometimes people ask about activities for kids who are interested in science. I'm not a fan of heavily scheduling kids with activities. Instead I believe in a lot of free time and "free range" activities so they can explore and probe on their own. Amateur science can teach you how to observe nature and ask good questions. When I get involved in college admissions I tend to look for those who show real passion for such things - those are the ones who ultimately succeed in the sciences.3 These skills can be very useful for some types of work and people who have them are sadly too rare. Microscopes, telescopes, a chemistry set, a rock hammer and other devices that extend our senses and, when combined with curiosity, can lead to much greater things. I count myself as lucky that I had dark skies and the gift of unscheduled time along with a very modest amount of money to pursue a few passions.
1 There are a lot of specialized issues. Eye relief is the distance from the eyepiece to where you can see the full image. Many binoculars are 10mm or less. If you wear glasses you'll need more - maybe as much as 15mm or more. The diameter of your dilated pupil decreases with age. When you are a teen it is as large as 7mm, but drops to about 5 mm when you get to be 35 or so. The size of the objective divided by the power gives the size of the focused image that can be delivered to the eye. So a 7x50 would give roughly a 7mm image and a 10x50 a 5mm. The first would be better for teenage eyes and the second for older eyes.
Just trying the binoculars gives a good sense. If you are using mail order shop with a company that specializes in amateur astronomy. Celestron, Meade and Orion are good places to start that offer a lot of beginner's gear. Ask for suggestions and tell them about your eyes.
I use Canon 15x50 image stabilized binoculars. They are extremely spendy and overkill for the beginner who doesn't know if this is something they will come to love. I them constantly for many purposes and they've given me a decade of service (so far) without any problems, so I'm happy. Their big advantage is active image stabilization which allows you to comfortably use a slightly higher power than is possible with normal binoculars. I would recommend them, but only if you know they are something you are going to use heavily.
2 Normally I don't like giving specific recommendations without knowing more about someone's specific requirements, but Orion's IntelliScope Dobsonians are great for beginners. The eight inch is about $550, can fit in most car trunks and breaks into two pieces that are both under 21 pounds. Anyone over about 5'2 should be able to use it in any orientation without a stool. Their 12" gives more spectacular views, but probably requires a large truck or an SUV or pickup. The optical tube weighs 50 pounds and may be too much for some people. Going a bit larger (14" or 16" in many designs depending on how fast the optics are) quickly takes you to the point where only Colleen sized people can get away with using it without a stool - I've used one that was a bit too tall for me and found you can easily get into uncomfortable positions. Some amateur Dobsonians can be huge. I have used a 36" homemade monster in New Mexico that had a 16 foot optical tube. You needed a tall ladder to observe and I saw people "hop" the ladders as they went from object to object. Not exactly safe, but the view of the Andromeda galaxy was astonishing. The warning for any telescope is to spend time worrying about how you can move it along with the ergonomics of using it. Using someone else's at a star party can be very useful.
3 There is a lot of real science you can easily investigate on your own. Figuring out ow to confirm old results is a great learning experience that get you thinking more deeply. Measuring the speed of light by observing the moon's around another planet should be within the capabilities of a curious 8th grader. Your mind goes beyond that as you use your own observations to discover. While most of the discoveries are known there is a thrill of stumbling onto something and creating dots of understanding in your mind that can later be linked. I was about 14 when I realized the latest sunrise and earliest sunset did not occur on the Winter Solstice in Montana. That led to puzzling out why and I ended up teaching myself spherical trigonometry in the process. It was also about the first time I realized I had thought deeply about something that most adults are not aware of...
People sometimes ask how accurate the television show Big Bang Theory is:-) While they clearly have a science advisor to get the terminology correct, it completely misses the sociology of science - at least the sciences I'm familiar with...