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Amateur Astronomy Under ideal conditions, there are about 1,500 stars visible to the naked eye. With a good pair of binoculars or a telescope, the number of celestial objects you can view jumps, well, astronomically. Perhaps more than any other science, astronomy has always attracted a large number of knowledgeable, dedicated amateurs. If you are interested in serious astronomy, here is a collection of resources I know you will enjoy. Find out about news, sky events, clubs and organizations, do-it-yourself projects, hints on what to look for, telescope information, observatories, planetariums, and much more. Remember, when it comes to astronomy, anyone can be a star. Web:
Astronomy Catalogs When astronomers are interested in observing a particular heavenly body, how do you think they find what they are looking for? They use special catalogs, of which there are several thousand. If you are a professional astronomer -- or an amateur with some technical knowledge -- you'll find it extremely useful to search these catalogs online. (Hint: If you can't find the heavenly body you want in one of these catalogs, try one from Victoria's Secret.) Web:
Astronomy History The study of astronomy is as old as the study of science. Aristarchus of Samos (310-230 B.C.), an early Greek astronomer, suggested that the Earth rotated on its axis and that the planets rotate around the sun in circular orbits. (Actually, the orbits are elliptical.) He also used his own observations along with his knowledge of geometry to determine the relative sizes of the Earth, the moon and the sun, and the distances between them. Personally, I have always been fascinated by man's quest to understand the cosmos. Yes, there were a few false starts (like the Dark Ages and the sixteenth century Catholic Church), but by and large, mankind has made enormous progress in understanding the nature of our universe. Web:
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Astronomy News If you are a professional or amateur astronomer, there is no shortage of news to capture your interest. Information about current launches, new data and discoveries is available on the Net. There are also a lot of informative articles to help you keep abreast of what is new and exciting. These resources are great places to visit whenever you get a few moments. Web:
Astronomy Resources Although we live on planet Earth, our eyes have always turned upward to the sun, the moon, the stars and the planets. Astronomy is one of the oldest sciences, having evolved from the observation of heavenly bodies to the general study of matter and energy in the universe. You'll love spending time with these astronomy resources, reading about comets, meteors, asteroids, planets and the solar system. You'll also find information about space exploration, astronomy magazines, and the history of astronomy. I especially enjoy looking at the wonderful astronomical images. Hint for Windows users: When you find an image you like, you can set it as the background for your desktop. (1) Use your browser to find a particularly cool astronomical image. (2) With your mouse, right-click on the image. You will see a list of choices. (3) Choose "Set as wallpaper". The background on your desktop is now the image you selected. (If you want to reset the background to the way it was, right-click on the desktop and choose "Properties". Then click on the "Background" tab.) Web:
Astronomy Software The days have long passed since an astronomer could operate with a telescope and a notebook. Modern astronomy requires a lot of computers and a lot of computer programs. Here is a comprehensive collection of links to many different sites containing astronomy software. Whatever you need -- everything under (and over) the sun -- if it's available on the Net, you will probably find it here. Web:
Astronomy Talk and General Discussion Would you like to talk with people who really do understand black holes? Join the astronomers on Usenet and discuss all aspects of astronomy and astrophysics: stars, planets, telescopes, cosmology, space exploration, and so on. The sci.astro.amateur group is specifically for amateur astronomers. Usenet:
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Astrophysics Data System The Astrophysics Data System allows access to hundreds of thousands of abstracts (astronomy and astrophysics, space instrumentation, physics and geophysics, and more), as well as access or links to archives and catalogs of astronomical data, including data collected by NASA space missions. Web: Comets Imagine you are walking down the street, and you see a small block of ice and slush with a rock in the middle. So what? But take that same small block of ice and slush with a rock in the middle and send it in an eccentric, elliptical orbit around the sun, where the solar wind can cause tiny particles to stream out from the block forming a tail over a million kilometers long, a tail that is visible from Earth. You now have a comet. Most comets are not visible to the naked eye, but from time to time, one does arise that is easy to see, and the effect it has on humanity is stupendous. Comets are common, however, and with a telescope, there are always a few that are visible. Although some comets follow periodic schedules, returning to Earth again and again, many comets are new and unexpected and, indeed, are discovered by amateurs. Web:
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Constellations Look up into the night sky when the stars are visible, and you will begin to see patterns. Since ancient times, men have identified such patterns, called constellations, and given them names. The oldest references to constellations are from the ancient Greeks, although those constellations probably originated even earlier, among the Sumerians and Babylonians. The modern system of constellations is based on the Greek ones, but has been codified and expanded to cover the entire sky (including the southern areas that were not visible to the Greeks). Today, we recognize 88 different constellations. As you look at the stars, remember that the constellations are artificial constructions made up by people. Only the stars are real. Web:
Dark Sky Stargazing One time I was camping by myself in a national park east of San Diego, and I ran into a couple of teenagers who had never been out of the city. While talking to them, I found out they had never seen the Milky Way (the long, extended clumping of stars that is actually part of our galaxy), because the lights of the city were so bright as to obscure most of the stars. It wasn't until the boys had finally ventured to the countryside that they were able to see this remarkable phenomenon. Astronomers (professional and amateur) have the same problem. Cities create so much light pollution as to seriously impact astronomical observation. To look at the heavens, you need a dark sky, and these Web sites can help you find it. Web:
Eclipses An eclipse occurs when one heavenly body casts a shadow on another. To Earthbound observers (you and me), the most important eclipses are those in which the moon comes between us and the sun (a solar eclipse), and those in which the Earth comes between the moon and the sun (a lunar eclipse). The most spectacular eclipses are total solar eclipses, in which the moon, for a short time, will almost completely block the light from the sun. In other words, the moon casts its shadow on the Earth. If you happen to be in this shadow, you will see the awesome sight of the disc of the sun slowly being covered and then, a few minutes later, regaining its original appearance. These Web sites contain pictures of eclipses and information about future eclipses. Web:
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Extrasolar Planets Are there planets outside our own solar system that are capable of supporting life? For a long time, astronomers searched for such extrasolar planets (sometimes called "exoplanets"), but with no success. The difficulty is that, at such great distances, anything as small as a planet cannot be seen with a telescope. Instead, astronomers examine one star at a time, looking for tiny perturbations in the star's movements, perturbations that can only be caused by a planet-like object orbiting the star. In October 1995, astronomers at Geneva University found the first such planet and, since then, a growing number of new planets have been found. Compared to the planets in our own solar system, most of the extrasolar planets are significantly different, and it is very unlikely that any of them could support life. However, what we do know is that planets are common throughout the galaxy. Perhaps one day, we will find an extrasolar planet that is similar to our own. Web:
Observatories and Telescopes One of the things I like best about the Net is that it provides a place for information that literally did not exist before there was an international computer network. For example, say that you want to look for a particular observatory or telescope. Before the Net existed, where could you even look for an up-to-date master list? Now it's easy to find what you want. Just check these sites and find links to hundreds of observatories and telescopes all over the globe. Web:
Peculiar Galaxies In the 1960s, the astronomer Halton C. Arp collected images of 338 "peculiar galaxies", that is, galaxies with unusual or abnormal shapes. Arp published a book called the Atlas of Peculiar Galaxies, which has become the standard reference work for what many people now refer to as "Arp objects". Arp's work contributed greatly to the study of the nature of galaxies, and today there are Arp enthusiasts around the world who photograph as many Arp objects as they can. Start here if you would like to learn more about these intriguing galactic phenomena (and look at some cool pictures). Web:
Planetary Nebulae Within a star there are two great forces balancing one another: the force of gravity (pulling inwards), and the force of heat from the core, created by the fusion of hydrogen to helium (pushing outwards). After a hundred million to ten billion years, depending on the size of the star, the hydrogen is depleted. When this happens, the fusion stops and gravity causes the star to collapse. New reactions begin to take place in the core, resulting in the liberation of a large amount of energy. This energy causes the star to expand, resulting in the formation of a red giant. Eventually, the core completely runs out of fuel and gravity causes the star to collapse. For almost all stars, this leads to the formation of a white dwarf. (With the largest 5 percent of stars, a huge explosion called a supernova occurs instead.) Just before the formation of a white dwarf, large amounts of gaseous matter are thrown off by the dying star, forming a huge gaseous shell around the white dwarf. This shell is called a planetary nebula. (The name comes from a mistake early astronomers made, when they saw such formations and thought they resembled the planet Uranus.) Within the grand scheme of the galaxy, planetary nebulae are short-lived, lasting only about 25,000 years. There are thought to be about 10,000 such bodies in our galaxy. Web:
Radio Astronomy When you and I look at the sky, we see visible light, which represents only a tiny portion of the electromagnetic spectrum. However, celestial objects emit radiation in all parts of the spectrum, and radio telescopes, which are sensitive to radio waves, can detect a wealth of emissions that would normally pass us by. The fact that celestial bodies emit detectable radio waves was discovered by accident in 1931 by Karl Jansky, a researcher at Bell Labs. Jansky announced his discovery in 1933, which inspired a young radio engineer named Grote Reber to build the first radio telescope. In 1940, Reber published an article called "Cosmic Static" in the Astrophysical Journal, an article that ushered in the age of radio astronomy. One of the most important characteristics of radio waves is that they pass through interstellar dust clouds that block visible light. Thus, radio telescopes allow us to explore parts of the universe that would otherwise be inaccessible. Web:
Robotic Telescopes Professional caliber telescopes are wonderful tools, but access is limited and, for an amateur astronomer, almost impossible to obtain. There are, however, a few such telescopes that can be used by anyone. You can send a request to have the telescope look at a particular position in the sky. The results will be sent to you either as a picture or raw data in FITS (Flexible Image Transport System) format. These resources are suitable for college-level students, researchers and knowledgeable amateurs. Web:
SkyView SkyView is a sophisticated tool that allows you to look at various parts of the sky in different wavelengths. However, SkyView does not show you real images: rather, it creates the images you want, based on your specifications, by using an extensive database of astronomical observations. In other words, SkyView is a virtual telescope. The system is set up with various interfaces, for both professional astronomers and amateurs. Web: Space Calendar If you think it's disastrous when you lose your datebook, how do you think NASA feels? When you are shooting live human beings into space at high speeds, it's important to keep your scheduling straight. Check here if you want to keep up on what's happening in the cosmos. Web:
Telescopes It's tempting to rush out and buy a telescope, but don't. Take time, before you buy, to learn what you are doing. I once bought a high-quality telescope, and I sure was glad I did some research before I made my selection. Here are some resources to help you, including a FAQ (frequently asked question list) about buying and using a telescope. Harley's Rules for Buying a Telescope: (1) When you buy a telescope, you get what you pay for. (2) The one you need costs more than you can afford. Web:
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