THE dark skies above the high deserts of Arizona are among the best an amateur astronomer can ask for. Here, numerous hobbyists scan the skies for comets, near-Earth asteroids and supernovae.
Only a handful of years ago, this task would have required many hours of preparation setting up a telescope, calibrating the precision mechanism for pointing it, finding the area of sky to study, and then photographing it 鈥� itself a difficult task with a film-based camera. At best, the images would have taken hours to develop, and then would begin the tiring, time-consuming task of comparing by eye the images with previous ones, looking for any changes.
Automated telescopes, digital cameras and powerful image-processing programs are changing all that. After a brief set-up, an automated telescope will point at an area of sky, a digital camera will photograph it, and a computer will compare the image with previous ones and move on to the next shot, all with little if any human input. One serious amateur in Arizona, for example, has an array of four large telescopes that he pre-programs to photograph hundreds of target objects in a night. While he goes about his business eating dinner or watching TV, his equipment has helped him become one of the world鈥檚 leading discoverers of minor planets and supernovas.
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This kind of control system, which can challenge professional astronomers, costs upwards of $10,000 and the telescopes themselves cost thousands more. But cheaper versions are starting to filter down to the masses. In 1999, two US manufacturers, Meade and Celestron, launched automated 鈥済o-to鈥� telescopes for under $1000 that can find planets, nebulae and galaxies at the press of a button. Simple designs and inexpensive manufacturing have allowed prices for the most basic models to drop to as little as $200 in the US and 拢250 in the UK.
The result has been a huge rise in sales and increases of tenfold or more in attendance at some star parties, where people gather to look through a variety of telescopes brought by those who attend. Terrence Dickinson, an author of introductory books on amateur astronomy, says the audience at his astronomy lectures have become far more diverse. Ten years go, 85 per cent were men, most of them in their teens and 20s. Today, his audiences span every age group, and men no longer outnumber women. A rapidly increasing segment is recently retired people, who might have been daunted by the demands of the old do-it-yourself approach.
The latest trend, and the biggest change in the landscape at star parties, is the prevalence of laptops running one of many astronomy programs now available. These range from home planetarium programs such Starry Night, The Sky and RedShift, with slick graphics, vast databases and links to the internet, to basic star charts such as the 2Sky program for hand-held computers running the Palm operating system. Some of these programs can control an automated telescope directly and even record and process images taken with a digital camera fitted to the instrument.
For experienced observers, the automated telescopes, whether controlled by a built-in go-to system or a connected laptop or Palm device, speed up the task of locating objects in the night sky, leaving them more time for observation. That, along with the ever-increasing power and stability of electronic imaging devices, is why experienced amateurs have become increasingly vital contributors to projects such as the search and tracking of near-Earth asteroids.
And processing the images once they鈥檝e been captured is becoming easier too. One way to capture more detail is to increase the length of an exposure, but this requires the telescope to track an object precisely. But a popular option is to take several short exposures and stack them on top of each other using one of the many image processing programs now available.
Together these developments are closing the gap between pros and amateurs. Which is why making a contribution doesn鈥檛 mean being based in Arizona.
Chatted to your telescope lately?
The ads proclaim it loudly: the latest entry-level telescopes are so simple that a novice can pull one from the box and in a matter of a minutes be set up and ready to observe stars, planets, nebulae and galaxies, even if he or she wouldn鈥檛 know one from the other.
It may not be quite that simple, but manufacturers are planning improvements to 鈥済o-to鈥� telescopes that will make the setup even easier. For example, setting up normally requires the user to enter the location, elevation and time, and to know which way is north. But if somebody knocks the telescope, the whole set up process has to be repeated. American manufacturers Meade and Celestron are already offering instruments with built-in GPS satellite positioning receivers that automatically provide location information.
Another trend is to use voice-recognition software to control the device and to build in speech-synthesis programs to read out information from the computer. Amateurs have been improvising such systems for several years, mating existing speech-recognition programs with go-to telescopes that can be pointed through simple commands, and adapting programs originally designed for visually impaired people that can read text aloud 鈥� for example, to provide information about the objects being viewed. That helps beginners understand the skies and helps experienced users by protecting their night vision from the relatively bright lights of computer displays. Meade has introduced models with speech capability, and Celestron is working on one with voice recognition.
