Amateur astronomy

Amateur astronomy, a subset of astronomy, is a hobby whose participants enjoy studying celestial objects. It is usually associated with viewing the night sky when most celestial objects and events are visible, but sometimes amateur astronomers also operate during the day for events such as sunspots and solar eclipses. Amateur astronomers often look at the sky using nothing more than their eyes, but common tools for amateur astronomy include portable telescopes and binoculars.

People have studied the sky throughout history in an amateur framework, without any formal method of funding. It is only within about the past century, however, that amateur astronomy has become an activity clearly distinguished from professional astronomy, and other related activities.

Amateur astronomy objectives

Collectively, amateur astronomers observe a variety of celestial objects and phenomena. Common targets of amateur astronomers include the Moon, planets, stars, comets, meteor showers, and a variety of deep sky objects such as star clusters, galaxies, and nebulae. Many amateurs like to specialise in observing particular objects, types of objects, or types of events which interest them. One branch of amateur astronomy, amateur astrophotography, involves the taking of photos of the night sky. Astrophotography has become more popular for amateurs in recent times, as relatively sophisticated equipment such as high quality CCD cameras has become more affordable.

Most amateurs work at visible wavelengths, but a small minority experiment with wavelengths outside the visible spectrum. The pioneer of amateur radio astronomy was Karl Jansky who started observing the sky at radio wavelengths in the 1930s, and interest has increased over time. Non-visual amateur astronomy includes the use of infrared filters on conventional telescopes, and also the use of radio telescopes. Some amateur astronomers use home-made radio telescopes, while others use radio telescopes that were originally built for astronomy research but have since been made available for use by amateurs. The One-Mile Telescope is one such example.

Common tools

Amateur astronomers use a range of instruments to study the sky, depending on a combination of their interests and resources. Methods include simply looking at the night sky with the naked eye, using binoculars, using a variety of telescopes of varying power and quality, as well as additional sophisticated equipment, such as cameras, to study light from the sky in both the visual and non-visual spectrum. Commercial telescopes are available and used, but in some places it is also common for amateur astronomers to build (or commission the building of) their own custom telescope. Some people even focus on amateur telescope making as their primary interest within the hobby of amateur astronomy.

Although specialised and experienced amateur astronomers tend to acquire more specialised and more powerful equipment, it's not unusual relatively simple equipment to be preferred for certain tasks. Binoculars, for instance, although generally lower power than the majority of telescopes, also tend to provide a wider field of view, which is preferable for looking at some objects in the night sky.

Amateur astronomers also use maps that, depending on experience and intentions, may range from simple planispheres through to detailed maps of very specific areas of the night sky. A range of astronomy software is available and used by amateur astronomers, including software that generates maps of the sky, software to assist with astrophotography, and software to perform various calculations pertaining to astronomical phenomena.

Amateur astronomers often like to keep records of their observations, which may take the form of an observing log. Observing logs typically record details about which objects were observed and when, as well as describing the details that were seen. Sketching is sometimes used within logs, and photographic records of observations have also been used in recent times.

Common techniques

Many methods are used in amateur astronomy to locate items in the sky, but most are variations of a few specific techniques.

Star hopping is a method often used by amateur astronomers with low-tech equipment such as binoculars or a manually driven telescope. It involves the use of maps (or memory) to locate known landmark stars, and "hopping" between them. Because of its simplicity, star hopping is a very common method for finding bright and commonly known objects in the sky. Astronomers with some experience can also use the technique to find fainter and more difficult objects.

More advanced methods of locating objects in the sky include setting circles, which assist with pointing telescopes to positions in the sky that are known to contain objects of interest, and GOTO telescopes, which are fully automated telescopes that are capable of locating objects on demand (having first been calibrated).

Setting circles are angular measurment scales that can be placed on the two main rotation axes of some telescopes. By knowing the coordinates of an object (usually given as equatorial coordinates), the telescope user can use the setting circles to align the telescope in the appropriate direction before looking through its eyepiece. In one variation of setting circles, known as digital setting circles, the current pointing coordinates of the telescope are displayed to the user digitally.

GOTO telescopes have become more popular in recent times as technology has improved and prices have reduced. With these computer-driven telescopes, the user typically enters the name of the item of interest and the mechanics of the telescope point the telescope towards that item automatically. They have several notable advantages for amateur astronomers intent on research. For example, GOTO telescopes tend to be faster for locating items of interest than star hopping, allowing more time for studying of the object. On the other hand, some people have argued that the money spent on complex electronics and mounting systems could be better spent on higher quality optics.

Arguably, the increased affordability of GOTO telescopes has also resulted in a new type of beginning amateur astronomer, because GOTO telescopes offer a form of instant gratification, sometimes allowing difficult objects to be found quickly without requiring the experience of learning to find them. There is some debate, usually light-hearted, within the amateur astronomy community about which method is superior. Some astronomers argue that beginning with the lower end of technology and using star hopping techniques is an excellent method of learning the sky, and that a good knowledge of the night sky can be advantageous for people who prefer simpler equipment with less calibration and setup time, and is therefore more versatile. GOTO telescopes, on the other hand, do make the hobby more accessible. They also tend to be preferred by people who are more serious about studying objects, because less time and effort is required for finding objects when well prepared.

Scientific research

Scientific research is most often not the main goal for many amateur astronomers, unlike professional astronomy. Work of scientific merit is possible, however, and many amateurs successfully contribute to the knowledge base of professional astronomers. Astronomy is sometimes promoted as one of the few remaining sciences for which amateurs can still contribute useful data. To recognise this, the Astronomical Society of the Pacific annually gives Amateur Achievement Awards for significant contributions to astronomy by amateurs.

The majority of scientific contributions by amateur astronomers are in the area of data collection. In particular, this applies where large numbers of amateur astronomers with small telescopes are more effective than the relatively small number of large telescopes that are available to professional astronomers. Several organisations, such as the Center for Backyard Astrophysics [1], exist to help coordinate these contributions.

Amateur astronomers often contribute toward activities such as monitoring the changes in brightness of variable stars, helping to track asteroids, and observing occultations to determine both the shape of asteroids and the shape of the terrain on the apparent edge of the Moon as seen from Earth. With more advanced equipment, but still cheap in comparison to professional setups, amateur astronomers can measure the light spectrum emitted from astronomical objects, which can yield high-quality scientific data if the measurements are performed with due care. A relatively recent for amateur astronomers is searching for overlooked phenomena (e.g. Kreutz Sungrazers) in the vast libraries of digital images and other data captured by Earth and space based observatories, much of which is available over the Internet.

In the past and present, amateur astronomers have played a major role in discovering new comets. Recently however, funding of projects such as the Lincoln Near-Earth Asteroid Research and Near Earth Asteroid Tracking projects has meant that most comets are now discovered by automated systems, long before it is possible for amateurs to see them.

Societies

There are a large number of amateur astronomical societies around the world that serve as a meeting point for those interested in amateur astronomy, whether they be people who are actively interested in observing or "armchair astronomers" who may be simply interested in the topic. Societies range widely in their goals, depending on a variety of factors such as geographic spread, local circumstances, size and membership. For instance, a local society in the middle of a large city may have regular meetings with speakers, focusing less on observing the night sky if the membership is less able to observe due to factors such as light pollution.

It is common for local societies to hold regular meetings, which may include activities such as star parties or presentations. Societies are also a meeting point for people with particular interests, such as amateur telescope making.

Famous Amateur Astromoners

William D. Ferris discovered several comets and was the first to observe near-Earth objects. Robert Fried founded the Braeside Observatory in Flagstaff, Arizona, in the 1960s. David H. Levy co-discovered Comet Shoemaker-Levy 9. Leslie Peltier was a prolific discoverer of comets and well-known observer of variable stars. Isaac Roberts was the first to apply photography to astronomy. Leon Stuart photographed a Lunar flare on November 15, 1953. Amateur Thomas Bopp shared the discovery of comet Hale-Bopp in 1997 with unemployed PhD physicist Alan Hale.

References

"American Association of Variable Star Observers". AAVSO. Retrieved 2006-08-24.
"The American Meteor Society". Retrieved 2006-08-24.
"The International Occultation Timing Association". Retrieved 2006-08-24.
"Edgar Wilson Award". Harvard-Smithsonian Center for Astrophysics. Retrieved 2006-08-24.

External links

The Astronomical League - the world's largest society of amateur astronomers
Society for Popular Astronomy - the UK's biggest society for amateur astronomers
Society of Amateur Radio Astronomers
Amateur Search for Extraterrestrial Intelligence

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Amateur astronomy