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.

Amateur astronomy and scientific research

Unlike professional astronomy, scientific research is most often not the main goal for many amateur astronomers. Work of scientific merit is certainly possible, however, and many amateurs successfully contribute to the knowledge base of professional astronomers. Astronomy is often promoted as one of the few remaining sciences for which amateurs can still contribute useful data.

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 ^*, 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 for amateur astronomy

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. Other activities could include amateur telescope making, which was pioneered in America by Russell W. Porter, who later played a major role in design and construction of the Hale Telescope.

Approaches to using amateur telescopes

Amateur telescopes come in many shapes and sizes, both commercial and home-built. The preferences of people who use them often differ.

Star hopping

Some amateur astronomers prefer to learn the sky as accurately as they can, using maps to find their way between the stars. In this case a common approach is to use binoculars or a manually driven telescope, combined with star maps, to locate items of interest in the sky. The normal technique for doing this, by locating landmark stars and "hopping" between them, is called star hopping.

GOTO telescopes

More recently as technology has improved and prices have come down, automated "GOTO" telescopes have also become a popular choice. With these computer-driven telescopes, the user typically enters the name of the item they wish to look at, and the telescope finds it in the sky automatically with comparatively little further effort required by the user.

The main advantage of a "GOTO" telescope for an experienced amateur astronomer is the reduction of "wasted" time that may have otherwise been used in trying to find a particular object. This time can therefore be used more effectively for studying the object.

Comparing methodologies

There is significant (though usually light-hearted) debate within the hobby about which method is better. Promoters of the star hopping approach for finding items in the sky usually argue that they know the sky much better as a result. The manual method also tends to require simpler equipment with less calibration and setup time, and is therefore more versatile. Promoters of "GOTO" telescopes often argue that they are more interested in studying objects, and the reward of finding them or learning exactly where they are is not as important to them.

It may also be argued that the money spent on complex electronics and mounting systems might be better spent on higher quality optics.

Other wavelengths

Most amateurs work at visible wavelengths, but a small minority experiment with wavelengths outside the visible spectrum. This includes the use of infrared filters on conventional telescopes, and also the use of radio telescopes. The pioneer of amateur radio astronomy was Karl Jansky who started observing the sky at radio wavelengths in the 1930s. A number of amateur astronomers use either homemade telescopes or use radio telescopes which were originally built for astronomy research but which are now available to amateurs (e.g. the One-Mile Telescope).

Additional tools and activities

In addition to optical equipment, amateur astronomers use a variety of other tools such as celestial maps, and specialised computer software. There is a range of astronomy software available, from planetarium programs that simulate the sky to programs used to do various kinds of calculations pertaining to astronomical phenomena.

Some amateur astronomers also keep a record of their observations. This can take the form of an observing log, in which they record details about which objects were observed and describing the details that were seen. Astrophotography and sketching are also popularly used to record observations.

Beginning in amateur astronomy

There are a many ways for people to become involved in amateur astronomy and study the night sky. One option is to join a local astronomical society, the members of which will often be very happy to help a newcomer take a more active part. Some people also prefer to simply teach themselves, in which case there are likely to be a large amount of books in the local library.

Common objects that are observed early are the Moon and planets. Another thing that most newcomers to amateur astronomy become acquainted with are the more prominent constellations in the night sky. When reading maps and interpreting instructions for future star hopping, constellations are good starting points for identifying locations in the night sky. They are frequently referred to by amateur astronomers when discussing the location of items of interest when looked at with binoculars and telescopes.

Beginning with a GOTO telescope

A relatively new type of beginning amateur astronomer, brought about by the increased affordability of powerful "GOTO" telescopes, is one who begins with such a telescope. It is possible for an inexperienced person to immediately look at a large amount of deep sky objects in the night sky without necessarily having any prior experience or training.

There is currently some debate among amateur astronomers about the merits of this approach to becoming involved in the hobby, and the effects that low-priced GOTO telescopes may be having. Amateur astronomy is exposed to more people, as an individual is less likely to be discouraged by the need to learn how to locate objects in the night sky before being able to see them. Some are concerned, however, that newcomers may become bored very quickly. A GOTO telescope does not distinguish between objects that are easy and hard to see, and newcomers may therefore begin with objects that require large amounts of experience or understanding to properly appreciate.

Becoming acquainted with the night sky

Most tutors agree that it is very important to know one's way around the sky by means of the constellations. This ability forms a platform from which deeper explorations of the sky are then possible.

A planisphere can be used to find and identify the constellations. These devises show the location of the constellations for any time of the night or time of the year. An observer will also need a red flashlight to read star charts or the planisphere. Use of a red light helps preserve the dark adaptation of the eyes.

Having learned the main constellations, a beginner may want to extend their hobby and buy a pair of binoculars or a telescope.

Using binoculars

With binoculars it is possible to see many deep sky objects (DSOs). Holding the binoculars can produce a shaky image. One way to improve the view is with the aid of a sturdy tripod mount to steady the view through the binoculars. Binoculars are still limited in range, although most of the Messier catalogue should be visible, as well as a great many NGC's, especially near the Milky Way. An advantage of binoculars is that they allow more complete wide field views of the larger open clusters such as the Pleiades, the Hyades, the Coma Berenices cluster and Praesepe, for example, of which only portions are usually observable in one field of view at higher magnifications.

Using a telescope

With a telescope, the sky really comes alive, especially one that has an aperture of six inches or more. Some amateur telescopes are built by their owners from scratch, but many good quality telescopes can be purchased from reputable companies. Thousands of Deep Sky Objects (DSOs) are visible in a telescope and the determined amateur with a large (about 41 cm) telescope can push this to tens of thousands or more.

Another type of telescope to consider, especially if the amateur is observing with children, is a wide-field telescope, such as Edmund Scientific's f/4 Astroscan compact reflector. This type of telescope is typically a short tube reflector and has an aperture of only 80 to 120 mm (3 1/4 to 4 3/4 inches), but is easier to target an object, since it offers a much wider field of view. With the aid of high power lenses (i.e. eyepieces), the amateur can zoom in on planets and some of the closer DSOs. It is the best of a blend of a telescope's narrow long range light gathering ability with a binocular's wider field of view.

Those who are particularly interested in observing the moon and planets may prefer a high-power design such as the Maksutov telescope.

With any telescope, though, the mount is the most important feature. A tripod that doesn't shake every time one uses it is a must. Too many amateur astronomers give up because they have a hard time targeting an object. If the mounting tripod is rock solid, the amateur can enjoy their time observing the heavens instead of fighting with the telescope.

Astrophotography

The next step in an amateur astronomer's quest for more space adventure could be the purchase of a good camera for Astrophotography. Starting out with a good 35 mm camera with a 50 mm lens mounted on a tripod and using a cable release and 400 or faster speed film, the amateur can capture some nice pictures of the planets and some larger nebula, like the Orion Nebula. Some of the larger comets and prolific meteor showers can be photographed this way as well.

As one progresses, cameras can be mounted directly on to telescopes, capturing on film many DSOs. Special films and even the technique of hypering the film has been employed by the amateur. Many publications accept these astrophotos in their magazines, i.e., Astronomy and Sky & Telescope.

A more recent development is the use of webcams to do speckle imaging (also known as video astronomy). The resulting short exposure frames can be stacked using the shift-and-add method of speckle imaging or selected to do lucky imaging, all using commercially available astronomy software.

Sketching

As an alternative to photography in order to make a record of observations, amateurs also use sketching. Sketching does not require the use of any specialized equipment and is therefore suitable for beginners as well as advanced amateur observers. There are different approaches to sketching that require different tools, simple pencil sketches can sometimes be used to make accurate renditions of what the observer sees through binoculars or a telescope. As the experience of the observer increases, more advanced drawing tools and techniques can be employed.

Sketching has the advantage of helping the observer scrutinize the object that is seen and can help bring out details that otherwise might have been overlooked.

External links

Night Sky Gazing - information for newcomers to the hobby
Astronomical League
Society for Popular Astronomy - the UK's biggest society for amateur astronomers
astroscopic labs - amateur astrophotography, reviews and articles
Waid Observatory - amateur observatory dedicated to CCD imagery
What Can I see in a Telescope - by Donald P. Waid
MMS - Australian Advanced Telescope Users
IceInSpace The Australian Amateur Astronomy Community
Society of Amateur Radio Astronomers
Cambridge Amateur Radio Astronomers
Amateur Search for Extraterrestrial Intelligence
The Night Sky This Week

Amateur astronomy | Amateur astronomy