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Amateur astronomers watch the night sky during the Perseid meteor shower
Amateur astronomers watch the night sky during the Perseid meteor shower

Amateur astronomy, a subset of astronomy, is a hobby whose participants enjoy studying and observing celestial objects. The Perseids (ˈpɝsiːɨdz pûr'sē-ĭdz is a prolific Meteor shower associated with the Comet Swift-Tuttle. Astronomy (from the Greek words astron (ἄστρον "star" and nomos (νόμος "law" is the scientific study A hobby is a spare-time Recreational pursuit Etymology A Hobby horse is a wooden or Wickerwork toy made to be

Contents

Overview

The amateur astronomer is one who does not depend on the field of astronomy as a primary source of income or support, and does not have a professional degree or advanced academic training. Income, refers to consumption opportunity gained by an entity within a specified time frame which is generally expressed in monetary terms A first professional degree is a type of Academic degree designed to prepare the holder for a particular profession by emphasizing practical skills over theory and analysis Many amateurs are beginners, while others have a high degree in astronomy and often assist and work alongside professional astronomers.

Amateur astronomy 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. A sunspot is a region on the Sun 's surface ( Photosphere) that is marked by intense magnetic activity which inhibits Convection, forming A solar eclipse occurs when the Moon passes between the Sun and the Earth so that the Sun is wholly or partially obscured Amateur astronomers often look at the sky using nothing more than their eyes, but common tools for amateur astronomy include portable telescopes and binoculars. An optical telescope is a Telescope which is used to gather and focus light mainly from the visible part of the Electromagnetic spectrum Binocular telescopes, or binoculars (also known as field glasses are two identical or Mirror - symmetrical telescopes mounted side-by-side and

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. A phenomenon (from Greek φαινόμενoν, pl φαινόμενα - phenomena) is any observable occurrence 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. A planet, as defined by the International Astronomical Union (IAU is a celestial body Orbiting a Star or stellar remnant that is A star is a massive luminous ball of plasma. The nearest star to Earth is the Sun, which is the source of most of the Energy on Earth A comet is a small Solar System body that orbits the Sun and when close enough to the Sun exhibits a visible coma (atmosphere or a tail — A meteor shower, some of which are known as a "meteor storm" or "meteor outburst" is a celestial event where a group of meteors are observed to radiate from one point Deep sky or Deep Sky Object (DSO for short which differs from Deep space, is a term used by amateur astronomers to describe mostly faint Astronomical objects outside Star clusters are groups of Stars which are gravitationally bound A galaxy is a massive gravitationally bound system consisting of Stars an Interstellar medium of gas and dust, and Dark matter A nebula (from Latin: "mist" pl nebulae or nebulæ, with ligature or nebulas) is an Interstellar cloud of 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 is a specialized type of Photography that entails making photographs of astronomical objects in the sky such as the Moon, Sun, Planets Astrophotography has become more popular for amateurs in recent times, as relatively sophisticated equipment, such as high quality CCD cameras, has become more affordable. A charge-coupled device ( CCD) is an analog Shift register, that enables the transportation of analog signals (electric charges through successive stages (capacitors

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. Karl Guthe Jansky ( October 22, 1905 &ndash February 14, 1950) was an American Physicist and Radio Engineer Radio frequency ( RF) is a Frequency or rate of Oscillation within the range of about 3 Hz to 300 GHz Non-visual amateur astronomy includes the use of infrared filters on conventional telescopes, and also the use of radio telescopes. An infrared filter is a filter to remove visible light and only pass Infrared light in different Wavelengths These are mainly used in Infrared photography A radio telescope is a form of directional Radio antenna used in Radio astronomy and in tracking and collecting data from Satellites 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. The One-Mile Telescope at the Mullard Radio Astronomy Observatory (MRAO was completed by the Radio Astronomy Group of Cambridge University in 1964

Common tools

Amateur astronomers use a range of instruments to study the sky, depending on a combination of their interests and resources. The sky is the part of the Atmosphere or of Outer space visible from the surface of any Astronomical object. Methods include simply looking at the night sky with the naked eye, using binoculars, and 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 parts of the spectrum. The naked eye is a Figure of speech referring to human Visual perception that is unaided by enhancing equipment such as a Telescope or Binocular telescopes, or binoculars (also known as field glasses are two identical or Mirror - symmetrical telescopes mounted side-by-side and A telescope is an instrument designed for the observation of remote objects and the collection of Electromagnetic radiation. A camera is a device used to capture images either as still Photographs or as sequences of moving images ( Movies or Videos. A spectrum (plural spectra or spectrums) is a condition that is not limited to a specific set of values but can vary infinitely within a continuum. 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. The field of amateur telescope making is considered an offshoot of the Amateur astronomy community

Although specialised and experienced amateur astronomers tend to acquire more specialised and more powerful equipment over time, relatively simple equipment is often preferred for certain tasks. Binoculars, for instance, although generally of 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. The field of view (also field of vision) is the angular extent of the observable world that is seen at any given moment

Amateur astronomers also use star charts that, depending on experience and intentions, may range from simple planispheres through to detailed charts of very specific areas of the night sky. A star chart is a map of the Night sky. Astronomers divide these into grids to easily use them 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 usually takes 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.

The Internet is an essential tool of amateur astronomers. Almost all astronomy clubs, even those with very few members, have a web site. The popularity of CCD imaging among amateurs means large numbers of web sites written by individuals about their images and equipment. Much of the social interaction of amateur astronomy occurs on mailing lists or discussion groups. Yahoo groups and Google groups host numerous astronomy lists. A great deal of the commerce of amateur astronomy, the buying and selling of equipment, occurs online. Many amateurs use online tools to plan their nightly observing sessions using tools such as the Clear Sky Chart. Clear Sky Charts (called "clocks" until 2008-02-29 are web graphics which deliver Weather forecasts designed specifically for astronomers.

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

Star hopping is a method often used by amateur astronomers with low-tech equipment such as binoculars or a manually driven telescope. Star hopping is a technique that is often used by amateur astronomers to locate objects in the night sky It involves the use of maps (or memory) to locate known landmark stars, and "hopping" between them. Originally a landmark literally meant a Geographic Feature used by explorers and Because of its simplicity, star hopping is a very common method for finding objects that are close to naked-eye stars. Simplicity is the property condition or quality of being simple or un-combined

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). Calibration is the process of establishing the relationship between a measuring device and the units of measure

Setting circles

Setting circles are angular measurement scales that can be placed on the two main rotation axes of some telescopes. Setting circles are used on Telescopes equipped with an Equatorial mount to find astronomical objects in the sky by their equatorial coordinates often used In Geometry and Trigonometry, an angle (in full plane angle) is the figure formed by two rays sharing a common Endpoint, called Since the widespread adoption of digital setting circles, any classical engraved setting circle is now specifically identified as an "analog setting circle" (ASC). By knowing the coordinates of an object (usually given in equatorial coordinates), the telescope user can use the setting circle to align the telescope in the appropriate direction before looking through its eyepiece. In Mathematics and its applications a coordinate system is a system for assigning an n - Tuple of Numbers or scalars to each point The equatorial coordinate system is probably the most widely used Celestial coordinate system, whose equatorial coordinates are Declination (\delta For the device for looking through a camera see Viewfinder. An eyepiece, or ocular lens, is a type of lens that is attached A computerized setting circle is called a "digital setting circle" (DSC). Although digital setting circles can be used to display a telescope's RA and Dec coordinates, they are not simply a digital read-out of what can be seen on the telescope's analog setting circles. Right ascension (abbrev RA; symbol α) is the Astronomical term for one of the two Coordinates of a point on the Celestial sphere In Astronomy, declination (abbrev dec or δ) is one of the two coordinates of the Equatorial coordinate system, the other being either As with go-to telescopes, digital setting circle computers (commercial names include Argo Navis, Sky Commander, and NGC Max) actually contain databases of tens of thousands of celestial objects and projections of planet positions.

To find an object, such as globular cluster NGC 6712, one does not need to look up the RA and Dec coordinates in a book, and then move the telescope to those numerical readings. NGC 6712 is a Globular cluster that was probably discovered by Le Gentil on July 9 1749 when investigating the Milky Way star Rather, the object is chosen from the database and arrow markers appear in the display which indicate the direction to move the telescope. The telescope is moved until the distance value reaches zero. When both the RA and Dec axes are thus "zeroed out", the object should be in the eyepiece. The user therefore does not have to go back and forth from some other database (such as a book or laptop) to match the desired object's listed coordinates to the coordinates on the telescope. However, many DSCs, and also go-to systems, can work in conjunction with laptop sky programs.

Computerized systems provide the further advantage of computing coordinate precession. Traditional printed sources are subtitled by the epoch year, which refers to the positions of celestial objects at a given time to the nearest year (e. g. , J2005, J2007). Most such printed sources have been updated for intervals of only about every fifty years (e. g. , J1900, J1950, J2000). In Astronomy, an epoch is a moment in time used as a reference for the Orbital elements of a Celestial body. In Astronomy, an epoch is a moment in time used as a reference for the Orbital elements of a Celestial body. In Astronomy, an epoch is a moment in time used as a reference for the Orbital elements of a Celestial body. Computerized sources, on the other hand, are able to calculate the right ascension and declination of the "epoch of date" to the exact instant of observation.

GoTo telescopes

Meade ETX 90 Telescope, a small domestic GOTO telescope
Meade ETX 90 Telescope, a small domestic GOTO telescope

GOTO telescopes have become more popular in recent times as technology has improved and prices have been reduced. In amateur astronomy, " GoTo " refers to a type of telescope mount and related Software which can automatically point a telescope to 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. Research is defined as Human activity based on Intellectual application in the investigation of Matter. For example, GOTO telescopes tend to be faster for locating items of interest than star hopping, allowing more time for studying of the object. GOTO also allows manufacturers to add equatorial tracking to mechanically simpler alt-azmuth telescope mounts, allowing them to produce an over all less expensive product.

Because GOTO telescopes have become increasingly affordable, a new type of beginning amateur astronomer has emerged, in that 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.

The GoTo debate

In the early 1990s, the amateur astronomy community engaged in some debate, usually light-hearted, about which method is superior. Some astronomers argued 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. Star hopping involves the use of printed media that is dependent on computer generated sources. The user prints out star maps at home or uses books, atlases, and magazine articles that have computer generated graphics in them to aid in the quest to find an object.

GOTO telescopes, on the other hand, do make the hobby more accessible. They may be preferred by people who are more serious about studying objects, because less time and effort are required for finding objects when they are well prepared. But digital setting circle or go-to systems also provide touring functions whereby the user can set parameters such as magnitude and class of object, and, for example, view a series of planetary nebulae in Cygnus. The apparent magnitude ( m) of a celestial body is a measure of its Brightness as seen by an observer on Earth, normalized to the value A planetary nebula is an Emission nebula consisting of a glowing shell of Gas and plasma formed by certain types of Stars when they die Cygnus (ˈsɪgnəs Swan, Κύκνος) is a northern Constellation. A user who has discovered that his list of close double stars is impossible to view because of the seeing conditions can select an alternative viewing program within minutes. Double Star is a Science fiction Novel by Robert A Heinlein, first serialized in Astounding Science Fiction Many middle-aged and older amateur astronomers discovered that electronic pointing systems not only were convenient but spared them the difficult postures and associated aches and pains that go with pointing a telescope at zenith (with the common straight-through finder) or near to the horizon (on elevated mounts the finder can be out of reach). In broad terms the zenith is the direction pointing directly above a particular location ( Perpendicular, Orthogonal) The horizon ( Ancient Greek ὁ ὁρίζων, /ho horídzôn/ from ὁρίζειν, "to limit" is the apparent line that separates The explosion of astrophotography, in which a webcam or CCD camera is mounted on a telescope and downloads data to a nearby laptop, further enhanced demand for robotic systems that would point the telescope while the operator could stay seated and set imaging parameters. Webcams ( web cameras) are small cameras (usually though not always Video cameras, whose images can be accessed using the World Wide Web, instant A charge-coupled device ( CCD) is an analog Shift register, that enables the transportation of analog signals (electric charges through successive stages (capacitors A robotic telescope is an astronomical Telescope and detector system that makes Observations without the intervention of a Human.

Imaging techniques

Amateur astronomers engage in many imaging techniques including film and CCD astrophotography. A charge-coupled device ( CCD) is an analog Shift register, that enables the transportation of analog signals (electric charges through successive stages (capacitors Astrophotography is a specialized type of Photography that entails making photographs of astronomical objects in the sky such as the Moon, Sun, Planets Because CCD imagers are linear, image processing may be used to subtract away the effects of lightpollution, which has increased the popularity of astrophotography in urban areas. Image processing is any form of Signal processing for which the input is an image such as photographs or frames of video the output of image processing can be either an image

Scientific research

Scientific research is most often not the main goal for many amateur astronomers, unlike professional astronomy. Scientific method refers to bodies of Techniques for investigating phenomena 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 Astronomical Society of the Pacific (ASP is a scientific and educational organization founded in San Francisco in 1889. The Amateur Achievement Award recognizes "significant contributions to Astronomy or amateur astronomy by those not employed in the field of astronomy in a professional

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. For the astronomical object see Variable star. Variable Star is a 2006 novel written by Spider Robinson Asteroids, sometimes called Minor planets or planetoids', are bodies—primarily of the inner Solar System —that are smaller than planets but In Shia Islam The Occultation is a term used to designate the hidden state of the Imam of the Time. 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 role 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. The Kreutz Sungrazers (ˈkrɔɪts are Sungrazing comets of a particular family

In the past and present, amateur astronomers have played a major role in discovering new comets. A comet is a small Solar System body that orbits the Sun and when close enough to the Sun exhibits a visible coma (atmosphere or a tail — 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. The LI ncoln N ear- E arth A steroid R esearch ( LINEAR) project is a cooperative project between the United States Air Force Near Earth Asteroid Tracking (NEAT is a program run by NASA and Jet Propulsion Laboratory to discover Near-Earth objects The NEAT system began observations

Societies

There is 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. Light pollution, also known as photopollution or luminous pollution, is excess or obtrusive Light created mainly by Humans Among other effects

It is common for local societies to hold regular meetings, which may include activities such as star parties or presentations. A star party is a gathering of amateur astronomers for the purpose of observing the sky Societies are also a meeting point for people with particular interests, such as amateur telescope making. The field of amateur telescope making is considered an offshoot of the Amateur astronomy community

Famous amateur astronomers

References

See also

Amateur astronomy organizations:

Prizes recognizing amateur astronomers:

Further reading

External links

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