Amateur astronomy

"Amateur astronomer", "Popular astronomy", "Skygazing", and "Stargazing" redirect here. For the magazine, seeThe Amateur Astronomer.For Buddhist practice, seeSky gazing (Dzogchen).For other uses, seeStargazing (disambiguation)andPopular Astronomy (disambiguation).

Amateur astronomyis ahobbywhere participants enjoy observing or imagingcelestial objectsin theskyusing theunaided eye,binoculars,ortelescopes.Even though scientific research may not be their primary goal, some amateur astronomers make contributions in doingcitizen science,such as by monitoringvariable stars,double stars,sunspots,oroccultationsofstarsby theMoonorasteroids,or by discoveringtransient astronomical events,such ascomets,galacticnovaeorsupernovaein othergalaxies.

Amateur astronomers watch the night sky during thePerseidmeteor shower.

Amateur astronomers do not use the field ofastronomyas their primary source of income or support, and usually have no professional degree in astrophysics or advanced academic training in the subject. Most amateurs are hobbyists, while others have a high degree of experience in astronomy and may often assist and work alongside professional astronomers.Many astronomers have studied the sky throughout history in an amateur framework; however, since the beginning of the twentieth century, professional astronomy has become an activity clearly distinguished from amateur astronomy and associated activities.

Amateur astronomers typically view the sky at night, when most celestial objects and astronomical events are visible, but others observe during the daytime by viewing the Sun andsolar eclipses.Some just look at the sky using nothing more than their eyes or binoculars, but more dedicated amateurs often use portabletelescopesor telescopes situated in their private or clubobservatories.Amateurs also join amateurastronomical societies,which can advise, educate or guide them towards ways of finding and observing celestial objects. They also promote the science of astronomy among the general public.

Objectives

Amateur astronomer recording observations of the sun.

Collectively, amateur astronomers observe a variety of celestial objects and phenomena. Common targets of amateur astronomers include theSun,theMoon,planets,stars,comets,meteor showers,and a variety ofdeep sky objectssuch asstar clusters,galaxies,andnebulae.Many amateurs like to specialise in observing particular objects, types of objects, or types of events which interest them. One branch of amateur astronomy, amateurastrophotography,involves the taking of photos of the night sky. Astrophotography has become more popular with the introduction of far easier to use equipment including, digital cameras, DSLR cameras and relatively sophisticated purpose built high qualityCCD camerasandCMOS cameras.

Most amateur astronomers work at visiblewavelengths,but a small minority experiment with wavelengths outside thevisible spectrum.An early pioneer ofradio astronomywasGrote Reber,an amateur astronomer who constructed the first purpose-builtradio telescopein the late 1930s to follow up on the discovery ofradio wavelengthemissions from space byKarl Jansky.Non-visual amateur astronomy includes the use ofinfrared filterson conventional telescopes, and also the use ofradio telescopes.Some amateur astronomers use home-made radio telescopes, while others use radio telescopes that were originally built for astronomical research but have since been made available for use by amateurs. TheOne-Mile Telescopeis one such example.

Common tools

Places likeParanal Observatoryoffer crystal clear skies for observing astronomical objects with or without instruments.

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, and using a variety ofoptical telescopesof 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. To further improve studying the visual and non-visual part of the spectrum, amateur astronomers go to rural areasto get away fromlight pollution.Commercial telescopes are available, new and used, but it is also common for amateur astronomers to build (or commission the building of) their own custom telescopes. Some people even focus onamateur telescope makingas their primary interest within the hobby of amateur astronomy.

Although specialized and experienced amateur astronomers tend to acquire more specialized 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 widerfield of view,which is preferable for looking at some objects in the night sky. Recent models of iPhones have introduced a "night mode"option when taking pictures as well, that allows you to increase exposure, which is a period of time the picture is being taken for. This optimizes focus on light in the frame which is why it is used primarily at night.

Amateur astronomers also usestar chartsthat, depending on experience and intentions, may range from simpleplanispheresthrough tostar atlaseswith detailed charts of the entire night sky. A range of astronomy software is also available and used by amateur astronomers, including software that generates maps of the sky, software to assist with astrophotography, observation scheduling software, 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 information gathered is used to help studies and interactions between amateur astronomers in yearly gatherings. Although not professional information or credible, it is a way for the hobby lovers to share their new sightings and experiences.

The popularity of imaging among amateurs has led to large numbers of web sites being written by individuals about their images and equipment. Much of the social interaction of amateur astronomy occurs on mailing lists or discussion groups. Discussion group servers 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 theClear Sky Chart.

Common techniques

While a number of interesting celestial objects are readily identified by the naked eye, sometimes with the aid of a star chart, many others are so faint or inconspicuous that technical means are necessary to locate them. Although many methods are used in amateur astronomy, most are variations of a few specific techniques.

Star hopping

Main article:Star hopping

Star hoppingis 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, often with the aid of afinderscope.Because of its simplicity, star hopping is a very common method for finding objects that are close to naked-eye stars.

More advanced methods of locating objects in the sky includetelescope mountswithsetting circles,which allow pointing to targets in the sky usingcelestial coordinates,andGOTO telescopes,which are fully automated telescopes that are capable of locating objects on demand (having first been calibrated).

Mobile apps

The advent ofmobile applicationsfor use in smartphones has led to the creation of many dedicated apps.These apps allow any user to easily locate celestial objects of interest by simply pointing the smartphone device in that direction in the sky. These apps make use of the inbuilt hardware in the phone, such asGPSlocation andgyroscope.Useful information about the pointed object like celestial coordinates, the name of the object, its constellation, etc. are provided for a quick reference. Some paid versions give more information. These apps are gradually getting into regular use during observing, for the alignment process of telescopes.

Setting circles

Main article:Setting circles

Setting circlesareangular measurementscales that can be placed on the two mainrotation axesof some telescopes.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 thecoordinatesof an object (usually given inequatorial coordinates), the telescope user can use the setting circle to align (i.e., point) the telescope in the appropriate direction before looking through itseyepiece.A computerized setting circle is called a "digital setting circle" (DSC). Although digital setting circles can be used to display a telescope'sRAandDeccoordinates, they are not simply a digital read-out of what can be seen on the telescope's analog setting circles. As with go-to telescopes, digital setting circle computers (commercial names include Argo Navis, Sky Commander, and NGC Max) contain databases of tens of thousands of celestial objects and projections of planet positions.

To find a celestial object in a telescope equipped with a DSC computer, one does not need to look up the specific RA and Dec coordinates in a book or other resource, and then adjust the telescope to those numerical readings. Rather, the object is chosen from the electronic database, which causes distance values and arrow markers to appear in the display that indicate the distance and direction to move the telescope. The telescope is moved until the two angular distance values reach zero, indicating that the telescope is properly aligned. When both the RA and Dec axes are thus "zeroed out", the object should be in the eyepiece. Many DSCs, like go-to systems, can also work in conjunction with laptop sky programs.

Computerized systems provide the further advantage of computing coordinate precession. Traditional printed sources are subtitled by theepochyear,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). 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

Main article:GoTo (telescopes)

GOTO telescopeshave become more popular since the 1980s as technology has improved and prices have been 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. GOTO also allows manufacturers to add equatorial tracking to mechanically simpler alt-azimuth telescope mounts, allowing them to produce an overall less expensive product. GOTO telescopes usually have to be calibrated using alignment stars to provide accurate tracking and positioning. However, several telescope manufacturers have recently developed telescope systems that are calibrated with the use of built-in GPS, decreasing the time it takes to set up a telescope at the start of an observing session.

Remote-controlled telescopes

With the development of fast internet in the last part of the 20th century along with advances in computer controlled telescope mounts and CCD cameras, "remote telescope" astronomy is now a viable means for amateur astronomers not aligned with major telescope facilities to partake in research and deep sky imaging. This enables anyone to control a telescope a great distance away in a dark location. The observer can image through the telescope using CCD cameras. The digital data collected by the telescope is then transmitted and displayed to the user by means of the Internet. An example of a digital remote telescope operation for public use via the Internet is theBareket observatory,and there are telescope farms in New Mexico,Australia andAtacamain Chile.

Imaging techniques

Main article:Amateur astrophotography

An image of theCat's Paw Nebulacreated combining the work of professional and amateur astronomers. The image is the combination of the 2.2-metre MPG/ESO telescope of the La Silla Observatory in Chile and a 0.4-meter amateur telescope.

Amateur astronomers engage in many imaging techniques including film,DSLR,LRGB,andCCDastrophotography.Because CCD imagers are linear,image processingmay be used to subtract away the effects of light pollution, which has increased the popularity of astrophotography in urban areas. Narrowband filters may also be used to minimize light pollution.

Scientific research

Scientific research is most often not themaingoal for many amateur astronomers, unlike professional astronomers. 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 recognize this, theAstronomical Society of the Pacificannually givesAmateur Achievement Awardsfor 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 organizations, such as theAmerican Association of Variable Star Observersand theBritish Astronomical Association,exist to help coordinate these contributions.

Amateur astronomers often contribute toward activities such as monitoring the changes in brightness ofvariable starsandsupernovae,helping to trackasteroids,and observingoccultationsto determine both the shape of asteroids and the shape of the terrain on the apparent edge of theMoonas 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 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.

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

Societies

Main article:List of astronomical societies

Amateur astronomy groups are often involved in outreach to introduce astronomy to the general public

There are a large number of amateurastronomical societiesaround the world, that serve as a meeting point for those interested in amateur astronomy. Members range from active observers with their own equipment to "armchair astronomers" who are simply interested in the topic. Societies range widely in their goals and activities, which may depend on a variety of factors such as geographic spread, local circumstances, size, and membership. For example, a small local society located in dark countryside may focus on practical observing andstar parties,whereas a large one based in a major city might have numerous members but be limited by light pollution and thus hold regular indoor meetings with guest speakers instead. Major national or international societies generally publish their own academic journal or newsletter, and some hold large multi-day meetings akin to a scientific conference or convention. They may also have sections devoted to particular topics, such aslunar observationoramateur telescope making.

Notable contributions by amateur astronomers

Further information:Category:Amateur astronomers

Sir Patrick Moorewas one of the world's leading popularisers of astronomy.

There have been many significant scientific, technological, and cultural contributions made by amateur astronomers:

• George Alcock,one of the most successful visual discoverers comets and novae.
• John E. Bortle,authored ' "Comet Digest" inSky and Telescopemagazine and the monthly AAVSO circular for theAmerican Association of Variable Star Observers.Created theBortle scaleto quantify the darkness of the night sky.
• Robert Burnham Jr.(1931–1993), author of theCelestial Handbook.
• Andrew Ainslie Common(1841–1903), built his own very large reflecting telescopes and demonstrated that photography could record astronomical features invisible to the human eye.
• Robert E. Cox(1917–1989) who conducted the "Gleanings for ATMs" column inSky & Telescopemagazine for 21 years.
• John Dobson(1915–2014), promoter of astronomy whose name is associated with theDobsonian telescope.
• Robert Owen Evans(1937–2022) was an amateur astronomer who currently holds the all-time record for visual discoveries ofsupernovae.
• Giuseppe Donatiello,discovered eleven nearbydwarf galaxiesin theLocal Volumeincluding the first galaxy to be named after its non-professional discoverer..
• Will Hay,the famous comedian and actor, who discovered a white spot on Saturn.
• Walter Scott Houston(1912–1993) who wrote the "Deep-Sky Wonders" column inSky & Telescopemagazine for almost 50 years.
• Albert G. Ingalls(1888–1958), editor ofAmateur Telescope Making, Vols. 1–3and "The Amateur Scientist".
• David H. Levydiscovered or co-discovered 22 comets includingComet Shoemaker-Levy 9,the most for any individual.
• Sir Patrick Moore(1923–2012), presenter of the BBC's long-runningThe Sky at Nightand author of many books on astronomy.
• Russell W. Porter(1871–1949) foundedStellafaneand has been referred to as a "founder" ofamateur telescope making.
• Grote Reber(1911–2002), pioneer ofradio astronomyconstructing the first purpose-builtradio telescopeand conducted the firstsky surveyin the radio frequency.

Citizen science projects

Amateur astronomers and other non-professionals make contributions through ongoing citizen science projects:

• XO Project,an international team of amateur and professional astronomers tasked with identifying extrasolar planets.
• Many amateur astronomers contribute to scientific discoveries as part of the citizen scienceZooniverseproject.

Prizes recognizing amateur astronomers

• Amateur Achievement Award of Astronomical Society of the Pacific
• Chambliss Amateur Achievement Award

See also

• Astronomical object
• Caldwell catalogueA list of astronomical objects for observation by amateur astronomers compiled by Sir Patrick Caldwell-Moore.
• Clear Sky ChartWeather forecasts designed for amateur astronomers.
• List of astronomical societies
• List of telescope parts and construction
• Messier catalogueA set of astronomical objects catalogued by the French astronomer Charles Messier in 1771, which is still used by many amateurs as an observing list.
• Observation
• Observational astronomy
• School Astronomical Olympiad by Correspondence
• Sidewalk astronomy
• Skygazing
• Star party

Further reading

• Timothy Ferris(2002).Seeing in the Dark: How Backyard Stargazers Are Probing Deep Space and Guarding Earth from Interplanetary Peril.New York: Simon & Schuster.ISBN978-0-684-86579-9.
• P. Clay Sherrod; Thomas L. Koed (2003).A Complete Manual of Amateur Astronomy: Tools and Techniques for Astronomical Observations.Mineola, N.Y.: Dover Publications.ISBN978-0-486-42820-8.
• Mousis, O.; et al. (2014). "Instrumental methods for professional and amateur collaborations in planetary astronomy".Experimental Astronomy.38(1–2): 91–191.arXiv:1305.3647.Bibcode:2014ExA....38...91M.doi:10.1007/s10686-014-9379-0.S2CID118513531.

External links

• Amateur Astronomy Magazine