Amateur astronomy is a hobby where participants enjoy observing, studying, or imaging celestial objects in the sky using the unaided eye, binoculars, telescopes, and other gadgets. Although scientific research may not be their primary goal, some amateur astronomers contribute to citizen science by monitoring variable stars, double stars, sunspots, and occultations of stars by the Moon or asteroids, as well as by discovering transient astronomical events, such as comets, galactic novae or supernovae in other galaxies.
Amateur astronomers do not use the field of astronomy as their primary source of income or support, as well as typically having no professional degree in astrophysics or advanced academic training in the subject. Most amateur astronomers 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 a clearly distinguished activity 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 and solar eclipses. Some observe the sky using nothing more than their eyes or binoculars, while more dedicated amateurs often use portable telescopes or telescopes situated in their private or club observatories. However, light pollution has made amateur astronomy increasingly difficult to observe celestial objects, as sky glow washes out darkness and minimizes visibility. Amateurs commonly join amateur astronomical societies, which can advise, educate, or guide individuals towards ways of finding and observing celestial objects. Astronomical societies also promote the science of astronomy among the general public.
Objectives
Collectively, amateur astronomers observe a variety of celestial objects and phenomena. Common targets of amateur astronomers include the Sun, the Moon, planets, stars, comets, meteor showers, and a variety of deep sky objects such as star clusters, galaxies, and nebulae. Amateur astronomers purse their work in order to educate the public, make contributions to the scientific world, and express their passion. Many amateurs like to specialize 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 with the introduction of far easier to use equipment including digital cameras, DSLR cameras and relatively sophisticated purpose built high quality CCD cameras and CMOS cameras.
Most amateur astronomers work at visible wavelengths, but a small minority experiment with wavelengths outside the visible spectrum. An early pioneer of radio astronomy was Grote Reber, an amateur astronomer who constructed the first purpose-built radio telescope in the late 1930s to follow up on the discovery of radio wavelength emissions from space by Karl Jansky. 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 astronomical research but have since been made available for use by amateurs. The One-Mile Telescope is one such example.
Sidewalk astronomy — the practice of setting up telescopes for public viewing — aims at educating and engaging the public with astronomy. In addition to increasing interest in astronomy and science in general, sidewalk astronomy raises awareness of light pollution issues.
History The history of amateur astronomy dates back to early civilizations where the practice of observing celestial objects became a device that assisted in predicting atmospheric patterns to help enable proactive decisions on developing agriculture.Issitt, Micah L. "Amateur Astronomy." EBSCO Research Starters, 2022, www.ebsco.com/research-starters/history/amateur-astronomy. Civilizations like the Babylonians, Chaldeans, and ancient Egyptians created calendars, predicted eclipse dates, and separated day and night through ancient amateur astronomers using simple tools and the naked eye to track celestial bodies. Popularizing in the mid-nineteenth century, amateur astronomy gained millions of participants evolving from wealthy "Grand Amateurs" and the more accessible equipment after World War II.
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, and using a variety of optical 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. To further improve studying the visual and non-visual part of the spectrum, amateur astronomers go to rural areas to get away from light 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 on amateur telescope making as their primary interest within the hobby of amateur astronomy. More advanced methods of locating objects in the sky include telescope mounts with setting circles, which allow pointing to targets in the sky using celestial coordinates, and GOTO telescopes, which are fully automated telescopes that are capable of locating objects on demand (having first been calibrated).
Simple equipment Although specialized and experienced amateur astronomers tend to acquire more specialized and 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 and are more portable, which is preferable for looking at some objects in the night sky. Recent smartphone models have a "night mode" option when taking pictures that allows users to increase exposure, which refers to the period of time the picture is being taken. This optimizes focus on light in the frame which is why it is used primarily at night.
Beginner telescopes Beginner telescopes, commonly used by amateur astronomers to observe celestial objects in more detail, are a more powerful tool compared to other amateur equipment such as binoculars. Amateur astronomers often use four main types of optical telescopes: reflectors, refractors, hybrid, and Dobsonian telescopes. Reflector telescopes utilize mirrors while refractors use lenses, these combine to create the hybrid telescope, which uses a combination of both mirrors and lenses. The Dobsonian is a type of reflector with the addition of a base or mount.
GOTO telescopes have 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. 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 the Bareket Observatory, and there are telescope farms in New Mexico, Australia and Atacama in Chile.
Star charts Amateur astronomers also use star charts that, depending on experience and intentions, may range from simple planispheres through to star atlases with 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.
Setting circles
Setting circles are angular measurement scales that can be placed on the two main rotation axes of 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 the coordinates of an object (usually given in equatorial coordinates), the telescope user can use the setting circle to align (i.e., point) the telescope in the appropriate direction before looking through its eyepiece. 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. 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 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). 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.
Observing logs