Although the invention of the telescope dates back to 1608 and is credited to Dutch opticians, it was Italian scientist Galileo in 1609 who constructed a telescope that was based on the Dutch design and began to explore the cosmos rather than distant objects on Planet Earth. The first telescopes were refractors, which used lenses to magnify the image. Dissatisfied by the colored rings caused by lenses—an effect now referred to as chromatic aberration—Isaac Newton developed and built a telescope in 1668 that was six inches long, magnified objects by 40 times and instead used mirrors. The Newtonian Reflecting Telescope, or Newtonian Reflector, postdates the Gregorian telescope, an alternative design conceived in 1663 by James Gregory, a Scottish mathematician and astronomer. Another reflector variant was invented by French priest Laurent Cassegrain in 1672. In 1930, Bernhard Schmidt, an optician at the Hamburg Observatory in Bergedorf, Germany, designed a catadioptric telescope free of spherical aberration by combining optics from refractors and reflectors so large celestial areas could be photographed. Although the principles of the simple Galilean (Galileo) telescope are only used in low-powered opera glasses (binoculars) today, you will still see the names of Newton (Newtonian), Cassegrain and Schmidt associated with current-model reflectors.
The problem of seeing faint objects had largely been solved but finding them often proved time consuming. The night sky changes seasonally and is based on viewing location. Star charts offer guidance but using them under dark night skies may be difficult. In 1987, Celestron unveiled a computerized telescope that could locate (GoTo) and track the object of your choice from its database of more than 8,000 targets after polar alignment; entering the date, time and location (latitude and longitude); and first adjusting altitude and azimuth manually then electronically. A technologically advanced 8-inch telescope, introduced by Meade Instruments in 1992, became popular and sold for $2,795 in the late 1990s. It featured a 64,340-object celestial library and automatic GoTo capability after basic information entry like its predecessor (geographic coordinates, date and time) and a one-star alignment in ALTAZ mode. In 1999, a low-cost 3.5-inch computerized model billed as "one of the most revolutionary telescope systems ever developed" was released by Meade and could be purchased for just $750. It required polar alignment based on location.
Early attempts at astrophotography were about 230 years after Galileo constructed his telescope and were unsuccessful at first but it was John W. Draper in 1840 who is credited with successfully capturing the now renowned image of a Crescent Moon using the Daguerreotype process, thus earning him the title First Astrophotographer. (Based on the date it is believed to have been imaged, it is a Waning Crescent [after the Last Quarter phase] although different orientations of the same image suggest it could be Waxing [before the First Quarter].) Other successful images soon followed—1842: Partial Solar Eclipse, Gian A. Majocchi; Solar Spectrum, Alexandre E. Becquerel and John W. Draper, independently; 1843: The Sun, Armand H. Fizeau & Jean B. Foucault; 1851: The star Vega, George P. Bond & John A. Whipple.
While it's difficult to pinpoint, it was perhaps 120 years later during the 1960s that amateur astronomers began photographing celestial bodies using film. Unfortunately, you didn’t know what, if anything, you had captured until the film was developed, which is why digital cameras were quickly embraced when they became available because you could see the image you were capturing. However, mounting the digital camera on the telescope, connecting the camera to a PC and using software to capture and later manipulate images proved challenging even for experienced amateur astronomers—and costly.
In 2018, a new breed of telescopes began to emerge that greatly simplified and significantly reduced the cost of astrophotography and—at the same time—redefined Electronically Assisted Astronomy (EAA). Replacing a telescope's eyepiece with a camera connected to a display was originally considered EAA. Today, EAA refers to all-in-one devices that include the features and functions needed for astrophotography and are connected wirelessly to a smart device. Although the acronym EAA still applies, these devices are now universally called Smart Telescopes the chronology of which appears in the table below.
Smart telescopes combine a telescope, color camera, GoTo and tracking functions, and automatic image processing in a single device while a smartphone or tablet acts as your wireless remote control and displays images in real time. Being fully integrated, smart telescopes are quick to set up, self aligning, easy to use and amazingly small, especially considering their exceptional capability. As they continue to evolve, new features are being developed and AI's role is expanding.
If Galileo were alive today he would no doubt be astounded.
Chronology is sorted by date Released, Manufacturer and Model.
Image Title: Galileo offering his telescope to three women (possibly Urania and attendants) seated on a throne; he is pointing toward the sky where some of his astronomical discoveries are depicted. Created/Published: 1655