The Galileoscope is a small mass-produced

refractor telescope A refracting telescope (also called a refractor) is a type of optical telescope that uses a lens (optics), lens as its objective (optics), objective to form an image (also referred to a dioptrics, dioptric telescope). The refracting telescope d ...

, designed with the intention of increasing public interest in

astronomy Astronomy () is a natural science that studies astronomical object, celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and chronology of the Universe, evolution. Objects of interest ...

and

science Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence for ...

. It was developed for the

International Year of Astronomy The International Year of Astronomy (IYA2009) was a year-long celebration of astronomy that took place in 2009 to coincide with the 400th anniversary of the first recorded astronomical observations with a telescope by Galileo Galilei and the pu ...

2009. It is meant to be an inexpensive means by which millions of people can view the same things seen by

Galileo Galilei Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642) was an Italian astronomer, physicist and engineer, sometimes described as a polymath. Commonly referred to as Galileo, his name was pronounced (, ). He was ...

, such as the craters of Earth's

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

, four of Jupiter's moons, and the

Pleiades The Pleiades (), also known as The Seven Sisters, Messier 45 and other names by different cultures, is an asterism and an open star cluster containing middle-aged, hot B-type stars in the north-west of the constellation Taurus. At a distance of ...

. The small telescope has an aperture of and a relatively long

focal length The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative foca ...

of 500 mm, for a

focal ratio In optics, the f-number of an optical system such as a camera lens is the ratio of the system's focal length to the diameter of the entrance pupil ("clear aperture").Smith, Warren ''Modern Optical Engineering'', 4th Ed., 2007 McGraw-Hill Pro ...

of f/10.

Design and configurations

The Galileoscope uses a focuser, giving the telescope a great deal of versatility, since this is the standard size for

eyepiece An eyepiece, or ocular lens, is a type of lens that is attached to a variety of optical devices such as telescopes and microscopes. It is named because it is usually the lens that is closest to the eye when someone looks through the device. The ...

s used in most amateur and some professional telescopes. This means the Galileoscope can be used with relatively cheap extra eyepieces to produce magnifications up to 100, or even 200 times (with a 5 mm in combination with the included 2×

Barlow lens The Barlow lens, named after Peter Barlow, is a diverging lens which, used in series with other optics in an optical system, increases the effective focal length of an optical system as perceived by all components that are after it in the system. ...

). However, a magnification of more than 125× would not be recommended for a scope this size because its focal ratio limits sharpness beyond this. Additionally, the design of the slide-in/out focusing tube, without any gears or knobs, makes it nearly impossible to focus above the 125× limit. It also utilizes

achromat An achromatic lens or achromat is a lens that is designed to limit the effects of chromatic and spherical aberration. Achromatic lenses are corrected to bring two wavelengths (typically red and blue) into focus on the same plane. The most comm ...

glass

lenses A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...

in the objective-lens – the large one in front – as well as in the eyepiece (4 lenses of two types of high quality plastic, known as a Plossl configuration) to prevent

chromatic aberration In optics, chromatic aberration (CA), also called chromatic distortion and spherochromatism, is a failure of a lens to focus all colors to the same point. It is caused by dispersion: the refractive index of the lens elements varies with the wave ...

, producing a clearer image. This is because single lenses, as are often used in cheap scopes, refract light of different colors in different angles (chromatic aberration). In practice this means all images will have blueish blurred edges on one side, reddish on the other, making the image very unclear. By using two types of glass for the two lenses this gets compensated to some degree, resulting in a sharper and clearer image. Depending on the configuration, 4, 6 or 8 lenses are used. The 4-lens configuration results in a telescope in some ways similar to Galileo's, with 17× magnification and a very small field of view. The 6-lens configuration provides 25× magnification, and the 8-lens configuration allows for 50× magnification. The user may easily switch between these configurations by changing the eyepiece.

References

External links

Specifications

Review
by

Phil Plait Philip Cary Plait (born September 30, 1964), also known as The Bad Astronomer, is an American astronomer, skeptic, and popular science blogger. Plait has worked as part of the Hubble Space Telescope team, images and spectra of astronomical objec ...

, author of BadAstronomy.com
Review on www.cloudynights.com was selected a gear of the year 2009
* http://www.galileoscope.org - the Galileoscope website *
Assembly instructionsThe moon viewed through a Galileoscope
{{Portal bar, Astronomy, Stars, Spaceflight, Outer space, Solar System Telescope manufacturers

Design and configurations

See also

References

External links