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mount designs for
Newtonian telescopes that have the "ball" built into the base of the optical tube assembly. These mounts have the advantage of being mechanically simple and allow the observer to rotate the eyepiece to any side of the telescope for easier viewing. Some types have even been adapted
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for equatorial tracking by motorizing one of the bearing surfaces to turn the ball at the rate of one revolution per day. This rotates the telescope's ball exactly opposite the rotation of the Earth, thus keeping the telescope stationary with respect to the stars.
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An advantage of infinite-axis telescopes is that there is no "dead-zone" where one axis must move infinitely fast in order to track the stars, as is the case with
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was mounted in this way; the ball was held in place by wrought iron springs. Another type uses a bowling balls as a mount axis. There are modern commercial and
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Another example of an infinite-axis telescope is a ball-in-cup mounted telescope, also called a spherical-mounted telescope. The first
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mounted on a ball joint were connected by a string; the observer kept the string tight and moved the eyepiece to aim the telescope.
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that can move freely in all directions. Such telescopes can be mechanically simple hand-guided versions with the
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Small, hand-held (richest-field) telescopes may also qualify as infinite-axis telescopes.
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An example of this type of telescope was the late 17th century "Air" or "
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serving only to carry the weight of the telescope although there are
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that did not use a tube. In these telescopes a hand held
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20:"Trackball" equatorial drive ball mount telescope
198:Homebuilt Astronomical Equipment and Observatory
194:"Hemispherical "Bowling Ball" Mount (deadlink)"
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159:List of telescope types
26:infinite-axis telescope
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211:Manly, Peter (1999),
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57:refracting telescope
72:Newtonian telescope
213:Unusual Telescopes
200:. 27 January 2023.
172:Unusual Telescopes
122:Newton's reflector
87:alt-azimuth mounts
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174:by Peter L. Manly
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54:focal length
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289:Outer space
277:Spaceflight
120:Replica of
40:versions.
317:Telescopes
180:References
38:equatorial
253:Astronomy
107:Astroscan
65:objective
30:telescope
311:Category
143:See also
61:eyepiece
34:mounting
239:Portals
93:Gallery
76:amateur
63:and an
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265:Stars
44:Types
28:is a
217:ISBN
24:An
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