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192:, the mass and cost of an equatorial mount is prohibitive and they have been superseded by computer-controlled altazimuth mounts. The simple structure of an altazimuth mount allows significant cost reductions, in spite of the additional cost associated with the more complex tracking and image-orienting mechanisms. An altazimuth mount also reduces the cost in the dome structure covering the telescope since the simplified motion of the telescope means the structure can be more compact.
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pointing. When tracking at elevations close to 90°, the azimuth axis must rotate very quickly; if the altitude is exactly 90°, the speed is infinite. Thus, altazimuth telescopes, although they can point in any direction, cannot track smoothly within a "zenith blind spot", commonly 0.5 or 0.75 degrees
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120:, the biggest advantage of an alt-azimuth mount is the simplicity of its mechanical design. The primary disadvantage is its inability to follow astronomical objects in the
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at the THÉMIS experimental station in France. The mirror rotates on an alt-azimuth mount. The pointing direction of the mirror is perpendicular to its surface.
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because of its ease of construction; Dobson's innovation was to use non-machined parts for the mount that could be found in any hardware store such as
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based two-axis drive systems, to track equatorial motion. This imparts an uneven rotation to the field of view that also has to be corrected via a
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is sometimes used to add a third "polar axis" to overcome these problems, providing an hour or more of motion in the direction of
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238:" telescopes: It has often proved more convenient to build a mechanically simpler altazimuth mount and use a
58:(compass bearing) of the pointing direction of the instrument. Rotation about the horizontal axis varies the
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only needs to be rotated about a single axis, at a constant rate, to follow the rotation of the night sky (
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to manipulate both axes simultaneously to track an object, when compared with a more mechanically complex
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to allow for astronomical tracking. The design also does not allow for the use of mechanical
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Mahra, H. S.; Karkera, B. N. (1985). "Field rotation with altazimuth mounting telescope".
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axes – one vertical and the other horizontal. Rotation about the vertical axis varies the
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from the zenith. (i.e. at elevations greater than 89.5° or 89.25° respectively.)
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349:– a system to locate objects on the celestial sphere via Alt-azimuth coordinates
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Typical current applications of altazimuth mounts include the following.
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Support mechanism with rotation about the horizontal and vertical axes
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Beginner telescopes: Altazimuth mounts are cheap and simple to use.
462:, W.M. Keck Observatory, p. 5, Keck Adaptive Optics Note 708
223:, and plastic plumbing parts combined with modern materials like
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Léna, Pierre; Lebrun, François; Mignard, François (1998-01-01).
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Limits to AO Observations from
Altitude-Azimuth Telescope Mounts
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is essentially an alt-azimuth mount for a gun, and a standard
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510:(1985). "Design for a large altazimuth Schmidt telescope".
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that requires minimally complex control of a single motor.
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Several names are given to this kind of mount, including
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based counter rotation system. On smaller telescopes an
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Occasional
Reports of the Royal Observatory, Edinburgh
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popularized a simplified altazimuth mount design for
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280:One of the 8.2 m (320 in) telescopes at
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62:(angle of elevation) of the pointing direction.
156:to locate astronomical objects although modern
304:and accessories) on a small alt-azimuth mount.
384:Bulletin of the Astronomical Society of India
537:Marx, Siegfried; Pfau, Werner (1992-06-11).
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540:Astrophotography with the Schmidt telescope
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453:Neyman, Christopher (February 10, 2010),
128:spins on its axis. On the other hand, an
65:These mounts are used, for example, with
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112:Astronomical telescope altazimuth mounts
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567:Images of the Unitron altazimuth mount
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163:Another limitation is the problem of
100:and various abbreviations thereof. A
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116:When used as an astronomical
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482:Observational astrophysics
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46:mount for supporting and
50:an instrument about two
158:digital setting circles
410:Vogel, Reiner (2007).
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433:"Telescope Structure"
412:"Equatorial Platform"
89:and similar weapons.
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435:. Gemini Observatory
298:refracting telescope
213:Newtonian reflectors
205:Dobsonian telescopes
176:Current applications
524:1985ORROE..16...15D
397:1985BASI...13...88M
282:Paranal Observatory
184:Research telescopes
146:equatorial platform
25:Newtonian telescope
196:Amateur telescopes
190:largest telescopes
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353:Parallactic angle
240:motion controller
98:azimuth-elevation
40:alt-azimuth mount
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337:Equatorial mount
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324:Astronomy portal
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244:equatorial mount
130:equatorial mount
94:altitude-azimuth
42:is a simple two-
36:altazimuth mount
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29:Dobsonian mount
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134:diurnal motion
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75:radio antennas
60:altitude angle
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83:solar panels
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27:on a simple
302:finderscope
209:John Dobson
165:gimbal lock
582:Telescopes
466:2015-08-08
439:2015-08-08
417:16 January
369:References
102:gun turret
67:telescopes
518:: 15–18.
391:(1): 88.
342:Heliostat
266:heliostat
122:night sky
81:mirrors,
79:heliostat
576:Category
310:See also
48:rotating
520:Bibcode
393:Bibcode
251:Gallery
221:formica
217:plywood
188:In the
124:as the
71:cameras
56:azimuth
547:
489:
363:Tripod
300:(with
229:teflon
169:zenith
85:, and
460:(PDF)
225:nylon
126:Earth
545:ISBN
487:ISBN
419:2014
236:GoTo
87:guns
44:axis
227:or
167:at
38:or
34:An
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516:16
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389:13
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296:A
264:A
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