130:
115:
17:
272:
296:
101:
248:
284:
260:
78:
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
79:
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.
85:
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
74:
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
70:
Another example of an infinite-axis telescope is a ball-in-cup mounted telescope, also called a spherical-mounted telescope. The first
67:
mounted on a ball joint were connected by a string; the observer kept the string tight and moved the eyepiece to aim the telescope.
170:
220:
114:
32:
that can move freely in all directions. Such telescopes can be mechanically simple hand-guided versions with the
129:
238:
153:
75:
158:
121:
56:
82:
Small, hand-held (richest-field) telescopes may also qualify as infinite-axis telescopes.
8:
316:
300:
71:
288:
276:
193:
216:
252:
148:
135:
86:
49:
37:
33:
64:
100:
310:
264:
53:
48:
An example of this type of telescope was the late 17th century "Air" or "
16:
106:
36:
serving only to carry the weight of the telescope although there are
29:
60:
259:
59:
that did not use a tube. In these telescopes a hand held
236:
20:"Trackball" equatorial drive ball mount telescope
308:
198:Homebuilt Astronomical Equipment and Observatory
194:"Hemispherical "Bowling Ball" Mount (deadlink)"
215:, Cambridge University Press, p. 91,
15:
309:
210:
13:
164:
14:
328:
232:
294:
282:
270:
258:
246:
128:
113:
99:
204:
186:
1:
179:
7:
142:
10:
333:
92:
52:", which was a very long
154:History of the telescope
43:
159:List of telescope types
26:infinite-axis telescope
21:
211:Manly, Peter (1999),
19:
57:refracting telescope
72:Newtonian telescope
213:Unusual Telescopes
200:. 27 January 2023.
172:Unusual Telescopes
122:Newton's reflector
87:alt-azimuth mounts
22:
174:by Peter L. Manly
324:
299:
298:
297:
287:
286:
285:
275:
274:
273:
263:
262:
251:
250:
249:
242:
226:
225:
208:
202:
201:
190:
149:Aerial telescope
136:Aerial telescope
132:
117:
103:
50:Aerial telescope
332:
331:
327:
326:
325:
323:
322:
321:
307:
306:
305:
295:
293:
283:
281:
271:
269:
257:
247:
245:
237:
235:
230:
229:
223:
209:
205:
192:
191:
187:
182:
167:
165:Further reading
145:
138:
133:
124:
118:
109:
104:
95:
46:
12:
11:
5:
330:
320:
319:
304:
303:
291:
279:
267:
255:
234:
233:External links
231:
228:
227:
221:
203:
184:
183:
181:
178:
177:
176:
166:
163:
162:
161:
156:
151:
144:
141:
140:
139:
134:
127:
125:
119:
112:
110:
105:
98:
94:
91:
45:
42:
9:
6:
4:
3:
2:
329:
318:
315:
314:
312:
302:
292:
290:
280:
278:
268:
266:
261:
256:
254:
244:
243:
240:
224:
222:0-521-48393-X
218:
214:
207:
199:
195:
189:
185:
175:
173:
169:
168:
160:
157:
155:
152:
150:
147:
146:
137:
131:
126:
123:
116:
111:
108:
102:
97:
96:
90:
88:
83:
80:
77:
73:
68:
66:
62:
58:
55:
51:
41:
39:
35:
31:
27:
18:
301:Solar System
212:
206:
197:
188:
171:
84:
81:
69:
54:focal length
47:
25:
23:
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
219:
265:Stars
44:Types
28:is a
217:ISBN
24:An
313::
196:.
89:.
241::
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
