17:
50:
than a conventional magnifying glass, typically 10× up to 20×. Most single lens magnifiers are limited to 5× or so before significant distortion occurs. The drawback is that the diaphragm groove reduces the area seen through the magnifier.
63:
introduced a much improved version of the earliest magnifiers consisting of a spherical glass by employing two hemispheres of glass mounted together with a small stop between them.
75:
brought the
Wollaston–Brewster lens into general notice and further refined the design by modifying the shape of the groove, though Coddington laid no claim to being its inventor.
67:
found that
Wollaston's form worked best when the two lenses were hemispheres and the central space was filled up with a transparent cement having the same
103:
38:
71:
as the glass. He therefore used a sphere from a single piece of glass with a deep groove cut in it. In 1829,
60:
43:
152:
64:
72:
68:
29:
157:
20:
The cross-section through the optical axis shows the grooves that limit the aberration.
146:
84:
47:
33:
16:
117:
135:
42:, thus limiting the rays to those close to the axis, which minimizes
15:
108:, L. C. Martin, Sir Isaac Pitman & Sons, Ltd, London, 1932.
8:
105:An Introduction To Applied Optics, Volume II
36:with a central deep groove diaphragm at the
96:
7:
32:consisting of a single very thick
14:
122:, Williams, Book 4, chapter V.
1:
174:
46:. This allows for greater
61:William Hyde Wollaston
21:
19:
44:spherical aberration
26:Coddington magnifier
137:Build a Coddington
119:History of Science
65:Sir David Brewster
22:
165:
123:
115:
109:
101:
73:Henry Coddington
69:refractive index
30:magnifying glass
173:
172:
168:
167:
166:
164:
163:
162:
143:
142:
132:
127:
126:
116:
112:
102:
98:
93:
81:
57:
12:
11:
5:
171:
169:
161:
160:
155:
145:
144:
141:
140:
131:
130:External links
128:
125:
124:
110:
95:
94:
92:
89:
88:
87:
80:
77:
56:
53:
13:
10:
9:
6:
4:
3:
2:
170:
159:
156:
154:
151:
150:
148:
139:
138:
134:
133:
129:
121:
120:
114:
111:
107:
106:
100:
97:
90:
86:
85:Stanhope lens
83:
82:
78:
76:
74:
70:
66:
62:
54:
52:
49:
48:magnification
45:
41:
40:
35:
31:
27:
18:
136:
118:
113:
104:
99:
58:
37:
25:
23:
153:Magnifiers
147:Categories
91:References
79:See also
59:In 1812
55:History
39:equator
158:Lenses
28:is a
34:lens
149::
24:A
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
