File:EB1911 Vision - Visual Angle.jpg
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EB1911_Vision_-_Visual_Angle.jpg (549 × 485 pixels, file size: 83 KB, MIME type: image/jpeg)
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Summary
| Description |
English: To understand the formation of an image on the retina, suppose a line drawn from each of its two extremities to the nodal point and continued onwards to the retina, as in the figure, where the visual angle is x. It is evident that its size will depend on the size of the object and the distance of the object from the eye. Thus, also, objects of different sizes, c, d, e in fig. 6, may be included in the same visual angle, as they are at different distances from the eye. The size of the retinal image may be calculated if we know the size of the object, its distance from the nodal point o, and the distance of the nodal point from the posterior focus. Let A be the size of the object, B its distance from the nodal point, and C the distance of o from the retina, or 15 mm.; then the size of the retinal image x = (A + 15)/B. |
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| Date | published 1911 | |||
| Source | “Vision,” Encyclopædia Britannica (11th ed.), v. 28, 1911, p. 132, fig. 6. | |||
| Author | Unknown artist | |||
| Permission (Reusing this file) |
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File history
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 23:09, 28 August 2021 | | 549 × 485 (83 KB) | Bob Burkhardt | {{Information |description = {{en|1=To understand the formation of an image on the retina, suppose a line drawn from each of its two extremities to the nodal point and continued onwards to the retina, as in fig. 6, where the visual angle is ''x''. It is evident that its size will depend on the size of the object and the distance of the object from the eye. Thus, also, objects of different sizes, ''c'', ''d'', ''e'' in fig. 6, may be included in the same visual angle, as they are at different... |
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