Image:RitcheyTelescope.JPG
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Ritchey 24" reflective telescope
This picture was taken in July 2004 from an exhibition at Chabot Space & Science Center in Oakland, California.
The caption of the exhibit said:
Ritchey 24-inch Reflecting Telescope
By George W. Ritchey, American Telescope Maker
On loan from Smithsonian Institution
George Willis Ritchey (1864-1945) was the builder of the first successful large American reflecting telescopes. A telescope designer who perfected the methods for making astronomical mirrors and a master at celestial photography, George Ritchey worked closely with George Ellery Hale, the phenomenal fund-raiser and organizer of observatories. Mount Wilson Observatory with its 60-inch and 100-inch reflector telescopes stands today as a monument ot their collaboration.
The first important telescope built by George Ritchey (at Yerkes Observatiory in Wisconsin) was the 24-inch reflector you see here. He made the primary mirror (an f/4 paraboloid) in his shop and Francis G. Pease worked on the cassegrain secondary mirror. Ritchey later photographed many nebulae with this telescope. The pictures were the first opportunity astronomers had to see the true forms and complicated structure of nebulae like the Orion Nebula. But more importantly, the photographs convinced astronomers that reflectors would be the large telescopes on which future research would be based. This 24-inch telescope's mirror became the prototype for the 60-inch and 100-inch mirrors that Ritchey would later make for the Mount Wilson Observatory near Pasadena, California.
The telescope is on a German equatorial mount. The mirror is silvered glass 23.5 inches wide by 2 and 5/8 inches thick. The bottom of the mirror is supported at three pointes and at the edge. The skeleton tube, 7 feet long, held the secondary mirror and photographic accessories. The eyepiece position has an elaborate stage (brass) with a 2 and 1/8 inch threaded opening. The entire stage can be rotated as well as moved precisedly in either axis.
The holder is designed for use with a photographic plate. The drive mechanism (in the .... <the rest of the text were hidden from view>
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File history
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| Date/Time | Dimensions | User | Comment | |
|---|---|---|---|---|
| current | 20:33, 15 July 2004 | 623×480 (161 KB) | Kowloonese (Talk | contribs) | (Ritchey 24" reflective telescope) |
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| Camera manufacturer | SONY |
|---|---|
| Camera model | CYBERSHOT |
| Exposure time | 1/40 sec (0.025) |
| F-number | f/2.8 |
| Date and time of data generation | 14:10, 10 July 2004 |
| Lens focal length | 8 mm |
| Horizontal resolution | 72 dpi |
| Vertical resolution | 72 dpi |
| File change date and time | 14:10, 10 July 2004 |
| Y and C positioning | 2 |
| Exposure Program | Normal program |
| ISO speed rating | 100 |
| Exif version | 2.2 |
| Date and time of digitizing | 14:10, 10 July 2004 |
| Exposure bias | 0 |
| Maximum land aperture | 3 |
| Metering mode | Pattern |
| Light source | Unknown |
| Flash | 0 |
| Color space | sRGB |
| Custom image processing | Normal process |
| Exposure mode | Auto exposure |
| White balance | Auto white balance |
| Scene capture type | Standard |
