Basic Optical Data
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| Primary Mirror |
| Radius of curvature |
|
21318.0 mm concave |
| Conic constant |
|
-1.09763 |
| Mirror diameter |
|
4011.6 mm (Drawing 2106-E1) |
| Bare mirror clear aperture |
|
diam 4002.6 mm |
| Central hole |
|
diam 1324 mm |
| Used clear aperture |
|
diam 3797 mm (Measured by Phil Massey) |
| Central obscuration |
|
diam 1651 mm (PF cage) |
| Central obscuration |
|
diam 1800 mm (DESI cage) |
| Light-collecting area |
|
9.182 m² |
| Light-collecting area |
|
8.658 m² (DESI) |
| PF Mosaic Focus Calibration |
|
1.043 microns/unit |
|
| F/7.8 Secondary Mirror |
| Distance from primary |
|
7492.0 mm |
| Radius of curvature |
|
9643.0 mm convex |
| Conic constant |
|
-5.2951 |
| Clear aperture |
|
diam 1191.6 mm (CHECK) |
| Secondary to RC focus |
|
9306.2 mm |
| Instrument rotator to RC focus |
|
152.4 mm |
| Effective focal length |
|
31258.7 mm |
| Focus Calibration |
|
0.991 microns/unit |
- Download 4-m f/7.6 ZEMAX file
|
|
| F/15 Secondary Mirror |
| Distance from primary |
|
8634.5 mm |
| Radius of curvature |
|
5000.2 mm convex |
| Conic constant |
|
-3.09014 |
| Clear aperture |
|
742.7 mm |
| Secondary to SQIID focus |
|
10895 mm |
| Instrument rotator to SQIID focus |
|
598.7 mm |
| Effective focal length |
|
57160.3 mm |
- Download 4-m f/15 ZEMAX file
|
Prime Focus (f/3.1) Corrector and ADC Prisms
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| Opto-Mechanical Assembly - 4 Meter Prime Focus Corrector |
 |
| The 4-m prime focus corrector is described in Jacoby, Liang, Vaughnn, Reed, and Armandroff
(1988 SPIE, 3355, 721).
|
Slew Time
-
 |
| Calculated slew and servo settling time for the
4-meter telescope with the new Mayall Active Primary Support (MAPS)
implementation. Slew motion occurs in both HA and DEC simultaneously, so the
time estimate should use the longer of the two motions.
|
South East Annex Position
-
The position of the telescope when at the South East Annex is:
Hour Angle = 3:44:40 E. and Declination = 31:36:00 S.
|
4MAPS - 4 Meter Active Primary System
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4MAPS Manual (NOAO only)
Risley Prisms - Cass Focus
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| Risley Prisms |
Deployable |
| Clear Aperture |
172 mm |
| Total Thickness |
104 mm |
| Front Element to R-C Focus |
931 mm |
| Clear Field f/7.8 |
45.3 mm = 298 arcsec |
Telescope
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Cassegrain Cage Mechanical Data
* datum=back of primary mirror cell
| Component | Weight(lb) | Moment (in-lb)* |
| Instrument rotator |
960 |
6720 |
| Guider |
640 |
11520 |
| Allowable instrument |
1350 |
|
| Total load |
2950 |
72570 |
additional weight information
| Optical Layout Figure | Automatic Guider Bolt Pattern |
|
|
| Cassegrain Cage Clearances | Cassegrain Instrument Rotator |
|
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| Cassegrain Guider Assembly | |
|
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Dome
-
There are some old (and old-fashioned paper) enormous drawings of the dome and environment, but they are like ancient papyrus and very crowded with information.
| Building Information | |
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