Last Updated 55 minutes ago
Overview
The Type 3471 is the 20 kW Skypan, a single-globe tungsten flood for large scenic backings. At 20 ft the factory chart gives 562.5 fc at centre across a 61.6 ft field with the holder installed.
Key specifications
| Specification | Details |
|---|---|
| Head | Type 3471 Skypan, also catalogued as Skylite |
| Lamp | One 20 kW tungsten globe, mogul bipost |
| Reflector | 52 in. diameter × 23¼ in. deep with skirt |
| Weight | 73 lb with diffuser holder |
| Mount | Removable 1⅛-inch junior pin |
| Nominal colour | 3,200 K with the listed globe at rated voltage |
Replacement lamps
| Lamp code | Power | Lamp voltage | Nominal colour |
|---|---|---|---|
| BCM | 20,000 W | 208 V or 220 V in Mole’s lamp table | 3,200 K |
See the BCM lamp in the lamp lookup.
Mole’s table names BCM in 208 V and 220 V versions. Check the voltage on the actual globe and the head rating plate. The same code appears on lamps with different voltage markings.
Strengths and limitations
The large pan offers broad coverage at long throws. There is one lamp position, so changing the lamp or adding diffusion changes the conditions behind the published table.
Practical uses
For a distant scenic backing, the chart gives 250 fc at 30 ft and 140.6 fc at 40 ft on axis. Compare those readings with the exposure at the ends of the backing and allow for any diffusion added to the frame.
Output and photometrics
Mole identifies the test globe as BCM, with the holder in place. The chart caption says 120 V, which conflicts with the 240 V head rating and both globe voltages in the lamp table. The readings below reproduce the photometric chart. The test voltage is unconfirmed. Field diameter marks the points at approximately half the centre intensity.
| Throw | Centre (fc) | Field diameter |
|---|---|---|
| 5 ft | 9,000 | 15.4 ft |
| 10 ft | 2,250 | 30.8 ft |
| 15 ft | 1,000 | 46.2 ft |
| 20 ft | 562.5 | 61.6 ft |
| 25 ft | 360 | 77 ft |
| 30 ft | 250 | 92.1 ft |
| 35 ft | 183.7 | 107.5 ft |
| 40 ft | 140.6 | 122.9 ft |
| 45 ft | 111.1 | 138.2 ft |
Photometric & exposure calculator
Estimate centre-beam illumination and the corresponding camera aperture from this fixture’s published measurements.
Estimated output
Select a configuration to calculate.
Manufacturer readings are for the stated optic, colour setting and full output, measured at the beam centre. Values between measured distances are interpolated. Point-source values outside those distances are approximate inverse-square estimates; large sources cannot be reliably extrapolated and are limited to their measured range. Exposure uses frame rate, shutter angle, ISO and the selected incident-meter calibration. Only the optics and diffusion explicitly listed in the measurement are included; additional modifiers, bounce, beam edges, ambient light, ND filters and camera exposure-index differences are not accounted for. Confirm critical exposures on set with a meter. Photometric source
Power and controls
Mole publishes a 240 V head rating, 100 A maximum and an MC259G Bates plug. Its archived table repeats 83.3 A for both lower-voltage globes. At rated lamp voltage, 20,000 W corresponds to about 96.2 A at 208 V, 90.9 A at 220 V or 83.3 A at 240 V. These are arithmetic comparisons. The head plate and the individual globe determine the operating configuration.
Optics and mounting
The 24637 skirt and screen accept the four-foot-square 34724 frame. Mole lists a Type 42596 trapeze and a removable 1⅛-inch junior pin. The published 73 lb includes the holder.
Comparable fixtures
The 10 kW Type 2461 has the same reported 52-inch diameter and 73 lb weight with holder. At 30 ft its chart gives 105 fc on axis, compared with 250 fc here.
Field coverage
Mole’s rental list identifies the 20 kW as Type 3471 and lists a holder, frame, scrims, safety screen and cable with the head. Mole-Richardson rental catalogue.
Rental and used-fixture checks
Request the head and globe voltage markings and the connector designation when reserving the unit. The conflicting figures in the archived data sheet make the equipment markings especially important on this model.
Documentation
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