Wheel Specifications

PHARO contains 4 wheels that carry slits, pupil masks, filters, and grisms. The elements currently installed in each wheel are listed in the following tables. Updated 08/09/2011 C. Heffner.

Slit Wheel
# Name Comment
1 0.41" Spot coronograph mode
2 0.13" Slit spectrograph mode
3 0.91" Spot coronograph mode
4 0.26" Slit spectrograph mode
5 K band Vortex Mask G. Serabyn
6 0.52" Slit spectrograph mode
7 40" Field maskimaging mode
8 Radial BL Mask J. Crepp
9 25" Field maskimaging mode
10 H band Vortex Mask G. Serabyn
Lyot Wheel
# Name Comment
1Block .
2Open .
3Std Cross .
4FQPM Pupil G. Serabyn
5Med Cross .
6Big Cross .
79 Hole Pin Mask J. Lloyd
8Linear Pupil J. Lloyd
918 Hole Pin Mask J. Lloyd
10Binary Pupil J. Carson

Filter Wheel
# Filter Central
Wavelength*
(microns) 		Bandpass
(microns) 		Half Power
Wavelengths*
(microns) 		TransmissionSensitivity Manufacturer
1 Open .. . .. .
2 J 1.2460.162 1.165 - 1.327 87.3%. OCLI
3 H 1.6350.296 1.487 - 1.783 84.9%. OCLI
4 K 2.1960.336 2.028 - 2.36490.4%. OCLI
5 K S 2.145 0.310 1.990 - 2.300 91.8%. OCLI
6 Methane Short 1.5700.100 1.520 - 1.620  . NDC
7 Methane Long 1.6900.100 1.640 - 1.740  . NDC
8 Br Gamma 2.180.03 2.165 - 2.195  . NDC
9 - - - - - . -
10Kcont 2.290.035 2.272 - 2.307  . NDC
*Note: Wavelength measurements for OCLI filters were made at room temperature, not at operating temperature (77 Kelvin). Wavelengths of narrow-band Barr filters estimated from room temperature measurements shifted to wavelength of line.


Grism Wheel
# Filter Central
Wavelength*
(microns) 		Bandpass
(microns) 		5% Power
Wavelengths*
(microns) 		TransmissionSensitivity Manufacturer
1 ND 1% . . . 1% . JANOS
2H Grism See table below for specs on Grisms
3 Open . . . . . .
4K Grism See table below for specs on Grisms
5Fe II 1.648 0.025 1.638 - 1.662 . . NDC
6 H Continuum 1.668 0.018 1.651 - 1.669 . . NDC
7 H & K Grism + Blocking Filter . . . . . G. Serabyn
8 H2 2.124 0.007 2.121 - 2.128 80.1% . Barr
9 J Grism See table below for specs on Grisms
10ND 0.1% . . . 0.1% . JANOS
*Note: Wavelength measurements for Barr filters made at room temperature, not at operating temperature (77 Kelvin).

.
Grisms
# Filter Wavelength
Range*
(microns) 		Dispersion
(nm/pixel) 		Comment
2 H Grism 1.49 - 1.78 0.28467 .
4 K Grism 2.03 - 2.37 0.33215 .
7 H&K Grism 1.49 - 2.37 ? G.Serabyn
9 J Grism 1.17 - 1.33 0.15771 .

For more information about specific manufacturers, visit the OCLI , JANOS , and BARR home pages.