LSST Camera Filter Status

SDSSSDSSBand-pass TransitionBand-pass Transition

Half Maximum Transmission Half Maximum Transmission Wavelength (nm)Wavelength (nm)

g r i z g r i z Blue side Blue side 402 552 693 840 402 552 693 840

Red side Red side 548 693 851 -548 693 851 -

LSSTLSSTBand-pass TransitionBand-pass Transition

Half Maximum Transmission Half Maximum Transmission Wavelength (nm)Wavelength (nm)

u g r i z u g r i z y1 y2 y3 y1 y2 y3 Blue side Blue side 330330 400 552 691 818 400 552 691 818 960 970 970960 970 970 Red side Red side 400 552 691 818 922 400 552 691 818 922 1030 1020 10501030 1020 1050

G-Balmer break @400. OI line@ 557R-matches SDSSI-red side short of sky emission @826Z-red side stop before H2O bandsY–options detailed

Optical Design: Filter Reference Design

* Filter band-pass characteristics are defined based on a combination of scientific considerations

Half-Maximum Transmission WavelengthBlue Side

Red Side

Comments

U 330 400 Blue side cut-off depends on AR coatingG 400 552 Balmer break at 400 nmR 552 691 Matches SDSSI 691 818 Red side short of sky emission at 826 nmZ 818 922 Red side stop before H2O bandsY 930 1070 Red cut-off before detector cut-off

LSST Ideal Filters

0.0

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Wavelength (nm)

Tra

nsm

issio

n

u g r i z Y

• 75 cm dia.• Curved surface• Filter is concentric about Filter is concentric about the chief ray so that all portionsthe chief ray so that all portions of the filter see the same of the filter see the same angle of incidence range, angle of incidence range, 14.2º to 23.6º14.2º to 23.6º

Uniform depositionrequired at 1% levelover entire filter

LSST Ideal Filters

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20.0

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300 400 500 600 700 800 900 1000 1100 1200

Wavelength (nm)

Transmission

u g r i z Y

LSST Filter Set

300cm coating chamber

NOVA Laser Fusion Optics

* Discussions initiated with multiple vendors

– JDS Uniphase

– Infinite Optics

– SAGEM

– Barr

– Goodrich

– Asahi Spectra

* Substantial industrial base exists to coat large, thin filters

* Industry estimates of cost and schedule to coat these large, thin optics have been used as input for LSST camera optics schedule and budget

– These estimates include a risk reduction study during the R&D phase

Filter prototype RFP going out to vendors

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Leak Update

Orig Design

Updated Design

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Y-Band Options (Y2, Y3 and Y4)