2003-03-21 PalSpec Status Review 1

PalSpec Status Review

WITH NOTES RE KECK APPLICATION

Terry Herter, Chuck Henderson (Cornell)John Wilson, Mike Skrutskie (Univ. or Virginia)Keith Matthews (Caltech), Jim Howard (Telic)

March 21, 2003

2003-03-21 PalSpec Status Review 2

Spectrograph Requirements

• Original Baseline– Simultaneous coverage from 0.80 – 2.5 m

• Emphasis on J, H, and K bands

– R ~ 2500 with 30 x 0.9 arcsec slit– For keck R~2500 with slit ~ 15 x 0.45 arcsec– Slit viewer with > 2x2 arcmin2 FoV– Keck slit viewer ~ 40”x40”

• Delivery– December 2003– For Keck, delivery TBD

2003-03-21 PalSpec Status Review 3

WHY DOES IT WORK ON KECK

• Instrument is being designed to study faint, small (<~1”) objects, one at a time

• f number: at palomar 16, keck 16.6• Seeing at keck ~1/2 that at Palomar

– =>palomar instrument will work at keck with fov reduced by factor of 2

2003-03-21 PalSpec Status Review 4

OH Line Positions

Positions of atmosphere airglow (OH) lines vs. wavelength overlaid with atmospheric transmission.

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6

Wavelength (um)

Rel

ativ

e In

t. (

phot

ons)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Atm

osph

eric

Tra

nsm

issi

on

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Perspective Views

Collimator

Reimager

Grating

Slit viewer

Focal Plane

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Perspective Views

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View with Shell

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6 inches

CaF2/CaF2 Infrasil/ZnS/ZnSe ZnSe/ZnSe

Asphere

Asphere

Array tilted

1.3 deg

Prototype Camera by Jim Howard, Telic Optics

Prototype Spectrograph Camera

2003-03-21 PalSpec Status Review 9

Top/Bottom of

30 arcsec slit

Camera Spot Diagrams

2003-03-21 PalSpec Status Review 10

2 pix radius = 18 micron

If 2.78 pix/arcsec (slit width direction):

@ Palomar = 72 arcsec

@ Keck = 36 arcsec

Encircled Energy

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Spectrum Layout in

Focal Plane

Possible array rotation (also rotate slit to keep on columns)

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Spectral Resolution

Spectral resolution for 1.0 arcsec slit with 2.78 pixels/arcsecond.

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Grating Efficiency

2003-03-21 PalSpec Status Review 14

* includes primary through detector

System Throughput

Atmospheric transmission

Off the array

2003-03-21 PalSpec Status Review 15

Slit Viewer• Design Specs

– Operates at Ks– Images to ~ 0.14 arcsec/pix– Giving 2.4 arcmin FoV => 5.7 sq. arcmin

IntegrationTime (sec)

Ks mag(S/N = 5)

Number of Galaxies

Number of Stars

1 17.2 3 1

10 18.4 15 1

30 19.0 27 1

2003-03-21 PalSpec Status Review 16

KECK SLIT VIEWER

• WE’LL USE 256X256 ARRAY FROM EXISTING IR INSTRUMENT

• FOV EQUIVALENT TO NIRC FOV (40”)

2003-03-21 PalSpec Status Review 17

Slit Viewer Detection Rate

Slit viewer with 2.4 arcmin FoVCounts from Glazebrook et al. 1994, MNRAS, 266, 65.

0.01

0.1

1

10

100

1000

10 12 14 16 18 20 22 24

K-magnitude

# o

f O

bje

cts

in F

oV

Galaxies

Stars

1 sec

10 sec

30 sec

2003-03-21 PalSpec Status Review 18

Spectrograph Line Sensitivity

• Assumptions– S/N = 5, 10 pixels to extract line– System throughput = 0.15 in all bands– Between OH-lines (J,H,K bkgnd = 70, 200, 70 Jy/arcsec2)– RN = 5 e-, i(dark) = 0.01 e-/sec

• KECK SHOULD BE 4x BETTER

Flux (10-17 ergs/cm2/s) tback

Band 600 sec 1800 sec 3600 sec (sec)

J 2.1 1.1 0.75 410

H 2.2 1.2 0.87 170

K 3.0 1.7 1.2 57

tback = integration time for RN to contribute < 20% to noise.

2003-03-21 PalSpec Status Review 19

Spectrograph Continuum Sensitivity

• Assumptions– S/N = 5 per resolution element– System throughput = 0.15 in all bands– Between OH-lines (J,H,K bkgnd = 70, 200, 70 Jy/arcsec2)– RN = 5 e-, i(dark) = 0.01 e-/sec

• KECK WILL BE 1.5 MAG DEEPER FOR POINT SOURCES

Mag in 1 resolution element

Band 600 sec 1800 sec 3600 sec

J 19.7 20.4 20.8

H 18.8 19.5 19.8

K 17.7 18.3 18.7

2003-03-21 PalSpec Status Review 20

Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 May-03 Jun-03 Jul-03 Aug-03 Sep-03 Oct-03 Nov-03 Dec-03

Spectrographpre-preliminary design

strawman designfinal design

camera prelim designcamera design

camera fab

collimator designcollimator fab

grating fabprism fab

Slit viewerrequirements

preliminary designfinal designcamera fab

Cryostatbrainstormingrough design

final designfab

Electronicsharnesses (2)

layoutmanufacture

integ. and testmisc. dewar wiring

Array control/readoutPC board clones

PC board assemblybox fab (clone)integ. and test

Palomar Spectrograph Development Schedule

2003-03-21 PalSpec Status Review 21

WIRC-2K PC boardJPL array delivery

requirementsdesign

programming mods

requirementsdesignbuild 0build 1

requirementsdesignbuild 0build 1

lab I&Tobserving I&T

Handling cartdesign

fab

Telescope mountscope requirements

preliminary designfinal design

fab

IntegrationTest

First science light

Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 May-03 Jun-03 Jul-03 Aug-03 Sep-03 Oct-03 Nov-03 Dec-03Palomar Spectrograph Development Schedule