Array Type:
Rockwell 1024 x 1024 pixel HgCdTe HAWAII array [Rockwell]
Pixel size:
18.5um
Geometric data:
Wavelength range:
Detector: 0.8 um - 2.5 um (CIRSI, phase 1 will not work beyond 1.9um)
Quantum efficiency:
60% at 1.0um, 60% at 0.8 um
[QE curve(provided by Rockwell)]
Operational Temperature:
Filters: Available and planned Filter Set
CIRSI+PATT Telescopes: Image scale and field of view
Telescope and Focus | Diameter (m) | um/" | "/pixel | fov (single array) |
Contiguous field for 4 exposures |
Exposures per degree |
Survey Power |
---|---|---|---|---|---|---|---|
WHT Prime f/2.8 |
4.2m | 57.0 | 0.32 | 5.5' x 5.5' | 20.9' x 20.9' | 30.9 | 0.42 |
INT Prime f/3.3 |
2.5m | 40.486 | 0.457 | 7.80' x 7.80' | 29.64' x 29.64' | 16.4 | 0.29 |
AAT Prime f/3.3 |
3.9m | 63.5 | 0.29 | 4.9' x 4.9' | 18.6' x 18.6' | 39.4 | 0.28 |
Other Telescope NIR camera combinations:
Telescope and Focus | - | - | "/pixel | fov (single array) |
Exposures per degree |
Survey Power |
---|---|---|---|---|---|---|
Keck 10.0m Cass | NIRC | InSb 256x256 | 0.15 | 0.64'x 0.64' | 8800 | 0.0089 |
VLT 8.2m Cass | ISAAC | MCT 1024x1024 | 0.15 | 2.5'x 2.5' | 576 | 0.09 |
WHT 4.2m Cass f/11 | INGRID | MCT 1024x1024 | 0.25 | 4.27' x 4.27' | 197 | 0.07 |
WHT 4.2m Nas f/11 | WHIRCAM | InSb 256x256 | 0.24 | 1.02' x 1.02' | 3400 | 0.0040 |
UKIRT
3.9m Cass f/? |
IRCAM3 | InSb 256x256 | 0.29 | 1.22' x 1.22' | 2400 | 0.0027 |
UKIRT 3.9m Cass f/? |
UFTI | MCT 1024x1024 | 0.09 | 1.54' x 1.54 ' | 1526 | 0.0043 |
CFHT 3.6m Cass | QUIRC | MCT 1024x1024 | 0.15 | 2.56'x2.56' | 550 | 0.0185 |
ESO NTT | SOFI | MCT 1024x1024 | 0.14 | 2.9' x 2.9' | 428 | 0.02 |
HST 2.4m Cass | NICMOS | MCT 256x256 | 0.04-0.20 | - | - | - |
The Gemini project has produced a list of
[
filters and specifications ]
for IR filters. The Gemini J filter is of interest since it is
narrow than the standard J cutting out more of the OH absorption features.
As a result the sky background is reduced. The potential gain needs
to be investigated since the photon rate from the objects of interest
is reduced.
Filter | Central wavelenth or Bandpass (um) |
FWHM (um or %) |
Transmission Peak (%) |
Comment |
---|---|---|---|---|
Z | 0.92 | 0.14 | 75 | - |
J | 1.25 | 0.28 | 75 | - |
H | 1.65 | 0.30 | 75 | - |
K | 1.95-?.?? | - | - | red cut will depend on background |
HeI | 1.083 | 1% | 75 | depends on interest |
Pa-gamma | 1.094 | 1% | 75 | depends on interest |
OII | 1.237 | 1% | 75 | depends on interest |
Pa-beta | 1.282 | 1% | 75 | depends on interest |
FeII | 1.644 | 1% | 75 | depends on interest |
NB-J | 1.25 | 1% | 75 | survey |
NB-H | 1.64 | 1% | 75 | survey |
Below we tabulated the sensitivity of various camera systems in
terms of the measured photon rate in electrons per second. Note
that one actually measures Analogue to Digigal Units(ADUs) or
counts. The units are
Billions of electrons/second from zeroth magnitude object or 1000 of
electrons/second for a 15th magnitude star. Taking the value at 15th
magnitude is convenent for J and H since this is then detected
count rate from the sky. When computing the count/rate per pixel
do not forget to include the conversion from magnitudes/arc sec^2
to magnitudes/pixel.
Use the Exposure Time Calculator which is available
here
Sky Brightness
Note in J and H the sky is predominantly due to OH lines and
factors of 3 variations in a single night are not uncommon in H,
so that values below should not be necessarily interpreted to mean a particular
site OR instrument is worse than another.
Telescope
Instrument
J
H
Ks
K
reference
CFHT
RedEye
16.0
14.5
-
13.2
CFHT Redeye manual
UoH 88'
-
16.1
14.4
-
13.3
CFHT Redeye manual
Palomar 60'
-
15.8
14.1
13.6
-
Murphy et al, PASP, 107, 1234 1995
OCIW 100'
-
15.9
14.0
11.8
-
Persson et al, PASP, 104, 204 1992
WHT
WHIRCAM
15.6
13.9
-
-
Shaun Hughes, priv comm (Feb 97)
Calar Alto 3.5m
MAGIC
16.0
13.9
13.0
12.2
WWW
Calar Alto 3.5m
OMEGA
15.1
13.1
12.7
11.9
WWW
ESO 2.2m
IRAC-2
15.0-16.5
12.8-14.3
12.0-13.5
11.2-13.0
WWW
ESO 3.5m NTT
SOFI
16.0
14.3
13.0
-
WWW
CTIO 3.95m
CCOB
14.6
13.6
12.6
11.9
WWW
Sensitivity
Telescope
Instrument
J
H
Ks
K
reference
Calar Alto 3.5m
MAGIC
8.2
7.7
5.8
5.3
WWW
Calar Alto 3.5m
OMEGA
12.7
9.4
10.1
9.4
WWW
CTIO 3.95m
CCOB
3.6
3.8
2.5
2.9
WWW
CIRSI Sensitivity:
Effective Wavelengths and Zero-points for Photometric Bands
1 Jy= 10**-23 ergs cm-2 Hz-1 = 10**-26 W m-2 Hz-1
1 Jansky (Jy) is defined as 10-26Wm-2Hz-1
Band
Lambda
DLambda
NICMOS handbook
-
-
-
-
-
-
-
-
Fo[Jy]
(CIT)
Fo[Jy]
(UKIRT)
Beckwith
(1976)
Wamsteker
(198n)
Koornneef
(198n)
Campins et al
(1985)
Bessell and Brett
(1988)
van def Bliek et al(1996)
adopted
AB
V
0.55
0.80
3540
3540
-
-
-
-
3600
-
3540
0.03
z
0.92
0.15
-
-
-
-
-
-
-
-
2190
0.55
J
1.25
0.25
1670
1600
-
1650
1635
1622
1570
1680
1625
0.88
H
1.65
0.30
980
1020
980
1070
1090
1055
1020
1070
1040
1.36
K
2.2
0.4
620
657
620
673
665
65
636
664
650
1.87
L
3.4
-
280
290
280
269
277
283
281
-
288
-
L'
3.74
-
-
252
-
-
-
-
235
260
250
-
M
4.8
-
150
163
150
158
164
167
154
167
160
-
N
10.1
-
37
39
37
-
-
-
-
43.5
-
-
Q
20.0
-
10
10
10
-
-
-
-
12.3
-
-
2 AB=-2.5log(Fnu) -48.60
3 Note that whilst Vega is defined has having zero colour in the Vega based magnitude system it has a magnitude of V=0.03 for the above normalisation