The following table has been taken partly from the original
NIRC2 proposal by Keith Matthews and Tom Soifer, and partly from
information on the as-built instrument.
The original detector electronics based
on inMOS
transputers was replaced with
an STA Archon
controller in 2023, but the detector is still the
original Aladdin III InSb 1024x1024 array. Science operations
with the Archon controller started on Nov 20, 2023. The
table below includes detector electronics performance provided
for both, transputers and Archon.
| Input f/ ratio |
f/15 |
| Wavelength range |
0.9-5.3 microns |
|
Field of view
|
-
Narrow camera: 10x10 arcsec
-
Medium camera: 20x20 arcsec
-
Wide camera: 40x40 arcsec
|
|
Pixel scale
|
-
Narrow camera: 0.009942 arcsec/pixel
(+/- 0.00005")
-
Medium camera: 0.019829 arcsec/pixel
-
Wide camera: 0.039686 arcsec/pixel
|
|
Filters
|
z, Y, J, H, K, Ks, Kp, Lw, Lp, Ms, HeI, Pa_gamma, Jcont,
Pa_beta, H_cont, CH4S, H2, Fe II, CH4L, Br_gamma, Kcont,
CO, H2O, PAH, Br_alpha, Br_alpha_cont
|
|
Pupil masks
|
-
1 circular fixed, circumscribes the telescope pupil.
-
1 hexagonal fixed, inscribes the telescope pupil and
masks spiders. Needs to be used in vertical angle
mode, i.e. telescope following pupil.
-
1 circular rotating, inscribes the telescope pupil and
masks the spiders.
-
3 hexagonal, rotating.
|
|
Slits
|
Slit widths: 10, 20, 30, 40, 60, 80, 120, and 160 milliarcsec
|
|
Coronagraphy
|
-
Circular Lyot stops: 100, 150, 200, 300, 400, 600, 800,
1000, 1500, 2000 milliarcsec
-
Vortex coronagraphs: L/M-band optimized (vortexlm),
K-band optimized (vortexk)
|
|
Grisms
|
-
Low resolution (lowres): Resolving power per pixel in
K with the narrow camera: 10,200
-
Medium resolution (medres): Resolving power per pixel
in K with the narrow camera: 17,300
|
|
Detector
|
-
1024x1024 InSb Aladdin-III array, 27 micron pixels
-
32 simultaneous outputs, grouped in 8 pixels across a
row in each of 4 quadrants
-
Subarray capability down to 32x120 pix
-
Nominal operating temperature: 29 K
-
Gain:
-
Prior to Nov 20, 2023 (transputers): 4 e-/DN
-
Nov 20, 2023 and after (Archon): 8 e-/DN
|
|
Detector readout modes
|
-
Single (sampmode 1): Single read. Used for
engineering purposes.
-
CDS (sampmode 2): Correlated Double
Sampling. One read pair. Normally used for bright
targets and/or high background conditions that require
the minimum integration time for a give sub-array
size.
-
MCDS (sampmode 3 N): Multiple Correlated
Double Sampling. Multiple read pairs (N is
the number of read pairs). Used for faint targets
and/or low background conditions. The readnoise
decreases approximately as 1 over the square root of
the number of read pairs.
-
UTR (sampmode 4 N): Sampling Up The
Ramp. Experimental mode available with the Archon
controller after November 20, 2023. N is
the number of samples up the ramp.
|
|
Minimum frame time
|
-
Prior to Nov 20, 2023 (transputers): 0.182 sec, full
frame in CDS mode
-
Nov 20, 2023 and after (Archon): 0.170 sec, full frame
in CDS mode
|
|
Read noise
|
-
Prior to Nov 20, 2023 (transputers):
-
CDS (sampmode 2): ~45 – 50 e-
-
MCDS with 16 read pairs (sampmode 3 16): ~15 e-
-
Nov 20, 2023 and after (Archon):
-
CDS (sampmode 2): ~45 – 50 e-
-
MCDS with 16 read pairs (sampmode 3 16): ~15 e-
|
|
Dark current
|
< 0.1 electrons/pixel/sec
|
|
QE
|
80% at 1.7 microns
|
|
Well depth
|
-
Prior to Nov 20, 2023 (transputers): ~9,000 DN at ~1%
linearity
-
Nov 20, 2023 and after (Archon): ~4,500 DN at ~1%
linearity
|
|