Low-resolution Spectroscopy
Single Raw Frame
|
Single Order, Low-resolution |
|
|
|
|
|
|
count rates (ADU/s/coadd) |
| Filter |
source |
mag. |
slit (") |
seeing (") |
λ |
source |
bkg |
sky lines |
| NIRSPEC-1 |
HIP 30762 |
J=6.55 |
0.76 x 42 |
˜0.7 |
1.04μm |
4820 |
<1 |
<1 |
| NIRSPEC-3 |
HD 332937 |
J=8.66 |
0.76 x 42 |
˜0.85 |
1.21μm |
792 |
<1 |
7 |
| NIRSPEC-5 |
HIP 55051 |
H=8.04 |
0.76 x 42 |
˜0.5 |
1.61μm |
706 |
<1 |
19 |
| NIRSPEC-7 |
HD 107655 |
K=6.17 |
0.76 x 42 |
˜0.9 |
2.16μm |
1433 |
<1 |
13 |
| KL |
HD 9986 |
L=5.15 |
0.76 x 42 |
˜0.5 |
3.59μm |
8400 |
3130 |
6000 |
Notes
- seeing estimated from FWHM across spectral trace (spatial pixels lie along rows in low res. images: 0.144 "/pixel)
- source count rates are peak
- sky line count rates are peak
- L mag. estimated from Spectral Type and published V mag
Reduced Spectra (sky subtracted, flatfielded, extracted)
|
Single Order, Low-resolution |
| Filter |
source |
mag. |
itime(sec) x coadd x frames |
slit (") |
seeing (") |
λ |
measured SNR/pix |
Mag. for SNR=100 in 1hr |
| NIRSPEC-1 |
HIP 30762 |
J=6.55 |
0.5 x 1 x 1 |
0.76 x 42 |
˜0.7 |
1.04μm |
80 |
J=15.7 |
| NIRSPEC-3 |
HD 332937 |
J=8.66 |
2 x 6 x 1 |
0.76 x 42 |
˜0.85 |
1.21μm |
85 |
J=14.5 |
| NIRSPEC-5 |
HIP 55051 |
H=8.04 |
5 x 2 x 1 |
0.76 x 42 |
˜0.5 |
1.61μm |
190 |
H=15.8 |
| NIRSPEC-7 |
HD 107655 |
K=6.17 |
3 x 1 x 1 |
0.76 x 42 |
˜0.9 |
2.16μm |
70 |
K=13.1 |
| KL |
HD 9986 |
L=5.15 |
1 x 10 x 1 |
0.76 x 42 |
˜0.5 |
3.59μm |
80 |
L=11.0 |
Notes
- Values are based on observations of a point source subject to slit losses
- Magnitude equivalent to reach SNR=100 in 1 hour assumes noise is
dominated by source or sky background
High-resolution Spectroscopy
Single Raw Frame
|
Cross-dispersed, High-resolution |
|
|
|
|
|
|
count rates (ADU/s/coadd) |
| Filter |
source |
mag. |
slit (") |
seeing (") |
λ + order |
source |
bkg |
sky lines |
| NIRSPEC-3 |
HD 1561 |
J=6.33 |
0.432 x 12 |
˜0.5 |
1.213μm m=63 |
254 |
<1 |
4 |
|
|
|
|
|
1.286μm m=59 |
259 |
<1 |
6 |
| NIRSPEC-5 |
HD 1561 |
H=6.38 |
0.432 x 12 |
˜0.5 |
1.555μm m=49 |
407 |
<1 |
3 |
|
|
|
|
|
1.692μm m=45 |
300 |
<1 |
5 |
| NIRSPEC-7 |
HR 3067 |
K=4.66 |
0.576 x 12 |
˜0.5 |
2.105μm m=36 |
1312 |
<1 |
6 |
|
|
|
|
|
2.290μm m=33 |
925 |
<1 |
n/a |
| KL |
HR 1552 |
L=3.8 |
0.432 x 24 |
˜0.4 |
3.017μm m=25 |
992 |
13 |
60 |
|
|
|
|
|
3.274μm m=23 |
1043 |
38 |
208 |
|
|
|
|
|
3.767μm m=20 |
1022 |
162 |
207 |
| M-wide |
HR 1412 |
M=2.8 |
0.432 x 24 |
˜0.4 |
4.648μm m=16 |
2070 |
1270 |
6000 |
|
|
|
|
|
4.958μm m=15 |
2900 |
2140 |
11,700 |
Notes
- seeing estimated from FWHM across spectral trace (spatial pixels lie along columns in high res. images: 0.193 "/pixel)
- source count rates are peak
- sky line count rates are peak in given order
- L and M band magnitudes are estimated from SED fit to opt. and NIR colors
Reduced Spectra (sky subtracted, flatfielded, extracted)
|
Cross Dispersed, High-resolution |
| Filter |
source |
mag. |
itime(sec) x coadd x frames |
slit (") |
seeing (") |
λ + order |
measured SNR/pix |
Mag. for SNR=100 in 1hr |
| NIRSPEC-3 |
HD 1561 |
J=6.33 |
6 x 5 x 2 |
0.432 x 12 |
˜0.5 |
1.29μm m=59 |
110 |
J=10.9 |
| NIRSPEC-5 |
HD 1561 |
H=6.38 |
6 x 5 x 1 |
0.432 x 12 |
˜0.5 |
1.56μm m=49 |
90 |
H=11.3 |
| NIRSPEC-7 |
HR 3067 |
K=4.66 |
4 x 1 x 8 |
0.576 x 12 |
˜0.5 |
2.23μm m=34 |
150 |
K=10.6 |
| KL |
HR 1552 |
L=3.8 |
1.2 x 5 x 4 |
0.432 x 24 |
˜0.4 |
3.235μm m=23 |
100 |
L=9.2 |
|
|
|
|
|
|
3.757μm m=20 |
150 |
L=10.1 |
| M-wide |
HR 1412 |
M=2.8 |
1.0 x 30 x 8 |
0.432 x 24 |
˜0.4 |
4.615μm m=16 |
400 |
M=8.7 |
Notes
- Values are based on observations of a point source subject to slit losses
- Magnitude equivalent to reach SNR=100 in 1 hour assumes noise is
dominated by source or sky background
The following relation can be used to estimate the SNR/pixel values in other observing cases from raw frames:
Sgt S = source count rate (ADU/s)
SNR = ______________________ where B = rms in background (ADU); implicit time dependence
______________________ D = dark current (0.7 e-/s/pix)
/ g = gain (5.7 e-/ADU for SPEC)
/ Sgt + Bg + Dt + r^2 t = integration time (itime x coadds)
\/ r = read noise ( 2 x (23 e-)^2 = 1058 e- for nod pair)