A.2 Throughputs and Signal-to-Noise Ratio Data
A.2.1 Sensitivity Units and Conversions
This appendix contains plots of throughputs for each WFC3 filter. Section 9.3 explains how to use these throughputs to calculate expected count rates from your source.
The first figure for each filter gives the integrated system throughput based on on-orbit observations of spectrophotometric standards. This is the combination of the efficiencies of the detector and of the optical elements in the light path. The throughput is defined as the number of detected counts/second/cm2 of telescope area relative to the incident flux in photons/cm2/s. For both the UVIS and IR channels, "counts" is the number of electrons detected. In both channels the detected counts obey Poisson statistics, except that at short wavelengths in the UVIS channel, a single incoming photon has a finite chance of producing multiple electrons in the CCD. Section 5.4.2 describes this phenomenon, which was measured to have a much smaller effect in the UVIS detectors compared to theoretical predictions. The signal-to-noise plots in this appendix have been corrected to remove multiple electrons generated by UV photons, using a correction that is intermediate between the theoretical and measured UVIS "quantum yields." The throughput includes all obscuration effects in the optical train (e.g., due to the HST secondary).
All wavelength measurements for the UVIS and IR channel filters were done in a gaseous medium: air for UVIS measurements and helium for IR measurements. The results have been converted to vacuum wavelengths using the indices of refraction of the gaseous media. The UVIS laboratory measurements were done at a temperature of 20°C, whereas the filters are operated on orbit at 0°C; this may lead to wavelength shifts which are expected to be small. The IR laboratory measurements were done at a temperature of –30°C, whereas the filters are operated on orbit at –35°C; this may lead to wavelength shifts which are expected to be very small.
Note that the tables in the stsynphot
package and the WFC3 Exposure Time Calculator all assume vacuum wavelengths for both the UVIS and IR filter transmission data.
Because we have applied a correction to the throughputs for quantum yield in order to derive appropriate counting statistics for the source, the sensitivity calculations shown here are conservative in background- or read-noise-dominated regimes; the additional signal electrons from the enhanced UV quantum yield will increase the detection of faint sources in the 200–300 nm range somewhat vs. these sample calculations.
To recalculate the throughputs with the most recent detector QE tables in stsynphot
, you can create total-system-throughput tables (instrument plus OTA) using the stsynphot
band
function, which takes any valid obsmode
as input and produces a table with two columns of data called "wavelength" and "throughput" as its output.
For example, to evaluate the UVIS1 throughput for the F475W filter in an infinite aperture at the time of WFC3's installation, you would use the following commands:
import stsynphot as stsyn bp = stsyn.band('wfc3,uvis1,f475w')
Whereas to evaluate the UVIS1 F475W throughput on MJD 58000 for a 10-pixel radius aperture, you would use the following commands:
import stsynphot as stsyn bp = stsyn.band('wfc3,uvis1,f475w,mjd#58000,aper#0.40')
A Jupyter Notebook is provided to calculate filter throughputs and inverse sensitivities for the WFC3 UVIS and IR detectors.
A.2.2 Signal-to-Noise Ratio
For each imaging mode, plots are provided to estimate the signal-to-noise ratio (S/N) for a representative source. The first figure shows S/N for point sources. The second figure shows S/N for uniform extended sources of area 1 arcsec2.
The different line styles in the S/N figures delineate regions where different sources of noise dominate. If the total noise from backgrounds (read noise, sky, thermal, dark) is larger than the noise from the source, the observation is considered to be background-dominated, and the line style reflects which background source is largest. Note that for the WFC3 detectors, the dark current can never be the largest source of noise when a source is background-dominated, because the read noise is always larger than the dark count noise when exposures are 1000 s or less. The point- and extended-source S/N figures assume average sky levels. These plots also indicate where an observation will saturate the full well of the detector.
For point sources, an aperture size of 5 × 5 pixels has been used for the UVIS channel, while an aperture size of 3 × 3 pixels has been used for the IR channel. For extended sources, a 1 arcsec2 aperture was used. The read noise has been computed assuming a number of readouts NREAD
= integer (t/1000 s), where t is the exposure time, with a minimum NREAD
=2.
In situations requiring more detailed calculations (non-stellar spectra, extended sources, other sky background levels, unknown target V magnitude, etc.), the WFC3 Exposure Time Calculator should be used.
Follow these steps to use the signal-to-noise plots:
Determine the AB magnitude of your source at the wavelength of interest. There are several ways to do this.
- Examine Tables A.1, A.2, or A.3 and find ABν for the desired spectral type and filter. Sum the V magnitude of the target and ABν derived from the table.
- Alternatively, compute ABMAG (= V+ABν) from the source flux, using the relation.ABMAG=-2.5\log f_v - 48.60~~, or
ABMAG=-2.5\log f_{\lambda} - 5 \log\lambda - 2.406~~. - Find the appropriate plot for the filter in question, and locate V+ABν on the horizontal axis. Then read off the signal-to-noise ratio for the desired exposure time, or vice-versa.
Note that the plots show the S/N as a function of source magnitude for exposure times as short as 0.1 s, although the minimum exposure time for the UVIS channel is actually 0.5 s.
Table A.1: Color corrections ABν to go from Johnson V magnitude to AB magnitude for WFC3 as a function of stellar effective temperature.
Teff | ||||||||
Mode | 2500K | 5000K | 7500K | 10000K | 15000K | 20000K | 30000K | 50000K |
UVIS/F200LP | –2.22 | 0.45 | 0.48 | 0.40 | 0.08 | –0.12 | –0.40 | –0.57 |
UVIS/F218W | 7.21 | 7.82 | 2.95 | 1.51 | 0.09 | –0.53 | –1.22 | –1.55 |
UVIS/F225W | 6.07 | 7.22 | 2.84 | 1.51 | 0.12 | –0.49 | –1.15 | –1.46 |
UVIS/F275W | 7.30 | 5.30 | 2.27 | 1.35 | 0.10 | –0.42 | –0.96 | –1.24 |
UVIS/F280N | 3.29 | 4.49 | 2.50 | 1.44 | 0.13 | –0.40 | –0.90 | –1.17 |
UVIS/F300X | 5.96 | 4.05 | 1.98 | 1.26 | 0.10 | –0.39 | –0.91 | –1.19 |
UVIS/F336W | 4.98 | 2.71 | 1.31 | 1.00 | 0.10 | –0.26 | –0.64 | –0.86 |
UVIS/F343N | 4.74 | 2.62 | 1.24 | 0.97 | 0.11 | –0.24 | –0.60 | –0.82 |
UVIS/F350LP | –2.64 | 0.07 | 0.18 | 0.18 | 0.09 | 0.04 | –0.02 | –0.07 |
UVIS/F373N | 7.03 | 2.53 | 1.10 | 0.94 | 0.21 | –0.09 | –0.43 | –0.65 |
UVIS/F390M | 4.25 | 2.08 | 0.67 | 0.25 | –0.20 | –0.33 | –0.48 | –0.60 |
UVIS/F390W | 3.80 | 1.63 | 0.59 | 0.26 | –0.14 | –0.29 | –0.47 | –0.60 |
UVIS/F395N | 3.91 | 1.92 | 0.67 | 0.15 | –0.27 | –0.37 | –0.49 | –0.58 |
UVIS/F410M | 2.96 | 1.16 | 0.29 | –0.10 | –0.32 | –0.39 | –0.46 | –0.52 |
UVIS/F438W | 2.28 | 0.86 | 0.18 | –0.12 | –0.28 | –0.33 | –0.39 | –0.43 |
UVIS/F467M | 1.74 | 0.34 | 0.02 | –0.15 | –0.22 | –0.24 | –0.26 | –0.27 |
UVIS/F469N | 1.64 | 0.33 | 0.03 | –0.14 | –0.21 | –0.24 | –0.26 | –0.26 |
UVIS/F475W | 1.23 | 0.44 | 0.09 | –0.07 | –0.17 | –0.20 | –0.24 | –0.26 |
UVIS/F475X | 0.61 | 0.35 | 0.12 | –0.01 | –0.12 | –0.15 | –0.19 | –0.23 |
UVIS/F487N | 1.47 | 0.29 | 0.20 | 0.28 | 0.06 | –0.02 | –0.11 | –0.17 |
UVIS/F502N | 2.32 | 0.32 | 0.02 | –0.07 | –0.11 | –0.12 | –0.14 | –0.15 |
UVIS/FQ508N | 1.07 | 0.32 | 0.01 | –0.06 | –0.08 | –0.10 | –0.11 | –0.12 |
UVIS/F547M | 0.08 | 0.03 | 0.02 | 0.01 | 0.01 | 0.01 | 0.01 | 0.02 |
UVIS/F555W | 0.15 | 0.09 | 0.03 | –0.01 | –0.03 | –0.04 | –0.05 | –0.06 |
UVIS/F600LP | –3.71 | –0.42 | 0.09 | 0.34 | 0.47 | 0.52 | 0.57 | 0.60 |
UVIS/F606W | –0.83 | –0.11 | 0.04 | 0.10 | 0.12 | 0.12 | 0.13 | 0.13 |
UVIS/F621M | –1.23 | –0.26 | 0.03 | 0.16 | 0.22 | 0.25 | 0.27 | 0.28 |
UVIS/F625W | –1.17 | –0.25 | 0.04 | 0.16 | 0.22 | 0.24 | 0.26 | 0.27 |
UVIS/F631N | –0.33 | –0.28 | 0.03 | 0.17 | 0.24 | 0.27 | 0.30 | 0.31 |
UVIS/F645N | –2.20 | –0.29 | 0.04 | 0.20 | 0.28 | 0.31 | 0.35 | 0.35 |
UVIS/F656N | –1.99 | –0.26 | 0.36 | 0.63 | 0.56 | 0.54 | 0.52 | 0.45 |
UVIS/F657N | –2.31 | –0.31 | 0.14 | 0.37 | 0.39 | 0.41 | 0.42 | 0.41 |
UVIS/F658N | –2.04 | –0.31 | 0.18 | 0.42 | 0.42 | 0.43 | 0.44 | 0.41 |
UVIS/F665N | –1.30 | –0.35 | 0.06 | 0.26 | 0.34 | 0.38 | 0.42 | 0.42 |
UVIS/F673N | –0.69 | –0.37 | 0.04 | 0.24 | 0.35 | 0.39 | 0.44 | 0.45 |
UVIS/F680N | –1.61 | –0.38 | 0.05 | 0.26 | 0.38 | 0.42 | 0.47 | 0.48 |
UVIS/F689M | –1.69 | –0.37 | 0.06 | 0.28 | 0.39 | 0.43 | 0.47 | 0.48 |
UVIS/F763M | –3.09 | –0.45 | 0.09 | 0.37 | 0.53 | 0.59 | 0.65 | 0.69 |
UVIS/F775W | –3.60 | –0.45 | 0.09 | 0.38 | 0.54 | 0.59 | 0.65 | 0.70 |
UVIS/F814W | –4.14 | –0.48 | 0.12 | 0.43 | 0.60 | 0.67 | 0.74 | 0.79 |
UVIS/F845M | –4.56 | –0.51 | 0.16 | 0.51 | 0.70 | 0.77 | 0.84 | 0.91 |
UVIS/F850LP | –5.03 | –0.56 | 0.21 | 0.56 | 0.79 | 0.89 | 0.98 | 1.06 |
UVIS/F953N | –5.52 | –0.59 | 0.27 | 0.68 | 0.91 | 1.00 | 1.10 | 1.16 |
UVIS/FQ232N | 2.15 | 4.54 | 2.68 | 1.53 | 0.20 | –0.43 | –1.12 | –1.46 |
UVIS/FQ243N | 2.84 | 5.10 | 2.76 | 1.52 | 0.18 | –0.44 | –1.11 | –1.40 |
UVIS/FQ378N | 4.90 | 2.32 | 0.86 | 0.61 | 0.01 | –0.20 | –0.44 | –0.62 |
UVIS/FQ387N | 6.34 | 2.42 | 0.61 | 0.25 | –0.21 | –0.34 | –0.49 | –0.61 |
UVIS/FQ422M | 5.05 | 1.17 | 0.18 | –0.22 | –0.36 | –0.41 | –0.46 | –0.48 |
UVIS/FQ436N | 2.64 | 0.84 | 0.23 | 0.08 | –0.16 | –0.24 | –0.31 | –0.39 |
UVIS/FQ437N | 2.59 | 0.83 | 0.18 | 0.00 | –0.21 | –0.28 | –0.34 | –0.40 |
UVIS/FQ492N | 0.91 | 0.27 | 0.04 | –0.02 | –0.10 | –0.13 | –0.16 | –0.17 |
UVIS/FQ575N | –0.58 | –0.18 | 0.01 | 0.07 | 0.10 | 0.11 | 0.13 | 0.13 |
UVIS/FQ619N | 0.72 | –0.25 | 0.03 | 0.15 | 0.22 | 0.24 | 0.27 | 0.27 |
UVIS/FQ634N | –0.96 | –0.28 | 0.03 | 0.18 | 0.26 | 0.29 | 0.32 | 0.32 |
UVIS/FQ672N | –0.77 | –0.35 | 0.04 | 0.23 | 0.34 | 0.38 | 0.42 | 0.44 |
UVIS/FQ674N | –0.39 | –0.37 | 0.04 | 0.24 | 0.35 | 0.39 | 0.43 | 0.44 |
UVIS/FQ727N | –2.81 | –0.41 | 0.07 | 0.32 | 0.46 | 0.52 | 0.57 | 0.60 |
UVIS/FQ750N | –3.06 | –0.44 | 0.08 | 0.36 | 0.51 | 0.57 | 0.63 | 0.66 |
UVIS/FQ889N | –4.98 | –0.55 | 0.20 | 0.57 | 0.78 | 0.86 | 0.95 | 1.01 |
UVIS/FQ906N | –5.15 | –0.56 | 0.21 | 0.57 | 0.79 | 0.88 | 0.98 | 1.05 |
UVIS/FQ924N | –4.89 | –0.57 | 0.26 | 0.66 | 0.87 | 0.95 | 1.04 | 1.10 |
UVIS/FQ937N | –5.19 | –0.58 | 0.19 | 0.48 | 0.77 | 0.89 | 1.01 | 1.11 |
IR/F098M | –5.40 | –0.60 | 0.25 | 0.60 | 0.88 | 1.00 | 1.12 | 1.21 |
IR/F105W | –5.68 | –0.62 | 0.31 | 0.69 | 0.98 | 1.11 | 1.24 | 1.34 |
IR/F110W | –5.77 | –0.64 | 0.39 | 0.80 | 1.12 | 1.25 | 1.39 | 1.49 |
IR/F125W | –5.91 | –0.67 | 0.48 | 0.94 | 1.28 | 1.43 | 1.58 | 1.69 |
IR/F126N | –5.99 | –0.67 | 0.49 | 0.96 | 1.31 | 1.46 | 1.61 | 1.72 |
IR/F127M | –6.04 | –0.67 | 0.52 | 1.01 | 1.35 | 1.49 | 1.65 | 1.75 |
IR/F128N | –6.08 | –0.67 | 0.59 | 1.11 | 1.41 | 1.55 | 1.69 | 1.78 |
IR/F130N | –6.13 | –0.68 | 0.53 | 1.02 | 1.37 | 1.52 | 1.68 | 1.79 |
IR/F132N | –6.04 | –0.67 | 0.54 | 1.03 | 1.39 | 1.55 | 1.71 | 1.82 |
IR/F139M | –5.64 | –0.69 | 0.60 | 1.11 | 1.49 | 1.64 | 1.81 | 1.92 |
IR/F140W | –5.89 | –0.69 | 0.61 | 1.12 | 1.49 | 1.64 | 1.80 | 1.92 |
IR/F153M | –6.03 | –0.71 | 0.73 | 1.29 | 1.69 | 1.85 | 2.02 | 2.14 |
IR/F160W | –6.05 | –0.70 | 0.74 | 1.30 | 1.69 | 1.85 | 2.02 | 2.15 |
IR/F164N | –6.39 | –0.70 | 0.84 | 1.42 | 1.82 | 1.99 | 2.16 | 2.28 |
IR/F167N | –6.32 | –0.69 | 0.84 | 1.41 | 1.83 | 2.00 | 2.18 | 2.31 |
Table A.2: Color corrections ABν to go from Johnson V magnitude to AB magnitude for WFC3 as a function of age in an instantaneous burst population.
Age | |||||
Mode | 10 Gyr | 1 Gyr | 100 Myr | 10 Myr | 1 Myr |
UVIS/F200LP | 0.38 | 0.48 | 0.29 | 0.02 | –0.48 |
UVIS/F218W | 6.11 | 3.89 | 1.06 | 0.15 | –1.22 |
UVIS/F225W | 5.83 | 3.76 | 1.03 | 0.16 | –1.15 |
UVIS/F275W | 4.75 | 3.14 | 0.93 | 0.19 | –0.97 |
UVIS/F280N | 4.32 | 3.03 | 0.89 | 0.21 | –0.92 |
UVIS/F300X | 3.95 | 2.80 | 0.89 | 0.20 | –0.94 |
UVIS/F336W | 2.69 | 1.98 | 0.77 | 0.27 | –0.67 |
UVIS/F343N | 2.55 | 1.89 | 0.76 | 0.28 | –0.63 |
UVIS/F350LP | –0.09 | 0.04 | 0.06 | –0.06 | –0.04 |
UVIS/F373N | 2.28 | 1.57 | 0.66 | 0.34 | –0.49 |
UVIS/F390M | 2.03 | 1.12 | 0.22 | 0.14 | –0.50 |
UVIS/F390W | 1.63 | 1.00 | 0.27 | 0.15 | –0.50 |
UVIS/F395N | 1.88 | 1.03 | 0.14 | 0.11 | –0.49 |
UVIS/F410M | 1.23 | 0.64 | 0.02 | 0.02 | –0.47 |
UVIS/F438W | 0.90 | 0.48 | 0.01 | 0.02 | –0.39 |
UVIS/F467M | 0.44 | 0.22 | –0.03 | –0.01 | –0.26 |
UVIS/F469N | 0.46 | 0.23 | –0.02 | –0.01 | –0.25 |
UVIS/F475W | 0.48 | 0.27 | 0.02 | 0.04 | –0.23 |
UVIS/F475X | 0.38 | 0.24 | 0.03 | 0.03 | –0.20 |
UVIS/F487N | 0.36 | 0.27 | 0.12 | 0.10 | –0.14 |
UVIS/F502N | 0.33 | 0.17 | 0.02 | 0.08 | –0.12 |
UVIS/F547M | 0.04 | 0.03 | 0.03 | 0.03 | 0.02 |
UVIS/F555W | 0.11 | 0.07 | 0.02 | 0.01 | –0.05 |
UVIS/F600LP | –0.72 | –0.38 | –0.04 | –0.27 | 0.54 |
UVIS/F606W | –0.17 | –0.08 | 0.01 | –0.04 | 0.13 |
UVIS/F621M | –0.33 | –0.18 | 0.00 | –0.10 | 0.26 |
UVIS/F625W | –0.33 | –0.18 | –0.00 | –0.10 | 0.26 |
UVIS/F631N | –0.34 | –0.19 | 0.00 | –0.10 | 0.29 |
UVIS/F645N | –0.43 | –0.23 | –0.02 | –0.15 | 0.33 |
UVIS/F656N | –0.45 | –0.18 | 0.06 | –0.16 | 0.37 |
UVIS/F657N | –0.47 | –0.22 | 0.00 | –0.18 | 0.37 |
UVIS/F658N | –0.47 | –0.22 | 0.00 | –0.18 | 0.37 |
UVIS/F665N | –0.48 | –0.26 | –0.03 | –0.18 | 0.39 |
UVIS/F673N | –0.49 | –0.28 | –0.02 | –0.15 | 0.42 |
UVIS/F680N | –0.54 | –0.30 | –0.02 | –0.17 | 0.45 |
UVIS/F689M | –0.53 | –0.29 | –0.02 | –0.18 | 0.45 |
UVIS/F763M | –0.77 | –0.40 | –0.05 | –0.32 | 0.64 |
UVIS/F775W | –0.78 | –0.41 | –0.05 | –0.31 | 0.64 |
UVIS/F814W | –0.89 | –0.47 | –0.07 | –0.36 | 0.71 |
UVIS/F845M | –1.00 | –0.53 | –0.09 | –0.41 | 0.82 |
UVIS/F850LP | –1.18 | –0.65 | –0.13 | –0.47 | 0.96 |
UVIS/F953N | –1.27 | –0.71 | –0.12 | –0.50 | 1.06 |
UVIS/FQ232N | 4.48 | 3.43 | 1.03 | 0.17 | –1.14 |
UVIS/FQ243N | 4.88 | 3.62 | 0.98 | 0.14 | –1.10 |
UVIS/FQ378N | 2.24 | 1.37 | 0.42 | 0.22 | –0.51 |
UVIS/FQ387N | 2.27 | 1.16 | 0.23 | 0.14 | –0.51 |
UVIS/FQ422M | 1.16 | 0.55 | –0.03 | 0.01 | –0.44 |
UVIS/FQ436N | 0.86 | 0.49 | 0.04 | 0.05 | –0.36 |
UVIS/FQ437N | 0.86 | 0.46 | 0.00 | 0.03 | –0.37 |
UVIS/FQ492N | 0.31 | 0.17 | 0.01 | 0.05 | –0.15 |
UVIS/FQ508N | 0.31 | 0.17 | 0.04 | 0.12 | –0.09 |
UVIS/FQ575N | –0.18 | –0.08 | 0.00 | –0.06 | 0.12 |
UVIS/FQ619N | –0.28 | –0.16 | 0.02 | –0.06 | 0.26 |
UVIS/FQ634N | –0.37 | –0.21 | –0.01 | –0.12 | 0.30 |
UVIS/FQ672N | –0.47 | –0.27 | –0.02 | –0.16 | 0.40 |
UVIS/FQ674N | –0.48 | –0.27 | –0.02 | –0.16 | 0.41 |
UVIS/FQ727N | –0.65 | –0.34 | –0.01 | –0.26 | 0.56 |
UVIS/FQ750N | –0.81 | –0.43 | –0.07 | –0.33 | 0.61 |
UVIS/FQ889N | –1.12 | –0.61 | –0.14 | –0.46 | 0.91 |
UVIS/FQ906N | –1.22 | –0.68 | –0.15 | –0.49 | 0.94 |
UVIS/FQ924N | –1.21 | –0.65 | –0.12 | –0.48 | 1.00 |
UVIS/FQ937N | –1.16 | –0.65 | –0.11 | –0.47 | 1.00 |
IR/F098M | –1.35 | –0.74 | –0.15 | –0.51 | 1.10 |
IR/F105W | –1.39 | –0.74 | –0.14 | –0.54 | 1.22 |
IR/F110W | –1.38 | –0.70 | –0.11 | –0.57 | 1.36 |
IR/F125W | –1.39 | –0.67 | –0.08 | –0.60 | 1.57 |
IR/F126N | –1.37 | –0.64 | –0.07 | –0.62 | 1.60 |
IR/F127M | –1.38 | –0.64 | –0.07 | –0.62 | 1.62 |
IR/F128N | –1.39 | –0.64 | –0.07 | –0.63 | 1.64 |
IR/F130N | –1.40 | –0.65 | –0.07 | –0.63 | 1.66 |
IR/F132N | –1.40 | –0.64 | –0.07 | –0.62 | 1.69 |
IR/F139M | –1.37 | –0.62 | –0.05 | –0.60 | 1.78 |
IR/F140W | –1.41 | –0.65 | –0.06 | –0.64 | 1.77 |
IR/F153M | –1.49 | –0.69 | –0.07 | –0.70 | 1.98 |
IR/F160W | –1.49 | –0.68 | –0.07 | –0.70 | 1.97 |
IR/F164N | –1.59 | –0.75 | –0.11 | –0.79 | 2.10 |
IR/F167N | –1.58 | –0.74 | –0.10 | –0.78 | 2.13 |
Table A.3: Color corrections ABν to go from Johnson V magnitude to AB magnitude for WFC3 as a function of age in a population with constant star formation.
Age | |||||
Mode | 10 Gyr | 1 Gyr | 100 Myr | 10 Myr | 1 Myr |
UVIS/F200LP | 0.31 | 0.24 | 0.03 | –0.15 | –0.48 |
UVIS/F218W | 1.39 | 0.79 | 0.08 | –0.48 | –1.22 |
UVIS/F225W | 1.39 | 0.79 | 0.09 | –0.44 | –1.15 |
UVIS/F275W | 1.35 | 0.78 | 0.12 | –0.36 | –0.97 |
UVIS/F280N | 1.34 | 0.77 | 0.14 | –0.33 | –0.92 |
UVIS/F300X | 1.31 | 0.76 | 0.13 | –0.34 | –0.93 |
UVIS/F336W | 1.15 | 0.71 | 0.19 | –0.21 | –0.66 |
UVIS/F343N | 1.13 | 0.71 | 0.20 | –0.18 | –0.62 |
UVIS/F350LP | 0.00 | 0.03 | –0.01 | –0.01 | –0.04 |
UVIS/F373N | 1.04 | 0.66 | 0.24 | –0.11 | –0.49 |
UVIS/F390M | 0.67 | 0.28 | –0.00 | –0.25 | –0.50 |
UVIS/F390W | 0.64 | 0.30 | 0.03 | –0.23 | –0.49 |
UVIS/F395N | 0.60 | 0.21 | –0.04 | –0.27 | –0.49 |
UVIS/F410M | 0.37 | 0.07 | –0.11 | –0.30 | –0.47 |
UVIS/F438W | 0.29 | 0.05 | –0.09 | –0.25 | –0.39 |
UVIS/F467M | 0.14 | –0.00 | –0.08 | –0.18 | –0.26 |
UVIS/F469N | 0.15 | 0.00 | –0.07 | –0.17 | –0.25 |
UVIS/F475W | 0.18 | 0.04 | –0.03 | –0.14 | –0.23 |
UVIS/F475X | 0.16 | 0.05 | –0.02 | –0.11 | –0.20 |
UVIS/F487N | 0.21 | 0.14 | 0.05 | –0.05 | –0.14 |
UVIS/F502N | 0.13 | 0.04 | 0.01 | –0.06 | –0.13 |
UVIS/F547M | 0.03 | 0.03 | 0.03 | 0.03 | 0.02 |
UVIS/F555W | 0.05 | 0.02 | –0.00 | –0.03 | –0.05 |
UVIS/F600LP | –0.36 | –0.13 | –0.05 | 0.22 | 0.54 |
UVIS/F606W | –0.06 | –0.00 | 0.01 | 0.07 | 0.13 |
UVIS/F621M | –0.14 | –0.03 | 0.01 | 0.13 | 0.26 |
UVIS/F625W | –0.14 | –0.03 | 0.01 | 0.12 | 0.26 |
UVIS/F631N | –0.15 | –0.03 | 0.02 | 0.14 | 0.29 |
UVIS/F645N | –0.19 | –0.05 | –0.01 | 0.15 | 0.33 |
UVIS/F656N | –0.16 | 0.01 | 0.02 | 0.19 | 0.37 |
UVIS/F657N | –0.20 | –0.04 | –0.01 | 0.16 | 0.37 |
UVIS/F658N | –0.20 | –0.04 | –0.02 | 0.16 | 0.37 |
UVIS/F665N | –0.23 | –0.07 | –0.02 | 0.16 | 0.39 |
UVIS/F673N | –0.23 | –0.06 | 0.01 | 0.19 | 0.42 |
UVIS/F680N | –0.26 | –0.07 | 0.00 | 0.20 | 0.45 |
UVIS/F689M | –0.25 | –0.07 | –0.01 | 0.20 | 0.45 |
UVIS/F763M | –0.39 | –0.13 | –0.06 | 0.25 | 0.64 |
UVIS/F775W | –0.39 | –0.14 | –0.06 | 0.25 | 0.64 |
UVIS/F814W | –0.46 | –0.18 | –0.08 | 0.26 | 0.71 |
UVIS/F845M | –0.53 | –0.22 | –0.12 | 0.28 | 0.82 |
UVIS/F850LP | –0.66 | –0.31 | –0.14 | 0.30 | 0.96 |
UVIS/F953N | –0.72 | –0.34 | –0.15 | 0.32 | 1.06 |
UVIS/FQ232N | 1.37 | 0.79 | 0.10 | –0.43 | –1.14 |
UVIS/FQ243N | 1.37 | 0.78 | 0.08 | –0.43 | –1.10 |
UVIS/FQ378N | 0.85 | 0.46 | 0.10 | –0.20 | –0.50 |
UVIS/FQ387N | 0.70 | 0.29 | 0.01 | –0.25 | –0.51 |
UVIS/FQ422M | 0.32 | 0.02 | –0.12 | –0.30 | –0.44 |
UVIS/FQ436N | 0.31 | 0.08 | –0.06 | –0.22 | –0.37 |
UVIS/FQ437N | 0.28 | 0.05 | –0.09 | –0.24 | –0.38 |
UVIS/FQ492N | 0.12 | 0.03 | –0.01 | –0.09 | –0.15 |
UVIS/FQ508N | 0.14 | 0.06 | 0.04 | –0.03 | –0.09 |
UVIS/FQ575N | –0.07 | –0.01 | –0.00 | 0.06 | 0.13 |
UVIS/FQ619N | –0.12 | –0.01 | 0.03 | 0.14 | 0.26 |
UVIS/FQ634N | –0.17 | –0.04 | 0.00 | 0.14 | 0.30 |
UVIS/FQ672N | –0.22 | –0.06 | –0.00 | 0.18 | 0.40 |
UVIS/FQ674N | –0.22 | –0.06 | 0.00 | 0.19 | 0.41 |
UVIS/FQ727N | –0.31 | –0.09 | –0.03 | 0.23 | 0.56 |
UVIS/FQ750N | –0.42 | –0.16 | –0.08 | 0.23 | 0.61 |
UVIS/FQ889N | –0.62 | –0.28 | –0.15 | 0.28 | 0.91 |
UVIS/FQ906N | –0.69 | –0.34 | –0.17 | 0.27 | 0.94 |
UVIS/FQ924N | –0.67 | –0.30 | –0.14 | 0.31 | 1.00 |
UVIS/FQ937N | –0.65 | –0.30 | –0.14 | 0.31 | 0.99 |
IR/F098M | –0.76 | –0.37 | –0.16 | 0.33 | 1.10 |
IR/F105W | –0.78 | –0.37 | –0.17 | 0.36 | 1.22 |
IR/F110W | –0.76 | –0.33 | –0.17 | 0.39 | 1.36 |
IR/F125W | –0.74 | –0.30 | –0.17 | 0.44 | 1.57 |
IR/F126N | –0.73 | –0.29 | –0.18 | 0.45 | 1.60 |
IR/F127M | –0.73 | –0.29 | –0.18 | 0.45 | 1.62 |
IR/F128N | –0.74 | –0.29 | –0.18 | 0.45 | 1.64 |
IR/F130N | –0.74 | –0.29 | –0.18 | 0.46 | 1.66 |
IR/F132N | –0.74 | –0.28 | –0.17 | 0.47 | 1.69 |
IR/F139M | –0.71 | –0.25 | –0.14 | 0.49 | 1.78 |
IR/F140W | –0.75 | –0.28 | –0.17 | 0.47 | 1.77 |
IR/F153M | –0.81 | –0.32 | –0.20 | 0.47 | 1.97 |
IR/F160W | –0.80 | –0.32 | –0.21 | 0.46 | 1.97 |
IR/F164N | –0.88 | –0.39 | –0.27 | 0.43 | 2.10 |
IR/F167N | –0.88 | –0.38 | –0.26 | 0.44 | 2.13 |
-
WFC3 Instrument Handbook
- • Acknowledgments
- Chapter 1: Introduction to WFC3
- Chapter 2: WFC3 Instrument Description
- Chapter 3: Choosing the Optimum HST Instrument
- Chapter 4: Designing a Phase I WFC3 Proposal
- Chapter 5: WFC3 Detector Characteristics and Performance
-
Chapter 6: UVIS Imaging with WFC3
- • 6.1 WFC3 UVIS Imaging
- • 6.2 Specifying a UVIS Observation
- • 6.3 UVIS Channel Characteristics
- • 6.4 UVIS Field Geometry
- • 6.5 UVIS Spectral Elements
- • 6.6 UVIS Optical Performance
- • 6.7 UVIS Exposure and Readout
- • 6.8 UVIS Sensitivity
- • 6.9 Charge Transfer Efficiency
- • 6.10 Other Considerations for UVIS Imaging
- • 6.11 UVIS Observing Strategies
- Chapter 7: IR Imaging with WFC3
- Chapter 8: Slitless Spectroscopy with WFC3
-
Chapter 9: WFC3 Exposure-Time Calculation
- • 9.1 Overview
- • 9.2 The WFC3 Exposure Time Calculator - ETC
- • 9.3 Calculating Sensitivities from Tabulated Data
- • 9.4 Count Rates: Imaging
- • 9.5 Count Rates: Slitless Spectroscopy
- • 9.6 Estimating Exposure Times
- • 9.7 Sky Background
- • 9.8 Interstellar Extinction
- • 9.9 Exposure-Time Calculation Examples
- Chapter 10: Overheads and Orbit Time Determinations
-
Appendix A: WFC3 Filter Throughputs
- • A.1 Introduction
-
A.2 Throughputs and Signal-to-Noise Ratio Data
- • UVIS F200LP
- • UVIS F218W
- • UVIS F225W
- • UVIS F275W
- • UVIS F280N
- • UVIS F300X
- • UVIS F336W
- • UVIS F343N
- • UVIS F350LP
- • UVIS F373N
- • UVIS F390M
- • UVIS F390W
- • UVIS F395N
- • UVIS F410M
- • UVIS F438W
- • UVIS F467M
- • UVIS F469N
- • UVIS F475W
- • UVIS F475X
- • UVIS F487N
- • UVIS F502N
- • UVIS F547M
- • UVIS F555W
- • UVIS F600LP
- • UVIS F606W
- • UVIS F621M
- • UVIS F625W
- • UVIS F631N
- • UVIS F645N
- • UVIS F656N
- • UVIS F657N
- • UVIS F658N
- • UVIS F665N
- • UVIS F673N
- • UVIS F680N
- • UVIS F689M
- • UVIS F763M
- • UVIS F775W
- • UVIS F814W
- • UVIS F845M
- • UVIS F850LP
- • UVIS F953N
- • UVIS FQ232N
- • UVIS FQ243N
- • UVIS FQ378N
- • UVIS FQ387N
- • UVIS FQ422M
- • UVIS FQ436N
- • UVIS FQ437N
- • UVIS FQ492N
- • UVIS FQ508N
- • UVIS FQ575N
- • UVIS FQ619N
- • UVIS FQ634N
- • UVIS FQ672N
- • UVIS FQ674N
- • UVIS FQ727N
- • UVIS FQ750N
- • UVIS FQ889N
- • UVIS FQ906N
- • UVIS FQ924N
- • UVIS FQ937N
- • IR F098M
- • IR F105W
- • IR F110W
- • IR F125W
- • IR F126N
- • IR F127M
- • IR F128N
- • IR F130N
- • IR F132N
- • IR F139M
- • IR F140W
- • IR F153M
- • IR F160W
- • IR F164N
- • IR F167N
- Appendix B: Geometric Distortion
- Appendix C: Dithering and Mosaicking
- Appendix D: Bright-Object Constraints and Image Persistence
-
Appendix E: Reduction and Calibration of WFC3 Data
- • E.1 Overview
- • E.2 The STScI Reduction and Calibration Pipeline
- • E.3 The SMOV Calibration Plan
- • E.4 The Cycle 17 Calibration Plan
- • E.5 The Cycle 18 Calibration Plan
- • E.6 The Cycle 19 Calibration Plan
- • E.7 The Cycle 20 Calibration Plan
- • E.8 The Cycle 21 Calibration Plan
- • E.9 The Cycle 22 Calibration Plan
- • E.10 The Cycle 23 Calibration Plan
- • E.11 The Cycle 24 Calibration Plan
- • E.12 The Cycle 25 Calibration Plan
- • E.13 The Cycle 26 Calibration Plan
- • E.14 The Cycle 27 Calibration Plan
- • E.15 The Cycle 28 Calibration Plan
- • E.16 The Cycle 29 Calibration Plan
- • E.17 The Cycle 30 Calibration Plan
- • E.18 The Cycle 31 Calibration Plan
- • Glossary