"""Detector geometry for the WCC focal plane (array dims live here, not in wcc_etc)."""
from dataclasses import dataclass
from astropy import units as u
from wcc_etc import Simulation
from wcc_etc.io import KIND_NAMES, SENSORFILTER_FOCUS
from wcc_etc.scene import get_scene
# Full-frame pixel counts (manufacturer values; wcc_etc Sensor only stores area).
ARRAY_DIMS = {
"zwo": (9568, 6380), # Sony IMX455 / ZWO ASI6200MM
"qcmos": (4096, 2304), # Hamamatsu HWK4123
}
FOCUS_WAVES = {"0wave": 0, "1wave": 1, "2wave": 2}
def _validate_sensorfilter(sensorfilter):
"""Validate that sensorfilter is known. Raises ValueError with valid keys."""
if sensorfilter not in SENSORFILTER_FOCUS:
raise ValueError(
f"Unknown sensorfilter {sensorfilter!r}. "
f"Valid keys: {sorted(SENSORFILTER_FOCUS)}"
)
[docs]
@dataclass(frozen=True)
class DetectorGeometry:
nx: int
ny: int
pixel_size_um: float
plate_scale_mas: float
default_focus: int
[docs]
def make_base_simulation(sensorfilter, gain_mode=None):
"""A wcc_etc Simulation for this sensorfilter (G2V mag-15 source, zodi bg).
Used for geometry, PSF context parameters, and sky/dark rates. Raises
ValueError listing valid keys for an unknown sensorfilter. `gain_mode`
selects the readout gain for detectors that have several (qCMOS: "high"
is the 32x photon-number-resolving mode, "low" the 1x mode); None takes
the wcc_etc config default.
"""
_validate_sensorfilter(sensorfilter)
return Simulation.from_sensorfilter(
sensorfilter, get_scene("G2V", mag=15.0), gain_mode=gain_mode
)
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def saturation_level_e(sensor):
"""Per-frame electron ceiling: min(full well, ADC full scale x gain).
The qCMOS in its 32x high-gain mode clips at the 12-bit ADC, 4095 ADU x
0.1348 e-/ADU = 552 e-, long before the 7500 e- well (#17); in the 1x
low-gain mode (4.132 e-/ADU) the well clips first. Bright fields want
`gain_mode="low"`. Recorded in the FITS header as SATLEVEL.
"""
gain = float(sensor.gain.to(u.electron / u.ct).value)
adc_e = float(sensor.adc_max.to(u.ct).value) * gain
well = sensor.meta.get("well_depth")
return adc_e if well is None else min(float(well), adc_e)
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def get_geometry(sensorfilter, sim=None):
_validate_sensorfilter(sensorfilter)
if sim is None:
sim = make_base_simulation(sensorfilter)
kind = sensorfilter.split(":", 1)[0]
kind = KIND_NAMES.get(kind, kind)
nx, ny = ARRAY_DIMS[kind]
plate_mas = (
sim.sensor.get_plate_scale(sim.telescope).to("arcsec/pix").value * 1000.0
)
return DetectorGeometry(
nx=nx,
ny=ny,
pixel_size_um=float(sim.sensor.pixel_size.value),
plate_scale_mas=plate_mas,
default_focus=FOCUS_WAVES[SENSORFILTER_FOCUS[sensorfilter]],
)