[PIPE2D-782] Spectra extracted from data used to construct fiberTraces are not flat

Fri, 19 Mar 2021 17:12:36 +0000

If I run the code in constructFiberProfilesTask.py to make new fiberProfiles from a single exposure and then use them to extract the spectra from the same data they should be identically 1.0, but they are not (see ). The code was actually unpacked into this stand-alone fragment from a notebook, but I think it's doing the same thing as the combine method (remove the %matplotlib notebook to run as a python script).

import os
import numpy as np

import matplotlib.pyplot as plt
%matplotlib notebook

import lsst.daf.persistence as dafPersist

# ---------------------------------

base, rerun = "/projects/HSC/PFS/Subaru", os.path.join("rhl", "sunss")

dataDir = os.path.join(base, "rerun", rerun)
calibRoot = os.path.join(base, "CALIB-SuNSS")
butler = dafPersist.Butler(dataDir, calibRoot=calibRoot)

# ---------------------------------

import pfs.drp.stella.buildFiberProfiles 

BuildFiberProfilesTask = pfs.drp.stella.buildFiberProfiles.BuildFiberProfilesTask

config = BuildFiberProfilesTask.ConfigClass()
config.doBlindFind = False
buildFiberProfilesTask = BuildFiberProfilesTask(config)

# ---------------------------------

dataId = dict(visit=46243, spectrograph=1, arm='r')   # domeflat

exp = butler.get("calexp", dataId)
detMap = butler.get("detectorMap", dataId)
pfsConfig = butler.get("pfsConfig", dataId)

results = buildFiberProfilesTask.run(exp, detMap, pfsConfig)
profiles, centers = results.profiles, results.centers

traces = profiles.makeFiberTracesFromDetectorMap(detMap)

spectra0 = traces.extractSpectra(exp.maskedImage)

for i, ss in enumerate(spectra0):
    profiles[ss.fiberId].norm = ss.flux

traces = profiles.makeFiberTracesFromDetectorMap(detMap)

spectra = traces.extractSpectra(exp.maskedImage)

# ---------------------------------

fig = 1; plt.close(fig); fig = plt.figure(fig)

for ss in spectra:
    if 4 < ss.fiberId < 140:
        plt.plot(ss.flux/np.median(ss.flux), alpha=0.5)

plt.ylim(1 + 0.01*np.array([-1, 1]))
plt.xlabel("pixel")
plt.ylabel("Extracted flux")
plt.title(f"{'%(visit)d %(arm)s%(spectrograph)d' % dataId}");

PFS-JIRA

[PIPE2D-782] Spectra extracted from data used to construct fiberTraces are not flat