Simple coherence spectrogram

This example shows the time-variation spectrogram of the estimated coherence between the differential-arm length servo control loop error signal for LIGO-Hanford (H1:LSC-DARM_IN1_DQ) and the motion of an optical periscope used to direct the main laser beam into the Hanford interferometer, around the time of GW170814.

gwpy-plot coherencegram \
    --chan H1:LSC-DARM_IN1_DQ H1:PEM-CS_ACC_PSL_PERISCOPE_X_DQ \
    --start 1186741560 \
    --duration 600 \
    --nds2-server nds.gwosc.org \
    --interactive

The same command can be executed directly in Python as:

from gwpy.cli.gwpy_plot import main
main([
    'coherencegram',
    '--chan', 'H1:LSC-DARM_IN1_DQ', 'H1:PEM-CS_ACC_PSL_PERISCOPE_X_DQ',
    '--start', '1186741560',
    '--duration', '600',
    '--nds2-server', 'nds.gwosc.org',
    '--interactive',
])

Program run time: 14.4