imap_processing.spice.geometry.get_spacecraft_to_instrument_spin_phase_offset#
- imap_processing.spice.geometry.get_spacecraft_to_instrument_spin_phase_offset(instrument: SpiceFrame) float#
Get the spin phase offset from the spacecraft to the instrument.
Nominal offset values were determined using Table 1: Nominal Instrument to S/C CS Transformations in document 7516-0011_drw.pdf. That Table defines the angle from the spacecraft y-axis. We add 90-degrees and take the modulus with 360 to get the angle from the spacecraft x-axis. This math is shown in the comments after each key value pair in the dictionary defined in code. The true values differ slightly from the nominal values. True values are derived from the frame definitions in the IMAP frames kernel which uses ground calibration measurements to define the as-built mounting of each instrument. The function in this module, get_instrument_mounting_az_el, was used to retrieve the true azimuth angles from the IMAP frames kernel.
- Parameters:
instrument (SpiceFrame) – Instrument to get the spin phase offset for.
- Returns:
spacecraft_to_instrument_spin_phase_offset – The spin phase offset from the spacecraft to the instrument.
- Return type: