imap_processing.spice.geometry.get_lo_pivot_boresight

imap_processing.spice.geometry.get_lo_pivot_boresight(pivot_angle: float) → ndarray[tuple[int, ...], dtype[_ScalarType_co]]

Calculate IMAP-Lo boresight direction as a function of pivot angle.

IMAP-Lo has a pivot mechanism that rotates the instrument about its X-axis. The base boresight direction in IMAP_LO_BASE frame is [0, -1, 0] (negative Y). This function rotates that boresight about the X-axis by the specified pivot angle to get the actual boresight direction.

At a pivot angle of 90 degrees, the boresight points in the -Z direction in the IMAP_LO_BASE frame, which corresponds to near-zero off-pointing in the despun (IMAP_DPS) frame.

Parameters:

pivot_angle (float) – The pivot angle in degrees. Nominal value is 90 degrees.

Returns:

boresight – The boresight unit vector (shape (3,)) in the IMAP_LO_BASE frame.

Return type:

np.ndarray