def value_at_diviner_channels(xarr):
    """Return value of xarr at each diviner channel."""
    dwls = [
        3,
        7.8,
        8.25,
        8.55,
        (13 + 23) / 2,
        (25 + 41) / 2,
        (50 + 100) / 2,
        (100 + 400) / 2,
    ]  # [microns]
    return xarr.interp({"wavelength": dwls})