v1.2 2014-03-29 - Moved information from comments into definitions for all attributes. - Added source product, orbit number and sclk start/stop times. - Revised some enumerated value options, and corrected some nillable inconsistencies. v1.3.0 2015-01-23 - Updated to version 1.3.0.1 of IM. - Added min/max_observed_event_time. - Included reference_time_UTC as optional attribute for all profile labels. - Revised some definitions. v1.4.0.0 2016-04-25 - Updated to version 1.6.0.0 of IM. - Corrected case errors in class and attribute names and enumerated values - Changed several time attribute types from ASCII_Date_Time_UTC to ASCII_Date_Time_YMD_UTC - revised several definitions - Changed ring_occultation_direction to occultation_direction, and modified the definitions for the values ingress and egress. - Added the class Occultation_Time_Series. - Combined Radio_Occultation and Stellar_Occultation into Occultation_Ring_Profile - Renamed Radio_Occultation_Support to Occultation_Supplement - Removed ring_observation_id and source_pds3_id from all classes except Occultation_Supplement. - Added Schematron rules to make some optional attributes required based on the value of occultation type (e.g., dsn_station_number if occultation_type = radio, sub_stellar_ring_azimuth if occultation_type = stellar). - Reordered some attributes in Occultation_Time_Series. - Reordered some attributes in Occultation_Supplement. v1.5.0.0 2017-03-29 - Changed schema location URLs to https - Updated to version 1.8.0.0 of IM. - Revised definition of pds3_source_id - Corrected the definition of sub_stellar_ring_azimuth - Changed the name of the umbrella class from Occultation to Ring_Moon_Systems - Added Time_Series_Direction This class replaces the Radio_Occultation and Stellar_Occultation classes. It is used for all ring occultation profiles regardless of the occultation type. This class is required for all radio ring occultation calibration and geometry supplemental files. This class supports occultation data organized as a time series. This is an umbrella class for all of the classes and attributes in this dictionary. This class is required for all Rings Node currated data products This section contains the simpleTypes that provide more constraints than those at the base data type level. The simpleTypes defined here build on the base data types. This is another component of the common dictionary and therefore falls within the pds namespace. along_track_timing_offset is a timing offset to the along track spacecraft position. It is the value that minimizes differences in radii of matching circular ring features observed on the ingress and egress sides of the occultation track. Optional in labels for radio occultation. Nillable in which case the nil_reason should be 'inapplicable'. dsn_station_number identifies the receiving DSN station. Required in labels for radio occultations; not used for stellar occultations. Nillable in which case the nil_reason should be 'inapplicable'. earth_received_start_time_utc gives the UTC time corresponding to the earliest time for the data product at which telemetry or other photons were received on Earth. Optional for occultation data. earth_received_stop_time_utc gives the UTC time corresponding to the latest time for the data product at which telemetry or other photons were received on Earth. Optional for occultation data. The frequency_band attribute provides the one or two letter identifier for the frequency band associated with radio occultation data. Required in labels for radio occultations; not used for stellar occultations. highest_detectable_opacity indicates the sensitivity of a ring occultation data set to nearly opaque rings. It specifies the rough value for the largest normal ring opacity that can be detected in the data at the resolution provided, incorporating both statistical effects and calibration uncertainties. Strongly recommended in labels of ring occultation observations. Not intended as a value for a table field. light_source_incidence_angle is an angle measured from the local surface normal vector to the direction of a photon arriving from the light source. For rings, the normal vector is that on the same side of the rings as the light source, so values always range between 0 and 90 in units of degrees. The value is always equal to 90 - | observed_ring_elevation | This will enable users to perform database searches based on the effective ring opening angle when they are not concerned about the the distinction between north-side and southside viewpoints. We have included the 'light source' prefix to the term so that this quantity is not confused with 'incidence angle', a term that is generally associated with sunlight rather than stars or radio transmitters. Required in the label if the value is constant for the observation. If the angle varies for the observation, the min and max attributes are required in the label. Optional as a field in the data table. lowest_detectable_opacity indicates the sensitivity of a ring occultation data set to nearly opaque rings. It specifies the rough value for the smallest normal ring opacity that can be detected in the data at the resolution provided, incorporating both statistical effects and calibration uncertainties. Strongly recommended in labels of ring occultation observations. Not intended as a value for a table field. maximum_light_source_incidence_angle specifes the largest value for observed_ring_elevation in the observation. Only used if the value is not constant over the observation. Values range from 0 to +90 in units of degrees. Not intended for use in the data file. maximum_observed_event_time gives the largest value for observed_event_time in the associated data file. It is given in numeric seconds as an offset from the specified UTC reference time. maximum_observed_event_time is optional in labels since the data file time interval end point values are given by the required start_date_time_utc and stop_date_time_utc attributes in the Time_Coordinates class. maximum_observed_ring_azimuth specifes the largest value for observed_ring_azimuth in the data file. Values range from 0 to 360 in units of degrees. Required in label files for ring occultation data. maximum_observed_ring_elevation specifes the largest value for observed_ring_elevation in the data file. Only used if the value is not constant over the observation. Values range from -90 to +90 in units of degrees. Not intended for use in the data file. maximum_radial_sampling_interval indicates the smallest radial spacing between consecutive points in a ring profile. In practice, this may be somewhat smaller than the radial_resolution because a profile may be over-sampled. If the value of radial_sampling_interval varies, the minimum and maximum attributes are required in labels. Not intended to be used as a table field. maximum_ring_longitude specifies one boundary for the ring longitude range in the data; normally the largest value. However, for ranges that cross the prime meridian, the maximum ring longitude will have a value less than the minimum ring longitude. Values range from 0 to 360 in units of degrees. Required in label files for ring occultation data. maximum_ring_radius indicates the largest ring radius value in the data table. Units are km and are always positive. Required in label files for ring occultation data. maximum_wavelength is the largest wavelength used in the observation. Optional in labels. Used with minimum_wavelength when the observation is over a wavelength range. minimum_light_source_incidence_angle specifes the smallest value for observed_ring_elevation in the observation. Only used if the value is not constant over the observation. Values range from 0 to +90 in units of degrees. Not intended for use in the data file. minimum_observed_event_time gives the smallest value for observed_event_time in the associated data file. It is given in numeric seconds as an offset from the specified UTC reference time. minimum_observed_event_time is optional in labels since the data file time interval end point values are given by the required start_date_time_utc and stop_date_time_utc attributes in the Time_Coordinates class. minimum_observed_ring_azimuth specifes the smallest value for observed_ring_azimuth in the data file. Values range from 0 to 360 in units of degrees. Required in label files for ring occultation data. minimum_observed_ring_elevation specifes the smallest value for observed_ring_elevation in the data file. Only used if the value is not constant over the observation. Values range from -90 to +90 in units of degrees. Not intended for use in the data file. minimum_radial_sampling_interval indicates the smallest radial spacing between consecutive points in a ring profile. In practice, this may be somewhat smaller than the radial_resolution because a profile may be over-sampled. If the value of radial_sampling_interval varies, the minimum and maximum attributes are required in labels. Not intended to be used as a table field. minimum_ring_longitude specifes one boundary for the ring longitude range in the data; normally the smallest value. However, for ranges that cross the prime meridian, the minimum ring longitude will have a value greater than the maximum ring longitude. Values range from 0 to 360 in units of degrees. Required in label files for ring occultation data. minimum_ring_radius indicates the smallest ring radius value in the data table. Units are km and are always positive. Required in label files for ring occultation data. minimum_wavelength is the smallest wavelength used in the observation. Optional in labels. Used with maximum_wavelength when the observation is over a wavelength range. observed_event_start_tdb indicates the value for earliest time in the described data, and is given in elapsed seconds since the J2000 epoch. Optional in labels; not intended for use as a table field. observed_event_start_time_utc indicates the UTC value for earliest time in the described data. It is part of a start/stop pair. If one of observed_event_start_time_utc and observed_event_stop_time_utc is used, both must be used. observed_event_stop_tdb indicates the value for latest time in the described data, and is given in elapsed seconds since the J2000 epoch. Optional in labels; not intended for use as a table field. observed_event_stop_time_utc indicates the UTC value for latest time in the described data. It is part of a start/stop pair. If one of observed_event_start_time_utc and observed_event_stop_time_utc is used, both must be used. observed_ring_elevation is an angle measured at a point in the ring plane, starting from the ring plane to the direction of a photon heading to the observer. This angle is positive on the side of the ring plane defined by positive angular momentum, and negative on the opposite side. Values range from -90 to +90 in units of degrees. This angle is constant for stellar occultations, but may vary significantly during radio occultations. Note: The direction of positive angular momentum points toward the IAU-defined north side of the ring plane for Jupiter, Saturn and Neptune, but IAU-defined south side of the ring plane for Uranus. Required in the label if the value is constant for the observation. If the angle varies for the observation, the min and max attributes are required in the label, and observed_ring_elevation is strongly recommended as a field in the data table. The above definition of observed_ring_elevation is equivalent to the most common usage of the term 'ring open angle', B. occultation_direction indicates the direction of an occultation track. This refers to the observed occultation track overall, not to the subset that might appear in a particular file (e.g., if an occultation includes both ingress and egress tracks, the value for occultation_direction will be both in the data products for each occultation profile. Permitted values are 'ingress', 'egress', 'both', and 'multiple'. The value 'multiple' is only used for some Hubble-based occultations where the occultation track is not monotonic over relatively short time scales. Required in labels of ring occultation observations. Not intended as a value for a table field. occultation_type distinguishes between three types of occultation experiments: stellar, solar, or radio. Stellar occultations involve observing a star as a targeted ring or body passes in front, as seen from either a spacecraft or Earth-based observatory. Solar occultations are similar to stellar occultations except that the Sun is used in place of a star. Radio occultations typically involve observing the continuous-wave radio transmissions from a spacecraft as it passes behind the target as seen from a radio telescope on Earth or another spacecraft. Required in labels of occultation observations. Normally not intended as a value for a table field. orbit_number if present is the value assigned by the mission for the orbit number associated with the observation. Optional in labels of occultation observations and may be used multiple times. Nillable, the nil_reason should be 'inapplicable'. Normally not intended as a value for a table field. The planetary_occultation_flag is a yes-or-no flag that indicates whether a occultation track also intersects the planet. Required in labels of ring occultation observations. Normally not intended as a value for a table field. radial_resolution indicates the nominal radial distance over which changes in ring properties can be detected within a data product. Note: this value may be larger than the radial_sampling_interval value, because a data product can be over-sampled. Required in labels if the value is fixed, as it is for stellar occultations. If the value varies, the corresponding minimum and maximum attributes must be used instead. Not intended to be used as a table field. radial_sampling_interval indicates the radial spacing between consecutive points in a ring profile. In practice, this may be somewhat smaller than the radial_resolution because a profile may be over-sampled. Required in labels if the value is fixed. If the value varies, the corresponding minimum and and maximum attributes must be used instead. Not intended to be used as a table field. reference_time_utc provides a date and time in UTC format. Given in a label when time values in a table are given as elapsed seconds offset from a reference time. Unless there are compelling reasons to do otherwise, reference_time_utc should correspond to the start of a day. Required anytime a table field is given relative to a specific date and time other than when Barycentric Dynamical Time is used (e.g., observed_event_tdb). ring_event_start_tdb indicates the value for earliest time in the described data, and is given in ring_event_tdb format. Optional in labels; not intended for use as a table field. ring_event_start_time_utc gives the UTC time corresponding to the earliest time given by ring_event_time or ring_event_tdb in the data table. ring_event_start_time_utc is required for all ring occultation data. ring_event_start_time_utc is required label attribute for all ring occultation data. ring_event_stop_tdb indicates the value for latest time in the described data, and is given in ring_event_tdb format. Optional in labels; not intended for use as a table field. ring_event_stop_time_utc gives the UTC time corresponding to the latest time given by ring_event_time or ring_event_tdb in the data table. ring_event_stop_time_utc is required for all ring occultation data. ring_event_stop_time_utc is required label attribute for all ring occultation data. The ring_observation_id uniquely identifies a single experiment or observation (image, occultation profile, spectrum, etc.) within a rings-related data set. This is the common id by which data are identified within the Rings Node catalog. It describes the smallest quantity of data that can be usefully cataloged or analyzed by itself. Note that a single observation may be associated with multiple data products (e.g. raw and calibrated versions of an image). Note also that a single data product may be associated with multiple observations (e.g. a single WFPC2 image file containing four different images). A ring observation id is constructed using numbers, upper case letters, forward slash, colon, period, dash, and underscore as follows: p/type/host/inst/time/... where p is a single-letter planet id (one of J, S, U, or N); type is IMG for images, OCC for occultation profile, etc.; host is the instrument host id, inst is the instrument id; time is the observation time as a date or instrument clock count; further information identifying the observation can then be appended as appropriate. Optional in labels. Nillable, in which case the nil_reason should be 'inapplicable'. Examples: J/IMG/VG2/ISS/20693.01/N J/IMG/VG2/ISS/20693.02/W S/IMG/HST/WFPC2/1995-08-10/U2TF020B/PC1 U/OCC/VG2/RSS/1986-01-24/S U/OCC/VG2/RSS/1986-01-24/X N/OCC/VG2/PPS/1989-08-25/SIGMA_SGR ring_profile_direction indicates the radial direction of a ring occultation within a particular data product. Possible values are 'ingress', 'egress', or 'multiple'. The value 'multiple' is only used for some Hubble-based occultations where the occultation track is not monotonic over relatively short time scales. Required in labels of ring occultation observations. Not intended as a value for a table field. sclk_start_time is the value of the spacecraft clock corresponding to the start_date_time given in the label. sclk_stop_time is the value of the spacecraft clock corresponding to the stop_date_time given in the label. source_pds3_id is the PDS3 product identifier for the source product. If the source product has been archived under PDS4, use the Internal_Reference class in the Investigation_Area. source_pds3_id is constructed as PDS3 dataset_id, a colon, then the PDS3 product_id. The acceptable nil_reasons are 'inapplicable' and 'unknown'. spacecraft_event_start_time_utc gives the UTC time corresponding to the earliest time given by spacecraft_event_time in the data table. However, while spacecraft_event_time is given as seconds offset from a reference time, spacecraft_event_start_time_utc is given as a UTC date time. Required in the label for radio occultation data. Not used for stellar occultations. spacecraft_event_stop_time_utc gives the UTC time corresponding to the latest time given by spacecraft_event_time in the data table. However, while spacecraft_event_time is given as seconds offset from a reference time, spacecraft_event_stop_time_utc is given as a UTC date time. Required in the label for radio occultation data. Not used for stellar occultations. spice_filename gives the file name(s) of SPICE files used in the analysis. Only used if the SPICE files cannot be identified using a LID or LIDVID. Otherwise the association is made in the Reference_Class using the Internal_Reference class. Optional in labels for radio occultation. Nillable in which case the nil_reason should be 'inapplicable'. star_name provides the identifying name of star, including the catalog name if necessary. Examples include 'sigma Sgr' and 'SAO 123456' (for star number 123456 in the Smithsonian Astrophysical Observatory catalog). Use 'Sun' for solar occultations. Required in labels for stellar and solar occultations. Not used for radio occultations. sub_stellar_clock_angle is an angle measured at a point in the ring plane, from the direction toward a star to the local radial direction. This angle is projected into the ring plane and measured in the clockwise (retrograde) direction. Equivalently, this is the prograde angle from the local radial direction to the direction toward the star. For stellar occultation data, this angle is equal to (180 - OBSERVED_RING_AZIMUTH) mod 360. It is available only for backward compatibility with previously published Cassini VIMS occultation data analysis; observed_ring_azimuth is the preferred quantity for archiving. sub_stellar_clock_angle is an optional data table field for Cassini VIMS occultation data; not recommended for other occultation data. In a label, the min and max variation attributes are optional for Cassini VIMS occultation data; not recommended for other occultation data. sub_stellar_ring_azimuth is an angle measured at a point in the ring plane, starting from the direction of a photon arriving from a star, and ending at the direction of a local radial vector. This angle is projected into the ring plane and measured in the prograde direction. Values range from 0 to 360 in units of degrees. For stellar occultation data, this angle is equal to (observed_ring_azimuth + 180) mod 360. It is available only for backward compatibility with previously published Cassini UVIS occultation data analysis; observed_ring_azimuth is the preferred quantity for archiving. sub_stellar_ring_azimuth is an optional data table field for Cassini UVIS occultation data; not recommended for other occultation data. In a label, the min and max variation attributes are optional for Cassini UVIS occultation data; not recommended for other occultation data. time_series_direction indicates the direction the occultation proceeds through the target within a particular data product. Possible values are 'ingress', 'egress', 'both' or 'multiple'. The value 'Multiple' is only used for some Hubble-based occultations where the occultation track is not monotonic over relatively short time scales. Not intended as a value for a table field. wavelength of the observation. Optional in labels. If the observation is over a wavelength range, use the corresponding minimum and maximum attributes instead.