![]() |
SuperNOVAS v1.5
The NOVAS C library, made better
|
Data Structures | |
struct | cat_entry |
Basic astrometric data for any sidereal object located outside the solar system. More... | |
struct | novas_orbital |
Keplerian orbital elements for NOVAS_ORBITAL_OBJECT type. More... | |
struct | novas_orbital_system |
Specification of an orbital system, in which orbital elements are defined. More... | |
struct | object |
Celestial object of interest. More... | |
Macros | |
#define | CAT_ENTRY_INIT |
Initializer for a NOVAS cat_entry structure. | |
#define | NOVAS_AU 1.495978707e+11 |
[m] Astronomical unit (AU). | |
#define | NOVAS_DEFAULT_DISTANCE (1e9 * NOVAS_PARSEC) |
[m] Default distance at which sidereal sources are assumed when not specified otherwise Historically NOVAS placed sources with no parallax at 1 Gpc distance, and so we follow. | |
#define | NOVAS_EARTH_INIT |
object initializer for the planet Earth | |
#define | NOVAS_EMB_INIT |
object initializer for the the Earth-Moon Barycenter (EMB) | |
#define | NOVAS_ID_TYPES |
Number of different Solar-system body ID types enumerated. | |
#define | NOVAS_JUPITER_INIT |
object initializer for the planet Jupiter | |
#define | NOVAS_KMS (NOVAS_KM) |
[m] One km/s in m/s. | |
#define | NOVAS_LIGHT_YEAR ( NOVAS_C * NOVAS_TROPICAL_YEAR_DAYS * NOVAS_DAY ) |
[m] A light-year in meters. | |
#define | NOVAS_MARS_INIT |
object initializer for the planet Mars | |
#define | NOVAS_MERCURY_INIT |
object initializer for the planet Venus | |
#define | NOVAS_MOON_INIT |
object initializer for the Moon | |
#define | NOVAS_NEPTUNE_INIT |
object initializer for the planet Neptune | |
#define | NOVAS_OBJECT_INIT |
Empty object initializer. | |
#define | NOVAS_ORBIT_INIT |
Initializer for novas_orbital for heliocentric orbits using GCRS ecliptic pqrametrization. | |
#define | NOVAS_ORBITAL_SYSTEM_INIT |
Default orbital system initializer for heliocentric GCRS ecliptic orbits. | |
#define | NOVAS_PARSEC ( NOVAS_AU / NOVAS_ARCSEC ) |
[m] A parsec in meters. | |
#define | NOVAS_PLANET_NAMES_INIT |
String array initializer for Major planet names, matching the enum novas_planet. | |
#define | NOVAS_PLUTO_BARYCENTER_INIT |
object initializer for the Pluto system barycenter | |
#define | NOVAS_PLUTO_INIT |
object initializer for the minor planet Pluto | |
#define | NOVAS_SATURN_INIT |
object initializer for the planet Saturn | |
#define | NOVAS_SSB_INIT |
object initializer for the Solar System Barycenter (SSB) | |
#define | NOVAS_SUN_INIT |
object initializer for the Sun | |
#define | NOVAS_SYSTEM_B1950 "B1950" |
The B1950 coordiante system as a string. | |
#define | NOVAS_SYSTEM_FK4 "FK4" |
The 4th catalog (FK4) coordinate system as a string. | |
#define | NOVAS_SYSTEM_FK5 "FK5" |
The 5th catalog (FK5) coordinate system as a string. | |
#define | NOVAS_SYSTEM_HIP "HIP" |
The Hipparcos dataset coordinate system as a string. | |
#define | NOVAS_SYSTEM_ICRS "ICRS" |
The ICRS system as a string. | |
#define | NOVAS_SYSTEM_J2000 "J2000" |
The J2000 coordinate syste, as a string. | |
#define | NOVAS_URANUS_INIT |
object initializer for the planet Uranus | |
#define | NOVAS_VENUS_INIT |
object initializer for the planet Mercury | |
#define | SIZE_OF_CAT_NAME 6 |
Maximum bytes in catalog IDs including string termination. | |
#define | SIZE_OF_OBJ_NAME 50 |
Maximum bytes in object names including string termination. | |
Enumerations | |
enum | novas_id_type { NOVAS_ID_NAIF = 0 , NOVAS_ID_CALCEPH } |
Solar-system body IDs to use as object.number with NOVAS_EPHEM_OBJECT types. More... | |
enum | novas_object_type { NOVAS_PLANET = 0 , NOVAS_EPHEM_OBJECT , NOVAS_CATALOG_OBJECT , NOVAS_ORBITAL_OBJECT } |
The type of astronomical objects distinguied by the NOVAS library. More... | |
enum | novas_planet { NOVAS_SSB = 0 , NOVAS_MERCURY , NOVAS_VENUS , NOVAS_EARTH , NOVAS_MARS , NOVAS_JUPITER , NOVAS_SATURN , NOVAS_URANUS , NOVAS_NEPTUNE , NOVAS_PLUTO , NOVAS_SUN , NOVAS_MOON , NOVAS_EMB , NOVAS_PLUTO_BARYCENTER } |
Enumeration for the 'major planet' numbers in NOVAS to use as the solar-system body number whenever the object type is NOVAS_PLANET. More... | |
enum | novas_transform_type { PROPER_MOTION = 1 , PRECESSION , CHANGE_EPOCH , CHANGE_J2000_TO_ICRS , CHANGE_ICRS_TO_J2000 } |
The types of coordinate transformations available for tranform_cat(). More... | |
Functions | |
short | make_cat_entry (const char *restrict name, const char *restrict catalog, long cat_num, double ra, double dec, double pm_ra, double pm_dec, double parallax, double rad_vel, cat_entry *source) |
Fully populates the data structure for a catalog source, such as a star, with all parameters provided at once. | |
int | make_cat_object (const cat_entry *star, object *source) |
Populates and object data structure with the data for a catalog source. | |
int | make_cat_object_sys (const cat_entry *star, const char *restrict system, object *source) |
Populates and object data structure with the data for a catalog source for a given system of catalog coordinates. | |
int | make_ephem_object (const char *name, long num, object *body) |
Sets a celestial object to be a Solar-system ephemeris body. | |
int | make_orbital_object (const char *name, long num, const novas_orbital *orbit, object *body) |
Sets a celestial object to be a Solar-system orbital body. | |
int | make_planet (enum novas_planet num, object *restrict planet) |
Sets a celestial object to be a major planet, or the Sun, Moon, Solar-system Barycenter, etc. | |
int | make_redshifted_cat_entry (const char *name, double ra, double dec, double z, cat_entry *source) |
Populates a celestial object data structure with the parameters for a redhifted catalog source, such as a distant quasar or galaxy. | |
int | make_redshifted_object (const char *name, double ra, double dec, double z, object *source) |
Populates a celestial object data structure with the ICRS astrometric parameters for a redhifted catalog source, such as a distant quasar or galaxy. | |
int | make_redshifted_object_sys (const char *name, double ra, double dec, const char *restrict system, double z, object *source) |
Populates a celestial object data structure with the parameters for a redhifted catalog source, such as a distant quasar or galaxy, for a given system of catalog coordinates. | |
enum novas_planet | naif_to_novas_planet (long id) |
Converts a NAIF ID to a NOVAS major planet ID. | |
void | novas_case_sensitive (int value) |
Enables or disables case-sensitive processing of the object name. | |
int | novas_init_cat_entry (cat_entry *restrict source, const char *restrict name, double ra, double dec) |
Initializes a catalog entry, such as a star or a distant galaxy, with a name and coordinates. | |
int | novas_make_moon_orbit (double jd_tdb, novas_orbital *restrict orbit) |
Gets the current orbital elements for the Moon relative to the geocenter for the specified epoch of observation. | |
int | novas_make_planet_orbit (enum novas_planet id, double jd_tdb, novas_orbital *restrict orbit) |
Get approximate current heliocentric orbital elements for the major planets. | |
int | novas_orbit_posvel (double jd_tdb, const novas_orbital *restrict orbit, enum novas_accuracy accuracy, double *restrict pos, double *restrict vel) |
Calculates a rectangular equatorial position and velocity vector for the given orbital elements for the specified time of observation. | |
enum novas_planet | novas_planet_for_name (const char *restrict name) |
Returns the NOVAS planet ID for a given name (case insensitive), or -1 if no match is found. | |
int | novas_set_catalog (cat_entry *restrict source, const char *restrict catalog, long num) |
Sets the optional catalog information for a sidereal source. | |
int | novas_set_distance (cat_entry *source, double parsecs) |
Sets the distance for a catalog source. | |
int | novas_set_lsr_vel (cat_entry *source, double epoch, double v_kms) |
Sets a radial velocity for a catalog source, defined w.r.t. | |
int | novas_set_orbsys_pole (enum novas_reference_system type, double ra, double dec, novas_orbital_system *restrict sys) |
Sets the orientation of an orbital system using the RA and DEC coordinates of the pole of the Laplace (or else equatorial) plane relative to which the orbital elements are defined. | |
int | novas_set_parallax (cat_entry *source, double mas) |
Sets the parallax (a measure of distance) for a catalog source. | |
int | novas_set_proper_motion (cat_entry *source, double pm_ra, double pm_dec) |
Sets the proper-motion for a (Galactic) catalog source. | |
int | novas_set_redshift (cat_entry *source, double z) |
Sets a redhift for a catalog source, as a relativistic measure of velocity. | |
int | novas_set_ssb_vel (cat_entry *source, double v_kms) |
Sets a radial velocity for a catalog source, defined w.r.t. | |
long | novas_to_dexxx_planet (enum novas_planet id) |
Converts a NOVAS Solar-system body ID to a NAIF Solar-system body ID for DExxx ephemeris files. | |
long | novas_to_naif_planet (enum novas_planet id) |
Converts a NOVAS Solar-system body ID to a NAIF Solar-system body ID. | |
int | proper_motion (double jd_tdb_in, const double *pos, const double *restrict vel, double jd_tdb_out, double *out) |
Applies proper motion, including foreshortening effects, to a star's position. | |
int | starvectors (const cat_entry *restrict star, double *restrict pos, double *restrict motion) |
Converts angular quantities for stars to vectors. | |
short | transform_cat (enum novas_transform_type, double jd_tt_in, const cat_entry *in, double jd_tt_out, const char *out_id, cat_entry *out) |
Transform a star's catalog quantities for a change the coordinate system and/or the date for which the positions are calculated. | |
int | transform_hip (const cat_entry *hipparcos, cat_entry *hip_2000) |
Convert Hipparcos catalog data at epoch J1991.25 to epoch J2000.0, for use within NOVAS. | |
#define NOVAS_AU 1.495978707e+11 |
#define NOVAS_DEFAULT_DISTANCE (1e9 * NOVAS_PARSEC) |
[m] Default distance at which sidereal sources are assumed when not specified otherwise Historically NOVAS placed sources with no parallax at 1 Gpc distance, and so we follow.
#define NOVAS_EARTH_INIT |
#define NOVAS_EMB_INIT |
#define NOVAS_ID_TYPES |
#define NOVAS_JUPITER_INIT |
#define NOVAS_KMS (NOVAS_KM) |
[m] One km/s in m/s.
#define NOVAS_LIGHT_YEAR ( NOVAS_C * NOVAS_TROPICAL_YEAR_DAYS * NOVAS_DAY ) |
[m] A light-year in meters.
#define NOVAS_MARS_INIT |
#define NOVAS_MERCURY_INIT |
#define NOVAS_MOON_INIT |
#define NOVAS_NEPTUNE_INIT |
#define NOVAS_OBJECT_INIT |
#define NOVAS_ORBIT_INIT |
Initializer for novas_orbital for heliocentric orbits using GCRS ecliptic pqrametrization.
#define NOVAS_ORBITAL_SYSTEM_INIT |
Default orbital system initializer for heliocentric GCRS ecliptic orbits.
#define NOVAS_PARSEC ( NOVAS_AU / NOVAS_ARCSEC ) |
[m] A parsec in meters.
#define NOVAS_PLANET_NAMES_INIT |
String array initializer for Major planet names, matching the enum novas_planet.
E.g.
#define NOVAS_PLUTO_BARYCENTER_INIT |
#define NOVAS_PLUTO_INIT |
#define NOVAS_SATURN_INIT |
#define NOVAS_SSB_INIT |
#define NOVAS_SUN_INIT |
#define NOVAS_SYSTEM_B1950 "B1950" |
The B1950 coordiante system as a string.
#define NOVAS_SYSTEM_FK4 "FK4" |
The 4th catalog (FK4) coordinate system as a string.
#define NOVAS_SYSTEM_FK5 "FK5" |
The 5th catalog (FK5) coordinate system as a string.
#define NOVAS_SYSTEM_HIP "HIP" |
The Hipparcos dataset coordinate system as a string.
#define NOVAS_SYSTEM_ICRS "ICRS" |
The ICRS system as a string.
#define NOVAS_SYSTEM_J2000 "J2000" |
The J2000 coordinate syste, as a string.
#define NOVAS_URANUS_INIT |
#define NOVAS_VENUS_INIT |
#define SIZE_OF_CAT_NAME 6 |
Maximum bytes in catalog IDs including string termination.
#define SIZE_OF_OBJ_NAME 50 |
Maximum bytes in object names including string termination.
enum novas_id_type |
Solar-system body IDs to use as object.number with NOVAS_EPHEM_OBJECT types.
JPL ephemerides use NAIF IDs to identify objects in the Solar-system, which is thus the most widely adopted convention for numbering Solar-system bodies. But other numbering systems also exists, for example the CALCEPH library uses its own convention for the numbering of asteroids.
Enumerator | |
---|---|
NOVAS_ID_NAIF | If the ephemeris provider should use NAIF IDs. |
NOVAS_ID_CALCEPH | If the ephemeris provider should use CALCEPH IDs. |
enum novas_object_type |
The type of astronomical objects distinguied by the NOVAS library.
Enumerator | |
---|---|
NOVAS_PLANET | A major planet, or else the Sun, the Moon, or the Solar-System Barycenter (SSB).
|
NOVAS_EPHEM_OBJECT | A Solar-system body that does not fit the major planet type, and requires specific user-provided novas_ephem_provider implementation.
|
NOVAS_CATALOG_OBJECT | Any non-solar system object that may be handled via 'catalog' coordinates, such as a star or a quasar. |
NOVAS_ORBITAL_OBJECT | Any Solar-system body, whose position is determined by a set of orbital elements.
|
enum novas_planet |
Enumeration for the 'major planet' numbers in NOVAS to use as the solar-system body number whenever the object type is NOVAS_PLANET.
enum novas_transform_type |
The types of coordinate transformations available for tranform_cat().
short make_cat_entry | ( | const char *restrict | name, |
const char *restrict | catalog, | ||
long | cat_num, | ||
double | ra, | ||
double | dec, | ||
double | pm_ra, | ||
double | pm_dec, | ||
double | parallax, | ||
double | rad_vel, | ||
cat_entry * | source ) |
Fully populates the data structure for a catalog source, such as a star, with all parameters provided at once.
Alternatively, you may use novas_init_cat_entry()
to initialize just with the name and R.A./Dec coordinates, and then add further information step-by-step as needed, icluding using alternative parameters (SSB vs. LSR velocity, vs. redshift; parallax vs. distance). The latter approach provides more flexibility, and will result in more readable code, which is also easier to debug.
name | Object name (less than SIZE_OF_OBJ_NAME in length). It may be NULL if not relevant. | |
catalog | Catalog identifier or epoch (less than SIZE_OF_CAT_NAME in length). E.g. 'HIP' for Hipparcos, 'TY2' for Tycho-2; or 'ICRS', 'B1950', 'J2000'. It may be NULL if not relevant. | |
cat_num | Object number in the catalog. It is not used internally, so you may set it to anything that is meaningful to you, or set it to 0 as a default. | |
ra | [h] Right ascension of the object. | |
dec | [deg] Declination of the object. | |
pm_ra | [mas/yr] Proper motion in right ascension. | |
pm_dec | [mas/yr] Proper motion in declination. | |
parallax | [mas] Parallax. | |
rad_vel | [km/s] Radial velocity relative to the Solar-System Barycenter (SSB). To convert velocities defined against the Local Standard of Rest (LSR), you may use novas_lsr_to_ssb_vel() to convert appropriately. Or, to convert from a redshift value, you might use novas_z2v() . | |
[out] | source | Pointer to data structure to populate. |
References novas_init_cat_entry(), novas_set_catalog(), novas_set_parallax(), novas_set_proper_motion(), novas_set_ssb_vel(), and rad_vel().
Populates and object data structure with the data for a catalog source.
The astrometric parameters must be defined with ICRS. To create objects in other reference systems, use make_cat_object_sys()
instead.
star | Pointer to structure to populate with the catalog data for a celestial object located outside the solar system, specified with ICRS astrometric parameters. | |
[out] | source | Pointer to the celestial object data structure to be populated. |
References make_object(), NOVAS_CATALOG_OBJECT, cat_entry::starname, and cat_entry::starnumber.
Populates and object data structure with the data for a catalog source for a given system of catalog coordinates.
star | Pointer to structure to populate with the catalog data for a celestial object located outside the solar system. | |
system | Input catalog coordinate system epoch, e.g. "ICRS", "B1950.0", "J2000.0", "FK4", "FK5", or "HIP". In general, any Besselian or Julian year epoch can be used by year (e.g. "B1933.193" or "J2022.033"), or else the fixed value listed. If 'B' or 'J' is ommitted in front of the epoch year, then Besselian epochs are assumed prior to 1984.0. (See ‘novas_epoch() for more). | |
[out] | source | Pointer to the celestial object data structure to be populated with the corresponding ICRS catalog coordinates, after appying proper-motion and precession corrections as appropriate. |
References make_cat_object(), and object::star.
int make_ephem_object | ( | const char * | name, |
long | num, | ||
object * | body ) |
Sets a celestial object to be a Solar-system ephemeris body.
Typically this would be used to define minor planets, asteroids, comets and planetary satellites.
name | Name of object. By default converted to upper-case, unless novas_case_sensitive() was called with a non-zero argument. Max. SIZE_OF_OBJ_NAME long, including termination. If the ephemeris provider uses names, then the name should match those of the ephemeris provider – otherwise it is not important. | |
num | Solar-system body ID number (e.g. NAIF). The number should match the needs of the ephemeris provider used with NOVAS. (If the ephemeris provider is by name and not ID number, then the number here is not important). | |
[out] | body | Pointer to structure to populate. |
References make_object(), and NOVAS_EPHEM_OBJECT.
int make_orbital_object | ( | const char * | name, |
long | num, | ||
const novas_orbital * | orbit, | ||
object * | body ) |
Sets a celestial object to be a Solar-system orbital body.
Typically this would be used to define minor planets, asteroids, comets, or even planetary satellites.
name | Name of object. It may be NULL if not relevant. | |
num | Solar-system body ID number (e.g. NAIF). It is not required and can be set e.g. to -1 if not relevant to the caller. | |
orbit | The orbital parameters to adopt. The data will be copied, not referenced. | |
[out] | body | Pointer to structure to populate. |
References make_object(), NOVAS_ORBITAL_OBJECT, and object::orbit.
int make_planet | ( | enum novas_planet | num, |
object *restrict | planet ) |
Sets a celestial object to be a major planet, or the Sun, Moon, Solar-system Barycenter, etc.
num | Planet ID number (NOVAS convention) | |
[out] | planet | Pointer to structure to populate. |
References make_object(), NOVAS_PLANET, NOVAS_PLANET_NAMES_INIT, and NOVAS_PLANETS.
int make_redshifted_cat_entry | ( | const char * | name, |
double | ra, | ||
double | dec, | ||
double | z, | ||
cat_entry * | source ) |
Populates a celestial object data structure with the parameters for a redhifted catalog source, such as a distant quasar or galaxy.
It is similar to make_cat_object()
except that it takes a Doppler-shift (z) instead of radial velocity and it assumes no parallax and no proper motion (appropriately for a distant redshifted source). The catalog name is set to EXT
to indicate an extragalactic source, and the catalog number defaults to 0. The user may change these default field values as appropriate afterwards, if necessary.
name | Object name (less than SIZE_OF_OBJ_NAME in length). It may be NULL. | |
ra | [h] Right ascension of the object (hours). | |
dec | [deg] Declination of the object (degrees). | |
z | Redhift value (λobs / λrest - 1 = frest / fobs - 1). | |
[out] | source | Pointer to structure to populate. |
References novas_init_cat_entry(), novas_set_catalog(), and novas_set_redshift().
int make_redshifted_object | ( | const char * | name, |
double | ra, | ||
double | dec, | ||
double | z, | ||
object * | source ) |
Populates a celestial object data structure with the ICRS astrometric parameters for a redhifted catalog source, such as a distant quasar or galaxy.
To create redshifted objects with in other reference systems, use make_redshifted_object_sys()
instead.
It is similar to make_cat_object()
except that it takes a Doppler-shift (z) instead of radial velocity and it assumes no parallax and no proper motion (appropriately for a distant redshifted source). The catalog name is set to EXT
to indicate an extragalactic source, and the catalog number defaults to 0. The user may change these default field values as appropriate afterwards, if necessary.
name | Object name (less than SIZE_OF_OBJ_NAME in length). It may be NULL. | |
ra | [h] ICRS Right ascension of the object (hours). | |
dec | [deg] ICRS Declination of the object (degrees). | |
z | Redhift value (λobs / λrest - 1 = frest / fobs - 1). | |
[out] | source | Pointer to structure to populate. |
References make_cat_object(), and make_redshifted_cat_entry().
int make_redshifted_object_sys | ( | const char * | name, |
double | ra, | ||
double | dec, | ||
const char *restrict | system, | ||
double | z, | ||
object * | source ) |
Populates a celestial object data structure with the parameters for a redhifted catalog source, such as a distant quasar or galaxy, for a given system of catalog coordinates.
name | Object name (less than SIZE_OF_OBJ_NAME in length). It may be NULL. | |
ra | [h] ICRS Right ascension of the object (hours). | |
dec | [deg] ICRS Declination of the object (degrees). | |
system | Input catalog coordinate system epoch, e.g. "ICRS", "B1950.0", "J2000.0", "FK4", "FK5", or "HIP". In general, any Besselian or Julian year epoch can be used by year (e.g. "B1933.193" or "J2022.033"), or else the fixed value listed. If 'B' or 'J' is ommitted in front of the epoch year, then Besselian epochs are assumed prior to 1984.0. | |
z | Redhift value (λobs / λrest - 1 = frest / fobs - 1). | |
[out] | source | Pointer to the celestial object data structure to be populated with the corresponding ICRS catalog coordinates. |
References make_redshifted_object(), and object::star.
enum novas_planet naif_to_novas_planet | ( | long | id | ) |
Converts a NAIF ID to a NOVAS major planet ID.
It account for the different IDs used for Sun, Moon, SSB, EMB and the Pluto system. Otherwise NAIF planet barycenters are mapped to the corresponding bodies. NAIF body centers n99 (e.g. 399 for Earth) are mapped to the corresponding NOVAS planet number n. All other NAIF IDs will return -1, indicating no match to a NOVAS planet ID.
id | The NAIF ID of the major planet of interest |
References NOVAS_EMB, NOVAS_MERCURY, NOVAS_MOON, NOVAS_PLUTO, NOVAS_PLUTO_BARYCENTER, NOVAS_SSB, and NOVAS_SUN.
void novas_case_sensitive | ( | int | value | ) |
Enables or disables case-sensitive processing of the object name.
The effect is not retroactive. The setting will only affect the celestial objects that are defined after the call. Note, that catalog names, set via make_cat_entry() are always case sensitive regardless of this setting.
value | (boolean) TRUE (non-zero) to enable case-sensitive object names, or else FALSE (0) to convert names to upper case only (NOVAS C compatible behavior). |
int novas_init_cat_entry | ( | cat_entry *restrict | source, |
const char *restrict | name, | ||
double | ra, | ||
double | dec ) |
Initializes a catalog entry, such as a star or a distant galaxy, with a name and coordinates.
All other fields of the cat_entry
structure will be initialized with zeroes. After the initialization, you may set further properties, such as:
The typical process for setting up a catalog source is captured by the following steps:
cat_entry
with source name and RA / Dec coordinates using novas_init_cat_entry()
.novas_set_ssb_vel()
, ornovas_set_lsr_vel()
, ornovas_set_redshift()
.novas_set_proper_motion()
.novas_set_parallax()
, ornovas_set_distance()
.novas_set_catalog()
.After the initialization (Step 1), order does not matter.
[out] | source | Output structure to populate. |
name | Object name (less than SIZE_OF_OBJ_NAME in length). It may be NULL if not relevant. | |
ra | [h] Right ascension of the object. | |
dec | [deg] Declination of the object. |
References SIZE_OF_OBJ_NAME.
int novas_make_moon_orbit | ( | double | jd_tdb, |
novas_orbital *restrict | orbit ) |
Gets the current orbital elements for the Moon relative to the geocenter for the specified epoch of observation.
REFERENCES:
jd_tdb | [day] Barycentric Dynamical Time (TDB) based Julian Date. | |
[out] | orbit | Orbital elements data structure to populate. |
errno
set to EINVAL
).References NOVAS_AU, NOVAS_EARTH, NOVAS_JD_J2000, NOVAS_ORBIT_INIT, and TWOPI.
int novas_make_planet_orbit | ( | enum novas_planet | id, |
double | jd_tdb, | ||
novas_orbital *restrict | orbit ) |
Get approximate current heliocentric orbital elements for the major planets.
These orbital elements are not suitable for precise position velocity calculations, but they may be useful to obtain approximate positions for the major planets, e.g. to estimate rise or set times, or apparent elevation angles from an observing site.
These orbitals can provide planet positions to arcmin-level precision for the rocky inner planets, and to a fraction of a degree precision for the gas and ice giants and Pluto. The accuracies for Uranus, Neptune, and Pluto are significantly improved (to the arcmin level) if used in the time range of 1800 AD to 2050 AD. For a more detailed summary of the typical accuracies, see either of the references below.
NOTES:
REFERENCES:
id | NOVAS major planet ID. All major planets, except Earth, are supported. The Earth-Moon Barycenter (EMB), and Pluto system Barycenter are supported also. (For Pluto, the Pluto System Barycenter values are returned.) | |
jd_tdb | [day] Barycentric Dynamical Time (TDB) based Julian Date. | |
[out] | orbit | Orbital elements data structure to populate. |
errno
set to EINVAL
).Keplerian orbital elements at J2000 from Table 8.10.2 of E.M. Standish and J.G. Williams 1992, valid for 1800 AD to 2050 AD.
Temporal evolution of the Keplerian orbital elements from Table 8.10.2 of E.M. Standish and J.G. Williams 1992, valid for 1800 AD to 2050 AD.
Keplerian orbital elements at J2000 from Table 8.10.3 of E.M. Standish and J.G. Williams 1992, valid for 3000 BC to 3000 AD.
Temporal evolution of the Keplerian orbital elements from Table 8.10.3 of E.M. Standish and J.G. Williams 1992, vaid for 3000 BC to 3000 AD.
Additional terms for computing M for the outer planets (Jupiter and beyond) from Table 8.10.4 of E.M. Standish and J.G. Williams 1992.
References NOVAS_EARTH, NOVAS_EMB, NOVAS_JD_J2000, NOVAS_JUPITER, NOVAS_ORBIT_INIT, NOVAS_PLUTO, NOVAS_PLUTO_BARYCENTER, and TWOPI.
int novas_orbit_posvel | ( | double | jd_tdb, |
const novas_orbital *restrict | orbit, | ||
enum novas_accuracy | accuracy, | ||
double *restrict | pos, | ||
double *restrict | vel ) |
Calculates a rectangular equatorial position and velocity vector for the given orbital elements for the specified time of observation.
REFERENCES:
jd_tdb | [day] Barycentric Dynamic Time (TDB) based Julian date | |
orbit | Orbital parameters | |
accuracy | NOVAS_FULL_ACCURACY (0) or NOVAS_REDUCED_ACCURACY (1). | |
[out] | pos | [AU] Output ICRS equatorial position vector around orbital center, or NULL if not required. |
[out] | vel | [AU/day] Output ICRS equatorial velocity vector rel. to orbital center, or NULL if not required. |
References novas_orbit_native_posvel().
enum novas_planet novas_planet_for_name | ( | const char *restrict | name | ) |
Returns the NOVAS planet ID for a given name (case insensitive), or -1 if no match is found.
name | The planet name, or that for the "Sun", "Moon" or "SSB" (case insensitive). The spelled out "Solar System Barycenter" is also recognized with either spaces, hyphens ('-') or underscores ('_') separating the case insensitive words. |
References NOVAS_PLANET_NAMES_INIT, NOVAS_PLANETS, and NOVAS_SSB.
int novas_set_catalog | ( | cat_entry *restrict | source, |
const char *restrict | catalog, | ||
long | num ) |
Sets the optional catalog information for a sidereal source.
SuperNOVAS does not use the catalog information internally. It is entirely for the convenience of the user to set these values if it is useful to them.
[out] | source | Output structure to populate with the parameters. |
catalog | Catalog identifier or epoch (less than SIZE_OF_CAT_NAME in length). E.g. 'HIP' for Hipparcos, 'TY2' for Tycho-2; or 'ICRS', 'B1950', 'J2000'. It may be NULL if not relevant. | |
num | Object's number in catalog. |
References SIZE_OF_CAT_NAME.
int novas_set_distance | ( | cat_entry * | source, |
double | parsecs ) |
Sets the distance for a catalog source.
[out] | source | Output structure to populate with the parameters. |
parsecs | [pc] distance |
References novas_set_parallax().
int novas_set_lsr_vel | ( | cat_entry * | source, |
double | epoch, | ||
double | v_kms ) |
Sets a radial velocity for a catalog source, defined w.r.t.
the Local Standard of Rest (LSR).
[out] | source | Output structure to populate with the parameters. |
v_kms | [km/s] Radial velocity of source w.r.t. the Local Standard of Rest (LSR). | |
epoch | [yr] Coordinate epoch. |
References cat_entry::dec, novas_lsr_to_ssb_vel(), novas_set_ssb_vel(), and cat_entry::ra.
int novas_set_orbsys_pole | ( | enum novas_reference_system | type, |
double | ra, | ||
double | dec, | ||
novas_orbital_system *restrict | sys ) |
Sets the orientation of an orbital system using the RA and DEC coordinates of the pole of the Laplace (or else equatorial) plane relative to which the orbital elements are defined.
Orbital parameters of planetary satellites normally include the R.A. and declination of the pole of the local Laplace plane in which the Keplerian orbital elements are referenced.
The system will become referenced to the equatorial plane, the relative obliquity is set to (90° - dec
), while the argument of the ascending node ('Omega') is set to (90° + ra
).
NOTES:
type | Coordinate reference system in which ra and dec are defined (e.g. NOVAS_GCRS). | |
ra | [h] the R.A. of the pole of the oribtal reference plane. | |
dec | [deg] the declination of the pole of the oribtal reference plane. | |
[out] | sys | Orbital system |
sys
pointer is NULL.References NOVAS_EQUATORIAL_PLANE, and NOVAS_TIRS.
int novas_set_parallax | ( | cat_entry * | source, |
double | mas ) |
Sets the parallax (a measure of distance) for a catalog source.
[out] | source | Output structure to populate with the parameters. |
mas | [mas] Parallax |
References cat_entry::parallax.
int novas_set_proper_motion | ( | cat_entry * | source, |
double | pm_ra, | ||
double | pm_dec ) |
Sets the proper-motion for a (Galactic) catalog source.
[out] | source | Output structure to populate with the parameters. |
pm_ra | [mas/yr] Proper motion in right ascension. | |
pm_dec | [mas/yr] Proper motion in declination. |
References cat_entry::promodec, and cat_entry::promora.
int novas_set_redshift | ( | cat_entry * | source, |
double | z ) |
Sets a redhift for a catalog source, as a relativistic measure of velocity.
[out] | source | Output structure to populate with the parameters. |
z | [-1:inf] The redshift measure z, defined as (1 + z) = sqrt((1 + v/_c_) / (1 - v/_c_)) |
References novas_set_ssb_vel(), and novas_z2v().
int novas_set_ssb_vel | ( | cat_entry * | source, |
double | v_kms ) |
Sets a radial velocity for a catalog source, defined w.r.t.
the Solar-System Barycenter (SSB).
[out] | source | Output structure to populate with the parameters. |
v_kms | [km/s] Radial velocity of source w.r.t. the Solar-System Barycenter (SSB). |
References NOVAS_C, and cat_entry::radialvelocity.
long novas_to_dexxx_planet | ( | enum novas_planet | id | ) |
Converts a NOVAS Solar-system body ID to a NAIF Solar-system body ID for DExxx ephemeris files.
The DExxx (e.g. DE440) ephemeris files use NAIF IDs, but for most planets contain barycentric data only rather than that of the planet center. For Earth-based observations, it only really makes a difference whether the 3 is used for the Earth-Moon Barycenter (EMB) or 399 for the geocenter.
id | The NOVAS ID of the major planet of interest |
References NOVAS_EARTH, NOVAS_EMB, NOVAS_MERCURY, NOVAS_MOON, NOVAS_PLUTO, NOVAS_PLUTO_BARYCENTER, NOVAS_SSB, and NOVAS_SUN.
long novas_to_naif_planet | ( | enum novas_planet | id | ) |
Converts a NOVAS Solar-system body ID to a NAIF Solar-system body ID.
NOVAS and NAIF use slightly different IDs for major planets, the Moon, SSB, EMB, and the Pluto system. In NOVAS, major planets are have IDs ranging from 1 through 9, but for NAIF 1–9 are the planetary barycenters and the planet centers have numbers in the hundreds ending with 99 (e.g. the center of Earth is NAIF 399; 3 is the NOVAS ID for Earth and the NAIF ID for the Earth-Moon Barycenter [EMB]). The Sun and Moon also have distinct IDs in NAIF vs NOVAS.
id | The NOVAS ID of the major planet of interest |
References NOVAS_EMB, NOVAS_MERCURY, NOVAS_MOON, NOVAS_PLUTO, NOVAS_PLUTO_BARYCENTER, NOVAS_SSB, and NOVAS_SUN.
int proper_motion | ( | double | jd_tdb_in, |
const double * | pos, | ||
const double *restrict | vel, | ||
double | jd_tdb_out, | ||
double * | out ) |
Applies proper motion, including foreshortening effects, to a star's position.
REFERENCES:
jd_tdb_in | [day] Barycentric Dynamical Time (TDB) based Julian date of the first epoch. | |
pos | [AU] Position vector at first epoch. | |
vel | [AU/day] Velocity vector at first epoch. | |
jd_tdb_out | [day] Barycentric Dynamical Time (TDB) based Julian date of the second epoch. | |
[out] | out | Position vector at second epoch. It can be the same vector as the input. |
int starvectors | ( | const cat_entry *restrict | star, |
double *restrict | pos, | ||
double *restrict | motion ) |
Converts angular quantities for stars to vectors.
NOTES:
REFERENCES:
star | Pointer to catalog entry structure containing ICRS catalog | |
[out] | pos | [AU] Position vector, equatorial rectangular coordinates, It may be NULL if not required. |
[out] | motion | [AU/day] Perceived motion of star, in equatorial rectangular coordinates. It must be distinct from the pos output vector, and may be NULL if not required. Note, that it is suitable only for calculating the apparent 3D location of the star at a different time, and should not be used as a measure of physical velocity, e.g. for spectroscopic radial velocity determination. |
References NOVAS_KMS, novas_los_to_xyz(), and radec2vector().
short transform_cat | ( | enum novas_transform_type | option, |
double | jd_tt_in, | ||
const cat_entry * | in, | ||
double | jd_tt_out, | ||
const char * | out_id, | ||
cat_entry * | out ) |
Transform a star's catalog quantities for a change the coordinate system and/or the date for which the positions are calculated.
Also used to rotate catalog quantities on the dynamical equator and equinox of J2000.0 to the ICRS or vice versa.
'date_incat' and 'date_newcat' may be specified either as a Julian date (e.g., 2433282.5 or NOVAS_JD_B1950) or a fractional Julian year and fraction (e.g., 1950.0). Values less than 10000 are assumed to be years. You can also use the supplied constants NOVAS_JD_J2000 or NOVAS_JD_B1950. The date arguments are ignored for the ICRS frame conversion options.
If 'option' is PROPER_MOTION (1), input data can be in any reference system. If 'option' is PRECESSION (2) or CHANGE_EPOCH (3), input data is assume to be in the dynamical system of 'date_incat' and produces output in the dynamical system of 'date_outcat'. If 'option' is CHANGE_J2000_TO_ICRS (4), the input data should be in the J2000.0 dynamical frame. And if 'option' is CHANGE_ICRS_TO_J2000 (5), the input data must be in the ICRS, and the output will be in the J2000 dynamical frame.
This function cannot be properly used to bring data from old star catalogs into the modern system, because old catalogs were compiled using a set of constants that are incompatible with modern values. In particular, it should not be used for catalogs whose positions and proper motions were derived by assuming a precession constant significantly different from the value implicit in function precession().
option | Type of transformation | |
jd_tt_in | [day|yr] Terrestrial Time (TT) based Julian date, or year, of input catalog data. Not used if option is CHANGE_J2000_TO_ICRS (4) or CHANGE_ICRS_TO_J2000 (5). | |
in | An entry from the input catalog, with units as given in the struct definition | |
jd_tt_out | [day|yr] Terrestrial Time (TT) based Julian date, or year, of output catalog data. Not used if option is CHANGE_J2000_TO_ICRS (4) or CHANGE_ICRS_TO_J2000 (5). | |
out_id | Catalog identifier (0 terminated). It may also be NULL in which case the catalog name is inherited from the input. | |
[out] | out | The transformed catalog entry, with units as given in the struct definition. It may be the same as the input. |
References cat_entry::catalog, CHANGE_EPOCH, CHANGE_ICRS_TO_J2000, CHANGE_J2000_TO_ICRS, cat_entry::dec, frame_tie(), ICRS_TO_J2000, J2000_TO_ICRS, NOVAS_JD_J2000, NOVAS_KMS, novas_los_to_xyz(), novas_vlen(), novas_xyz_to_los(), cat_entry::parallax, PRECESSION, precession(), cat_entry::promodec, cat_entry::promora, PROPER_MOTION, cat_entry::ra, radec2vector(), cat_entry::radialvelocity, SIZE_OF_CAT_NAME, SIZE_OF_OBJ_NAME, cat_entry::starname, and cat_entry::starnumber.
Convert Hipparcos catalog data at epoch J1991.25 to epoch J2000.0, for use within NOVAS.
To be used only for Hipparcos or Tycho stars with linear space motion. Both input and output data is in the ICRS.
hipparcos | An entry from the Hipparcos catalog, at epoch J1991.25, with 'ra' in degrees(!) as per Hipparcos catalog units. | |
[out] | hip_2000 | The transformed input entry, at epoch J2000.0, with 'ra' in hours(!) as per the NOVAS convention. It may be the same as the input. |
References cat_entry::catalog, NOVAS_JD_HIP, PROPER_MOTION, cat_entry::ra, and transform_cat().