constel.c File Reference

Information on constellation names and boundaries. More...

#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include "aephem.h"

Macros
#define	AE_CONSTEL_N_CON   89
	The number of constellations defined.
#define	AE_CONSTEL_N_GREEK   24
	The number of Greek letters. More...
#define	AE_CONSTEL_N_BOUNDARIES   357
	The number of constellation boundaries defined in ae_constel_boundary.

Functions
void	ae_skip_white (char *p)
	Move a string-pointer past any white space. More...
int	ae_cat_to_constel_index (const char *cat_name, char *full_name, int len)
	Given a catalogue star name, find a star's constellation. More...
int	ae_coord_to_constel_index (double ra, double dec, double epoch)
	Given a sky coordinate, find the constellation it is in. More...

Variables
const char *	ae_constel_name [AE_CONSTEL_N_CON]
	A list of constellation names. More...
char *	ae_greek_letter_name [AE_CONSTEL_N_GREEK]
	A list of the names of Greek letters. More...
long	ae_constel_boundary [4 *AE_CONSTEL_N_BOUNDARIES]
	A definition of constellation boundaries. More...

Detailed Description

Information on constellation names and boundaries.

Macro Definition Documentation

#define AE_CONSTEL_N_GREEK   24

The number of Greek letters.

Referenced by ae_cat_to_constel_index().

Function Documentation

int ae_cat_to_constel_index	(	const char *	cat_name,
		char *	full_name,
		int	len
	)

Given a catalogue star name, find a star's constellation.

Optionally get a full star-constellation name.

Parameters

cat_name	The star name from the catalogue. It should be of the form {2-char Greek letter abbrev.}[-#]{3-char constellation name}({star name}). For example: `beCet(Diphda)', `al-2Lib(Zubenelgen)'.
full_name	For returning an expanded star name; set to NULL if you do not need this.
len	The length of full_name; ignored if full_name is NULL.

Returns

The index of ae_constel_name representing the constellation that this star lives in; or -1 if it cannot be found.

References AE_CONSTEL_N_CON, AE_CONSTEL_N_GREEK, ae_constel_name, ae_greek_letter_name, and ae_skip_white().

int ae_coord_to_constel_index	(	double	ra,
		double	dec,
		double	epoch
	)

Given a sky coordinate, find the constellation it is in.

Parameters

ra	The right ascension.
dec	The declination.
epoch	The Julian date for the ra/dec coordinates.

Returns

The index of ae_constel_name representing the constellation that this coordinate lives in; or -1 if it cannot be found.

References ae_constel_boundary, AE_CONSTEL_N_BOUNDARIES, AE_FROM_J2000, ae_polar_to_rect(), ae_precess(), AE_RTD, and AE_TO_J2000.

void ae_skip_white

(

char *

p

)

Move a string-pointer past any white space.

Parameters

p	A string pointer.

Referenced by ae_cat_to_constel_index().

Variable Documentation

long ae_constel_boundary[4 *AE_CONSTEL_N_BOUNDARIES]

A definition of constellation boundaries.

The array items are:

• lower right ascension, in units of hours times 3600
• upper right ascension, in units of hours times 3600
• lower declination, in units of degrees times 3600
• array index of ae_constel_name corresponding to the constellation

Reference:

• Roman, Nancy Grace, "Identification of a Constellation from a Position" Pub. Astron. Soc. Pac. 99, 695, (1987).

Referenced by ae_coord_to_constel_index().

const char* ae_constel_name[AE_CONSTEL_N_CON]

A list of constellation names.

Cancri is also abbreviated `Cnc'.

Referenced by ae_cat_to_constel_index().

char* ae_greek_letter_name[AE_CONSTEL_N_GREEK]

Initial value:

= {
  "alpha",
  "beta",
  "gamma",
  "delta",
  "epsilon",
  "zeta",
  "eta",
  "theta",
  "iota",
  "kappa",
  "lambda",
  "mu",
  "nu",
  "xi",
  "omicron",
  "pi",
  "rho",
  "sigma",
  "tau",
  "upsilon",
  "phi",
  "chi",
  "psi",
  "omega"
}

A list of the names of Greek letters.

Referenced by ae_cat_to_constel_index().