Macros
#define	NOVAS_ARCMIN (NOVAS_DEGREE / 60.0)
	[rad] An arc minute expressed in radians.

#define	NOVAS_ARCSEC (NOVAS_ARCMIN / 60.0)
	[rad] An arc second expressed in radians.

#define	NOVAS_C 299792458.0
	[m/s] Speed of light in meters/second is a defining physical constant.

#define	NOVAS_DEGREE (M_PI / 180.0)
	[rad] A degree expressed in radians.

#define	NOVAS_HOURANGLE (M_PI / 12.0)
	[rad] An hour of angle expressed in radians.

#define	NOVAS_KM 1000.0
	[m] A kilometer (km) in meters.

Enumerations
enum	novas_debug_mode { NOVAS_DEBUG_OFF = 0 , NOVAS_DEBUG_ON , NOVAS_DEBUG_EXTRA }
	Settings for 'novas_debug()'. More...

enum	novas_separator_type { NOVAS_SEP_COLONS = 0 , NOVAS_SEP_SPACES , NOVAS_SEP_UNITS , NOVAS_SEP_UNITS_AND_SPACES }
	Separator type to use for broken-down time/angle string representations in HMS/DMS formats. More...

Functions
void	novas_debug (enum novas_debug_mode mode)
	Enables or disables reporting errors and traces to the standard error stream.

double	novas_dms_degrees (const char *restrict dms)
	Returns the decimal degrees for a DMS string specification.

enum novas_debug_mode	novas_get_debug_mode ()
	Returns the current, thread-local, mode for reporting errors encountered (and traces).

double	novas_hms_hours (const char *restrict hms)
	Returns the decimal hours for a HMS string specification.

double	novas_norm_ang (double angle)
	Returns the normalized angle in the [0:2π) range.

double	novas_parse_date (const char restrict date, char *restrict tail)
	Parses an astronomical date/time string into a Julian date specification.

double	novas_parse_date_format (enum novas_calendar_type calendar, enum novas_date_format format, const char restrict date, char *restrict tail)
	Parses a calendar date/time string, expressed in the specified type of calendar, into a Julian day (JD).

double	novas_parse_degrees (const char restrict str, char *restrict tail)
	Parses an angle in degrees from a string that contains either a decimal degrees or else a broken-down DMS representation.

double	novas_parse_dms (const char restrict str, char *restrict tail)
	Parses the decimal degrees for a DMS string specification.

double	novas_parse_hms (const char restrict str, char *restrict tail)
	Parses the decimal hours for a HMS string specification.

double	novas_parse_hours (const char restrict str, char *restrict tail)
	Parses a time or time-like angle from a string that contains either a decimal hours or else a broken-down HMS representation.

double	novas_parse_iso_date (const char restrict date, char *restrict tail)
	Parses an ISO 8601 timestamp, converting it to a Julian day.

enum novas_timescale	novas_parse_timescale (const char restrict str, char *restrict tail)
	Parses the timescale from a string containing a standard abbreviation (case insensitive), and returns the updated parse position after the timescale specification (if any).

int	novas_print_dms (double degrees, enum novas_separator_type sep, int decimals, char *restrict buf, int len)
	Prints an angle in degrees as [-]ddd:mm:ss[.S...] into the specified buffer, with up to nanosecond precision.

int	novas_print_hms (double hours, enum novas_separator_type sep, int decimals, char *restrict buf, int len)
	Prints a time in hours as hh:mm:ss[.S...] into the specified buffer, with up to nanosecond precision.

double	novas_str_degrees (const char *restrict dms)
	Returns an angle parsed from a string that contains either a decimal degrees or else a broken-down DMS representation.

double	novas_str_hours (const char *restrict hms)
	Returns a time or time-like angleparsed from a string that contains either a decimal hours or else a broken-down HMS representation.

int	radec2vector (double ra, double dec, double dist, double *restrict pos)
	Converts equatorial spherical coordinates to a vector (equatorial rectangular coordinates).

int	spin (double angle, const double in, double out)
	Transforms a vector from one coordinate system to another with same origin and axes rotated about the z-axis.

short	vector2radec (const double restrict pos, double restrict ra, double *restrict dec)
	Converts an vector in equatorial rectangular coordinates to equatorial spherical coordinates.

Detailed Description

Macro Definition Documentation

◆ NOVAS_ARCMIN

#define NOVAS_ARCMIN (NOVAS_DEGREE / 60.0)

[rad] An arc minute expressed in radians.

Since: 1.2

◆ NOVAS_ARCSEC

#define NOVAS_ARCSEC (NOVAS_ARCMIN / 60.0)

[rad] An arc second expressed in radians.

Since: 1.2

◆ NOVAS_DEGREE

#define NOVAS_DEGREE (M_PI / 180.0)

[rad] A degree expressed in radians.

Since: 1.2

◆ NOVAS_HOURANGLE

#define NOVAS_HOURANGLE (M_PI / 12.0)

[rad] An hour of angle expressed in radians.

Since: 1.2

◆ NOVAS_KM

#define NOVAS_KM 1000.0

[m] A kilometer (km) in meters.

Since: 1.2

Enumeration Type Documentation

◆ novas_debug_mode

enum novas_debug_mode

Settings for 'novas_debug()'.

See also: novas_debug()

Enumerator
NOVAS_DEBUG_OFF	Do not print errors and traces to the standard error (default).
NOVAS_DEBUG_ON	Print errors and traces to the standard error.
NOVAS_DEBUG_EXTRA	Print all errors and traces to the standard error, even if they may be acceptable behavior.

◆ novas_separator_type

enum novas_separator_type

Separator type to use for broken-down time/angle string representations in HMS/DMS formats.

Since: 1.3

See also: novas_print_hms(), novas_print_dms()

Enumerator
NOVAS_SEP_COLONS	Use colons between components, e.g. '12:34:56'.
NOVAS_SEP_SPACES	Use spaces between components, e.g. '12 34 56'.
NOVAS_SEP_UNITS	Use unit markers after each component, e.g. '12h34m56s'.
NOVAS_SEP_UNITS_AND_SPACES	Useunit markers after each compoent, plus spaces between components, e.g. '12h 34m 56s'.

Function Documentation

◆ novas_debug()

void novas_debug ( enum novas_debug_mode mode )

Enables or disables reporting errors and traces to the standard error stream.

Parameters

mode	NOVAS_DEBUG_OFF (0; or <0), NOVAS_DEBUG_ON (1), or NOVAS_DEBUG_EXTRA (2; or >2).

Since: 1.0

Author: Attila Kovacs

See also: novas_get_debug_mode()

References NOVAS_DEBUG_EXTRA.

◆ novas_dms_degrees()

double novas_dms_degrees ( const char *restrict dms )

Returns the decimal degrees for a DMS string specification.

The degree, (arc)minute, and (arc)second components may be separated by spaces, tabs, colons :, or a combination thereof. Additionally, the degree and minutes may be separated by the letter d, and the minutes and seconds may be separated by m or a single quote ‘’‘. The seconds may be followed by 's’ or double quote ". Finally, the leading or trailing component may additionally be a standalone upper-case letter 'N', 'E', 'S', or 'W' or the words 'North', 'East', 'South', or 'West' (case insensitive), signifying a compass direction.

There is no enforcement on the range of angles that can be represented in this way. Any finite angle is parseable, even if it is outside its conventional range, such as +- 90 degrees N/S.

For example, all of the lines below are valid specifications:

 -179:59:59.999
 -179d 59m 59.999s
 -179 59' 59.999
 179:59:59.999S
 179 59 59.999 W
 179 59 59.999 west
 179_59_59.999__S
 W 179 59 59
 North 179d 59m

At least the leading two components (degrees and arcminutes) are required. If the arcseconds are ommitted, they will be assumed zero, i.e. 179:59 is the same as 179:59:00.000.

NOTES:

To see if the string was fully parsed when returning a valid (non-NAN) value, you can check errno: it should be zero (0) if all non-whitespace characters have been parsed from the input string, or else EINVAL if the parsed value used only the leading part of the string.

Parameters

dms	String specifying degrees, minutes, and seconds, which correspond to an angle. Angles in any range are permitted, but the minutes and seconds must be >=0 and <60.

Returns: [deg] Corresponding decimal angle value, or else NAN if there was an error parsing the string (errno will be set to EINVAL).

Since: 1.3

Author: Attila Kovacs

See also: novas_str_degrees(), novas_parse_dms(), novas_hms_hours()

References novas_parse_dms().

◆ novas_get_debug_mode()

enum novas_debug_mode novas_get_debug_mode ( )

Returns the current, thread-local, mode for reporting errors encountered (and traces).

Returns: The current debug mode in the calling thread.

Since: 1.0

Author: Attila Kovacs

See also: novas_debug()

◆ novas_hms_hours()

double novas_hms_hours ( const char *restrict hms )

Returns the decimal hours for a HMS string specification.

The hour, minute, and second components may be separated by spaces, tabs, colons :, or a combination thereof. Additionally, the hours and minutes may be separated by the letter h, and the minutes and seconds may be separated by m or a single quote ‘’‘. The seconds may be followed by 's’ or double quote ".

There is no enforcement on the range of hours that can be represented in this way. Any finite angle is parseable, even if it is outside its conventional range of 0-24h.

For example, all of the lines below specify the same time:

 23:59:59.999
 23h 59m 59.999s
 23h59'59.999
 23 59 59.999
 23 59
 23h

At least the leading two components (hours and minutes) are required. If the seconds are ommitted, they will be assumed zero, i.e. 23:59 is the same as 23:59:00.000.

NOTES:

To see if the string was fully parsed when returning a valid (non-NAN) value, you can check errno: it should be zero (0) if all non-whitespace characters have been parsed from the input string, or else EINVAL if the parsed value used only the leading part of the string.

Parameters

hms	String specifying hours, minutes, and seconds, which correspond to a time between 0 and 24 h. Time in any range is permitted, but the minutes and seconds must be >=0 and <60.

Returns: [hours] Corresponding decimal time value, or else NAN if there was an error parsing the string (errno will be set to EINVAL).

Since: 1.3

Author: Attila Kovacs

See also: novas_str_hours(), novas_parse_hms(), novas_dms_degrees()

References novas_parse_hms().

◆ novas_norm_ang()

double novas_norm_ang ( double angle )

Returns the normalized angle in the [0:2π) range.

Parameters

angle [rad] an angle in radians.

Returns: [rad] the normalized angle in the [0:2π) range.

Since: 1.0

Author: Attila Kovacs

References TWOPI.

◆ novas_parse_date()

double novas_parse_date	(	const char *restrict	date,
		char **restrict	tail )

Parses an astronomical date/time string into a Julian date specification.

The date must be YMD-type with full year, followed the month (numerical or name or 3-letter abbreviation), and the day. The components may be separated by dash -, underscore _, dot ., slash '/', or spaces/tabs, or any combination thereof. The date may be followed by a time specification in HMS format, separated from the date by the letter T or t, or spaces, comma ,, or semicolon ;, or underscore _ or a combination thereof. Finally, the time may be followed by the letter Z, or z (for UTC) or else {+/-}HH[:[MM]] time zone specification.

For example:

 2025-01-26
 2025 January 26
 2025_Jan_26
 2025-01-26T19:33:08Z
 2025.01.26T19:33:08
 2025 1 26 19h33m28.113
 2025/1/26 19:33:28+02
 2025-01-26T19:33:28-0600
 2025 Jan 26 19:33:28+05:30

are all valid dates that can be parsed.

NOTES:

This function assumes Gregorian dates after their introduction on 1582 October 15, and Julian/Roman dates before that, as was the convention of the time. I.e., the day before of the introduction of the Gregorian calendar reform is 1582 October 4. I.e., you should not use this function with ISO 8601 timestamps containing dates prior to 1582 October 15 (for such date you may use novas_parse_iso_date() instead).
B.C. dates are indicated with years <=0 according to the astronomical and ISO 8601 convention, i.e., X B.C. as (1-X), so 45 B.C. as -44.

Parameters

	date	The astronomical date specification, possibly including time and timezone, in a standard format. The date is assumed to be in the astronomical calendar of date, which differs from ISO 8601 timestamps for dates prior to the Gregorian calendar reform of 1582 October 15 (otherwise, the two are identical).
[out]	tail	(optional) If not NULL it will be set to the next character in the string after the parsed time.

Returns: [day] The Julian Day corresponding to the string date/time specification or NAN if the string is NULL or if it does not specify a date/time in the expected format.

Since: 1.3

Author: Attila Kovacs

See also: novas_parse_iso_date(), novas_parse_date_format(), novas_date(), novas_date_scale(), novas_timescale_for_string(), novas_iso_timestamp(), novas_timestamp()

References NOVAS_ASTRONOMICAL_CALENDAR, novas_parse_date_format(), and NOVAS_YMD.

◆ novas_parse_date_format()

double novas_parse_date_format	(	enum novas_calendar_type	calendar,
		enum novas_date_format	format,
		const char *restrict	date,
		char **restrict	tail )

Parses a calendar date/time string, expressed in the specified type of calendar, into a Julian day (JD).

The date must be composed of a full year (e.g. 2025), a month (numerical or name or 3-letter abbreviation, e.g. "01", "1", "January", or "Jan"), and a day (e.g. "08" or "8"). The components may be separated by dash -, underscore _, dot ., slash '/', or spaces/tabs, or any combination thereof. The components will be parsed in the specified order.

The date may be followed by a time specification in HMS format, separated from the date by the letter T or t, or spaces, comma ,, or semicolon ; or underscore '_', or a combination thereof. Finally, the time may be followed by the letter Z, or z (for UTC) or else by a {+/-}HH[:[MM]] time zone specification.

For example, for format NOVAS_YMD, all of the following strings may specify the date:

 2025-01-26
 2025 January 26
 2025_Jan_26
 2025-01-26T19:33:08Z
 2025.01.26T19:33:08
 2025 1 26 19h33m28.113
 2025/1/26 19:33:28+02
 2025-01-26T19:33:28-0600
 2025 Jan 26 19:33:28+05:30

are all valid dates that can be parsed.

If your date format cannot be parsed with this function, you may parse it with your own function into year, month, day, and decimal hour-of-day components, and use julian_date() with those.

NOTES:

B.C. dates are indicated with years <=0 according to the astronomical and ISO 8601 convention, i.e., X B.C. as (1-X), so 45 B.C. as -44.

Parameters

	calendar	The type of calendar to use: NOVAS_ASTRONOMICAL_CALENDAR, NOVAS_GREGORIAN_CALENDAR, or NOVAS_ROMAN_CALENDAR.
	format	Expected order of date components: NOVAS_YMD, NOVAS_DMY, or NOVAS_MDY.
	date	The date specification, possibly including time and timezone, in the specified standard format.
[out]	tail	(optional) If not NULL it will be set to the next character in the string after the parsed time.

Returns: [day] The Julian Day corresponding to the string date/time specification or NAN if the string is NULL or if it does not specify a date/time in the expected format.

Since: 1.3

Author: Attila Kovacs

See also: novas_parse_date(), novas_parse_iso_date(), novas_timescale_for_string(), novas_iso_timestamp() novas_jd_from_date()

References novas_debug(), NOVAS_DEBUG_OFF, NOVAS_DMY, novas_get_debug_mode(), novas_jd_from_date(), NOVAS_MDY, novas_parse_hms(), and NOVAS_YMD.

◆ novas_parse_degrees()

double novas_parse_degrees	(	const char *restrict	str,
		char **restrict	tail )

Parses an angle in degrees from a string that contains either a decimal degrees or else a broken-down DMS representation.

The decimal representation may be followed by a unit designator: "d", "dg", "deg", "degree", or "degrees", which will be parsed case-insensitively also, if present.

Both DMS and decimal values may start or end with a compass direction: such as an upper-case letter N, E, S, or W, or else the case-insensitive words 'North', 'East', 'South' or 'West'.

There is no enforcement on the range of angles that can be represented in this way. Any finite angle is parseable, even if it is outside its conventional range, such as +- 90 degrees N/S.

A few examples of angles that may be parsed:

 -179:59:59.999
 -179d 59m 59.999s
 179 59' 59.999" S
 179 59 S
 -179.99999d
 -179.99999
 179.99999W
 179.99999 West
 179.99999 deg S
 W 179.99999d
 North 179d 59m
 east 179.99 degrees

Parameters

	str	The input string that specified an angle either as decimal degrees or as a broken down DMS speficication. The decimal value may be followed by the letter `d` immediately. And both the decimal and DMS representation may be ended with a compass direction marker, `N`, `E`, `S`, or `W`. See more in `novas_parse_dms()` on acceptable DMS specifications.
[out]	tail	(optional) If not NULL it will be set to the next character in the string after the parsed angle.

Returns: [deg] The angle represented by the string, or else NAN if the string could not be parsed into an angle value (errno will indicate the type of error).

Since: 1.3

Author: Attila Kovacs

See also: novas_str_degrees(), novas_parse_dms(), novas_parse_hours()

References novas_debug(), NOVAS_DEBUG_OFF, novas_get_debug_mode(), and novas_parse_dms().

◆ novas_parse_dms()

double novas_parse_dms	(	const char *restrict	dms,
		char **restrict	tail )

Parses the decimal degrees for a DMS string specification.

The degree, (arc)minute, and (arc)second components may be separated by spaces, tabs, colons :, underscore _, or a combination thereof. Additionally, the degree and minutes may be separated by the letter d, and the minutes and seconds may be separated by m or a single quote ‘’. The seconds may be followed bysor a double quote"‘. Finally, the leading or trailing component may additionally be a standalone upper-case letter 'N’, 'E', 'S', or 'W' or the words 'North', 'East', 'South', or 'West' (case insensitive), signifying a compass direction.

There is no enforcement on the range of angles that can be represented in this way. Any finite angle is parseable, even if it is outside its conventional range, such as +- 90 degrees N/S.

For example, all of the lines below are valid specifications:

 -179:59:59.999
 -179d 59m 59.999s
 -179 59' 59.999
 179:59:59.999S
 179:59:59.999 W
 179:59:59.999 West
 179_59_59.999__S
 179 59 S
 W 179 59 59
 North 179d 59m

At least the leading two components (degrees and arcminutes) are required. If the arcseconds are ommitted, they will be assumed zero, i.e. 179:59 is the same as 179:59:00.000.

Parameters

	dms	String specifying degrees, minutes, and seconds, which correspond to an angle. Angles in any range are permitted, but the minutes and seconds must be >=0 and <60.
[out]	tail	(optional) If not NULL it will be set to the next character in the string after the parsed time.

Returns: [deg] Corresponding decimal angle value, or else NAN if there was an error parsing the string (errno will be set to EINVAL).

Since: 1.3

Author: Attila Kovacs

See also: novas_dms_degrees(), novas_parse_degrees(), novas_print_dms(), novas_parse_hms()

◆ novas_parse_hms()

double novas_parse_hms	(	const char *restrict	hms,
		char **restrict	tail )

Parses the decimal hours for a HMS string specification.

The hour, minute, and second components may be separated by spaces, tabs, colons :, underscore _, or a combination thereof. Additionally, the hours and minutes may be separated by the letter h, and the minutes and seconds may be separated by m or a single quote ‘’‘. The seconds may be followed by 's’ or double quote ".

There is no enforcement on the range of hours that can be represented in this way. Any finite angle is parseable, even if it is outside its conventional range of 0-24h.

For example, all of the lines below are valid specifications:

 23:59:59.999
 23h 59m 59.999
 23h59'59.999
 23 59 59.999
 23 59

At least the leading two components (hours and minutes) are required. If the seconds are ommitted, they will be assumed zero, i.e. 23:59 is the same as 23:59:00.000.

Parameters

	hms	String specifying hours, minutes, and seconds, which correspond to a time between 0 and 24 h. Time in any range is permitted, but the minutes and seconds must be >=0 and <60.
[out]	tail	(optional) If not NULL it will be set to the next character in the string after the parsed time.

Returns: [hours] Corresponding decimal time value, or else NAN if there was an error parsing the string (errno will be set to EINVAL).

Since: 1.3

Author: Attila Kovacs

See also: novas_hms_hours(), novas_parse_hours(), novas_print_hms(), novas_parse_dms()

◆ novas_parse_hours()

double novas_parse_hours	(	const char *restrict	str,
		char **restrict	tail )

Parses a time or time-like angle from a string that contains either a decimal hours or else a broken-down HMS representation.

The decimal representation may be followed by a unit designator: "h", "hr", "hrs", "hour", or "hours", which will be parsed case-insensitively also, if present.

There is no enforcement on the range of hours that can be represented in this way. Any finite angle is parseable, even if it is outside its conventional range of 0-24h.

A few examples of angles that may be parsed:

 23:59:59.999
 23h 59m 59.999s
 23h59'59.999
 23 59 59.999
 23.999999h
 23.999999 hours
 23.999999

Parameters

	str	The input string that specified an angle either as decimal hours or as a broken down HMS speficication. The decimal value may be immediately followed by a letter 'h'. See more in `novas_parse_hms()` on acceptable HMS input specifications.
[out]	tail	(optional) If not NULL it will be set to the next character in the string after the parsed angle.

Returns: [h] The time-like value represented by the string, or else NAN if the string could not be parsed into a time-like value (errno will indicate the type of error).

Since: 1.3

Author: Attila Kovacs

See also: novas_str_hours(), novas_parse_hms(), novas_parse_degrees()

References novas_debug(), NOVAS_DEBUG_OFF, novas_get_debug_mode(), and novas_parse_hms().

◆ novas_parse_iso_date()

double novas_parse_iso_date	(	const char *restrict	date,
		char **restrict	tail )

Parses an ISO 8601 timestamp, converting it to a Julian day.

It is equivalent to novas_parse_date() for dates after the Gregorian calendar reform of 1582. For earlier dates, ISO timestamps continue to assume the Gregorian calendar (i.e. proleptic Gregorian dates), whereas novas_parse_timestamp() will assume Roman/Julian dates, which were conventionally used before the calendar reform.

NOTES:

B.C. dates are indicated with years <=0 according to the astronomical and ISO 8601 convention, i.e., X B.C. as (1-X), so 45 B.C. as -44.

Parameters

	date	The ISO 8601 date specification, possibly including time and timezone, in a standard format.
[out]	tail	(optional) If not NULL it will be set to the next character in the string after the parsed time.

Returns: [day] The Julian Day corresponding to the string date/time specification or NAN if the string is NULL or if it does not specify a date/time in the expected format.

Since: 1.3

Author: Attila Kovacs

See also: novas_iso_timestamp(), novas_parse_date()

References NOVAS_GREGORIAN_CALENDAR, novas_parse_date_format(), and NOVAS_YMD.

◆ novas_parse_timescale()

enum novas_timescale novas_parse_timescale	(	const char *restrict	str,
		char **restrict	tail )

Parses the timescale from a string containing a standard abbreviation (case insensitive), and returns the updated parse position after the timescale specification (if any).

The following timescale values are recognised: "UTC", "UT", "UT0", "UT1", "GMT", "TAI", "GPS", "TT", "ET", "TCG", "TCB", "TDB".

Parameters

	str	String specifying an astronomical timescale. Leading white spaces will be skipped over.
[out]	tail	(optional) If not NULL it will be set to the next character in the string after the parsed timescale specification.

Returns: The SuperNOVAS timescale constant (<=0), or else -1 if the string was NULL, empty, or could not be matched to a timescale value (errno will be set to EINVAL also).

Since: 1.3

Author: Attila Kovacs

See also: novas_timescale_for_string(), novas_set_str_time(), novas_print_timescale()

References novas_timescale_for_string(), and NOVAS_UTC.

◆ novas_print_dms()

int novas_print_dms	(	double	degrees,
		enum novas_separator_type	sep,
		int	decimals,
		char *restrict	buf,
		int	len )

Prints an angle in degrees as [-]ddd:mm:ss[.S...] into the specified buffer, with up to nanosecond precision.

The degrees component is always printed as 4 characters (up to 3 digits plus optional negative sign), so the output is always aligned. If positive values are expected to be explicitly signed also, the caller may simply put the '+' sign into the leading byte.

NaN and infinite values, are printed as their standard floating-point representations.

Parameters

	degrees	[deg] angle value
	sep	Type of separators to use between or after components. If the separator value is outside of the enum range, it will default to using colons.
	decimals	Requested number of decimal places to print for the seconds [0:9].
[out]	buf	String buffer in which to print DMS string, represented in the [-180:180) degree range.
	len	Maximum number of bytes that may be written into the output buffer, including termination.

Returns: The number of characters actually printed in the buffer, excluding termination, or else -1 if the input buffer is NULL or the length is less than 1 (errno will be set to EINVAL).

Since: 1.3

Author: Attila Kovacs

See also: novas_parse_dms(), novas_print_hms()

References NOVAS_SEP_COLONS, NOVAS_SEP_SPACES, NOVAS_SEP_UNITS, and NOVAS_SEP_UNITS_AND_SPACES.

◆ novas_print_hms()

int novas_print_hms	(	double	hours,
		enum novas_separator_type	sep,
		int	decimals,
		char *restrict	buf,
		int	len )

Prints a time in hours as hh:mm:ss[.S...] into the specified buffer, with up to nanosecond precision.

NaN and infinite values, are printed as their standard floating-point representations.

Parameters

	hours	[h] time value
	sep	Type of separators to use between or after components. If the separator value is outside of the enum range, it will default to using colons.
	decimals	Requested number of decimal places to print for the seconds [0:9].
[out]	buf	String buffer in which to print HMS string, represented in the [0:24) hour range.
	len	Maximum number of bytes that may be written into the output buffer, including termination.

Returns: The number of characters actually printed in the buffer, excluding termination, or else -1 if the input buffer is NULL or the length is less than 1 (errno will be set to EINVAL).

Since: 1.3

Author: Attila Kovacs

See also: novas_parse_hms(), novas_print_dms(), novas_timestamp()

References NOVAS_SEP_COLONS, NOVAS_SEP_SPACES, NOVAS_SEP_UNITS, and NOVAS_SEP_UNITS_AND_SPACES.

◆ novas_str_degrees()

double novas_str_degrees ( const char *restrict str )

Returns an angle parsed from a string that contains either a decimal degrees or else a broken-down DMS representation.

See novas_parse_degrees() to see what string representations may be used.

To see if the string was fully parsed when returning a valid (non-NAN) value, you can check errno: it should be zero (0) if all non-whitespace and punctuation characters have been parsed from the input string, or else EINVAL if the parsed value used only the leading part of the string.

Parameters

str	The input string that specified an angle either as decimal degrees or as a broken down DMS speficication. The decimal value may be immediately followed by a letter 'd'. See more in `novas_parse_degrees()` on acceptable input specifications.

Returns: [deg] The angle represented by the string, or else NAN if the string could not be parsed into an angle value (errno will indicate the type of error).

Since: 1.3

Author: Attila Kovacs

See also: novas_parse_degrees(), novas_parse_dms(), novas_print_dms(), novas_str_hours()

References novas_parse_degrees().

◆ novas_str_hours()

double novas_str_hours ( const char *restrict str )

Returns a time or time-like angleparsed from a string that contains either a decimal hours or else a broken-down HMS representation.

See novas_parse_hours() to see what string representations may be used.

To check if the string was fully parsed when returning a valid (non-NAN) value you can check errno: it should be zero (0) if all non-whitespace and punctuation characters have been parsed from the input string, or else EINVAL if the parsed value used only the leading part of the string.

Parameters

str	The input string that specified an angle either as decimal hours or as a broken down HMS speficication. The decimal value may be immediately followed by a letter 'h'. See more in `novas_parse_hours()` on acceptable input specifications.

Returns: [h] The time-like value represented by the string, or else NAN if the string could not be parsed into a time-like value (errno will indicate the type of error).

Since: 1.3

Author: Attila Kovacs

See also: novas_parse_hours(), novas_parse_hms(), novas_print_hms(), novas_str_degrees()

References novas_parse_hours().

◆ radec2vector()

int radec2vector	(	double	ra,
		double	dec,
		double	dist,
		double *restrict	pos )

Converts equatorial spherical coordinates to a vector (equatorial rectangular coordinates).

Parameters

	ra	[h] Right ascension (hours).
	dec	[deg] Declination (degrees).
	dist	[AU] Distance (AU)
[out]	pos	[AU] Position 3-vector, equatorial rectangular coordinates (AU).

Returns: 0 if successful, or -1 if the vector argument is NULL.

See also: vector2radec(), starvectors()

◆ spin()

int spin	(	double	angle,
		const double *	in,
		double *	out )

Transforms a vector from one coordinate system to another with same origin and axes rotated about the z-axis.

REFERENCES:

Kaplan, G. H. et. al. (1989). Astron. Journ. 97, 1197-1210.

Parameters

	angle	[deg] Angle of coordinate system rotation, positive counterclockwise when viewed from +z, in degrees.
	in	Input position vector.
[out]	out	Position vector expressed in new coordinate system rotated about z by 'angle'. It can be the same vector as the input.

Returns: 0 if successful, or -1 if the output vector is NULL.

References TWOPI.

◆ vector2radec()

short vector2radec	(	const double *restrict	pos,
		double *restrict	ra,
		double *restrict	dec )

Converts an vector in equatorial rectangular coordinates to equatorial spherical coordinates.

REFERENCES:

Kaplan, G. H. et. al. (1989). Astron. Journ. 97, 1197-1210.

Parameters

	pos	Position 3-vector, equatorial rectangular coordinates.
[out]	ra	[h] Right ascension in hours [0:24] or NAN if the position vector is NULL or a null-vector. It may be NULL if notrequired.
[out]	dec	[deg] Declination in degrees [-90:90] or NAN if the position vector is NULL or a null-vector. It may be NULL if not required.

Returns: 0 if successful, -1 of any of the arguments are NULL, or 1 if all input components are 0 so 'ra' and 'dec' are indeterminate, or else 2 if both x and y are zero, but z is nonzero, and so 'ra' is indeterminate.

See also: radec2vector()

Macros

Enumerations

Functions

Detailed Description

Macro Definition Documentation

◆ NOVAS_ARCMIN

◆ NOVAS_ARCSEC

◆ NOVAS_DEGREE

◆ NOVAS_HOURANGLE

◆ NOVAS_KM

Enumeration Type Documentation

◆ novas_debug_mode

◆ novas_separator_type

Function Documentation

◆ novas_debug()

◆ novas_dms_degrees()

◆ novas_get_debug_mode()

◆ novas_hms_hours()

◆ novas_norm_ang()

◆ novas_parse_date()

◆ novas_parse_date_format()

◆ novas_parse_degrees()

◆ novas_parse_dms()

◆ novas_parse_hms()

◆ novas_parse_hours()

◆ novas_parse_iso_date()

◆ novas_parse_timescale()

◆ novas_print_dms()

◆ novas_print_hms()

◆ novas_str_degrees()

◆ novas_str_hours()

◆ radec2vector()

◆ spin()

◆ vector2radec()