Struct JulianDate 

pub struct JulianDate { /* private fields */ }

Julian date representation for astronomical calculations.

Follows the SPA algorithm described in Reda & Andreas (2003). Supports both Julian Date (JD) and Julian Ephemeris Date (JDE) calculations.

Implementations

impl JulianDate

pub fn from_datetime<Tz: TimeZone>( datetime: &DateTime<Tz>, delta_t: f64, ) -> Result<Self>

Creates a new Julian date from a timezone-aware chrono DateTime.

This function properly handles timezone-aware datetimes by converting the entire datetime to UTC for accurate Julian Date calculations. Solar calculations require proper handling of the Earth’s rotation relative to the Sun, which is referenced to Universal Time.

Arguments

• datetime - Timezone-aware date and time
• delta_t - ΔT in seconds (difference between TT and UT1)

Returns

Julian date or error if the date is invalid

Errors

Returns error if the date/time components are invalid (e.g., invalid month, day, hour).

pub fn from_utc( year: i32, month: u32, day: u32, hour: u32, minute: u32, second: f64, delta_t: f64, ) -> Result<Self>

Creates a new Julian date from year, month, day, hour, minute, and second in UTC.

Arguments

• year - Year (can be negative for BCE years)
• month - Month (1-12)
• day - Day of month (1-31)
• hour - Hour (0-23)
• minute - Minute (0-59)
• second - Second (0-59, can include fractional seconds)
• delta_t - ΔT in seconds (difference between TT and UT1)

Returns

Julian date or error if the date is invalid

Errors

Returns error if any date/time component is outside valid ranges (month 1-12, day 1-31, hour 0-23, minute 0-59, second 0-59.999).

Example

let jd = JulianDate::from_utc(2023, 6, 21, 12, 0, 0.0, 69.0).unwrap();
assert!(jd.julian_date() > 2_460_000.0);

pub fn from_utc_simple( year: i32, month: u32, day: u32, hour: u32, minute: u32, second: f64, ) -> Result<Self>

Creates a Julian date assuming ΔT = 0.

Arguments

• year, month, day, hour, minute, second - UTC date/time components

Returns

Julian date with ΔT = 0

Errors

Returns error if the date/time components are outside valid ranges.

pub const fn julian_date(&self) -> f64

Gets the Julian Date (JD) value.

Returns

Julian Date referenced to UT1

pub const fn delta_t(&self) -> f64

Gets the ΔT value in seconds.

Returns

ΔT (Delta T) in seconds

pub fn julian_ephemeris_day(&self) -> f64

Calculates the Julian Ephemeris Day (JDE).

JDE = JD + ΔT/86400

Returns

Julian Ephemeris Day

pub fn julian_century(&self) -> f64

Calculates the Julian Century (JC) from J2000.0.

JC = (JD - 2451545.0) / 36525

Returns

Julian centuries since J2000.0 epoch

pub fn julian_ephemeris_century(&self) -> f64

Calculates the Julian Ephemeris Century (JCE) from J2000.0.

JCE = (JDE - 2451545.0) / 36525

Returns

Julian ephemeris centuries since J2000.0 epoch

pub fn julian_ephemeris_millennium(&self) -> f64

Calculates the Julian Ephemeris Millennium (JME) from J2000.0.

JME = JCE / 10

Returns

Julian ephemeris millennia since J2000.0 epoch

Trait Implementations

impl Clone for JulianDate

fn clone(&self) -> JulianDate

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for JulianDate

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for JulianDate

fn eq(&self, other: &JulianDate) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for JulianDate

impl StructuralPartialEq for JulianDate