Struct Period

Source

pub struct Period(/* private fields */);

Expand description

Angles and Time are the most prominent use for this type

Property	To Method	From Method
Degrees (Decimal)	`Period::degrees()`	`Period::from_degrees()`
Radians	`Period::radians()`	`Period::from_radians()`
Turns ([0,1])	`Period::turns()`	`Period::from_turns()`
Hours (Decimal)	`Period::decimal()`	`Period::from_decimal()`
Clock Time	`Period::clock()`	`Period::from_clock()`
Degrees (DMS)	`Period::degminsec()`	`Period::from_degminsec()`
Sine	`Period::sin()`	`Period::asin()`
Cosine	`Period::cos()`	`Period::acos()`
Tangent	`Period::tan()`	`Period::atan2()`

Additional Methods:

Latitude displaying: Period::to_latitude()
GST Correction: Period::gst() and Period::ungst()
Inverse of angle: Period::inverse()

Implementations§

Source §

impl Period

Source

pub const fn radians(self) -> f64

Returns the angle as radians.

This is the only function that should directly access the fields of the type.

use pracstro::time::Period;
Period::from_degrees(180.0).radians(); // Pi

Source

pub const fn from_radians(x: f64) -> Self

Constructs a angle from radians, reducing it to the range of [0, 2*PI].

This is the one of the two only functions that directly access Period. Reduction to the desired range is done with Least Positive Residue instead of the remainder operator.

use pracstro::time::Period;
Period::from_radians(std::f64::consts::PI).degrees(); // 180.0

Source

pub const fn to_latitude(self) -> Self

Converts angles internally so that formatting them as latitudes makes sense

This should be used directly in conjunction with a formatting function. The main use case for this is in coordinate handling where angles of latitude can be negative. This is the only other function that should be able to directly access Period than Period::from_radians().

use pracstro::time::Period;
Period::from_degrees(-25.0).degrees(); // 335.0
Period::from_degrees(-25.0).to_latitude().degrees(); // -25.0

Examples found in repository ?

examples/speed.rs (line 23)

19    fn ephem() {
20        let now = time::Date::now();
21        for p in sol::PLANETS {
22            let (ra, de) = p.location(now).equatorial();
23            (ra.clock(), de.to_latitude().degminsec());
24        }
25    }

More examples

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examples/ephem.rs (line 7)

3fn main() {
4    let now = time::Date::now();
5    for p in sol::PLANETS {
6        let (ra, de) = p.location(now).equatorial();
7        let ((rah, ram, _), (ded, dem, _)) = (ra.clock(), de.to_latitude().degminsec());
8        println!(
9            "{:<10} {:>2}h{:02} RA {:>3}°{:02}' De {:.2} AU",
10            p.name,
11            rah,
12            ram,
13            ded,
14            dem,
15            p.distance(now)
16        );
17    }
18}

Source

pub const fn degrees(self) -> f64

Returns the angle as fractional degrees.

A wrapper around f64::to_degrees()

use pracstro::time::Period;
Period::from_degrees(-25.0).degrees(); // 335.0

Source

pub const fn from_degrees(x: f64) -> Self

Constructs an angle from fractional degrees.

A wrapper around f64::to_radians()

use pracstro::time::Period;
Period::from_degrees(-25.0).degrees(); // 335.0

Source

pub const fn turns(self) -> f64

Returns the angle in the range between 0 and 1 (i.e. turns)

Used in the calculation for the illuminated fraction of planets

Source

pub const fn from_turns(x: f64) -> Self

Constructs an angle from a value between 0 and 1

Used in the calculation for the illuminated fraction of planets

Source

pub const fn decimal(self) -> f64

Returns the angle in fractional number of hours

A wrapper around Period::degrees() and one division by 15. Since one hour is 15 degrees of rotation

use pracstro::time::Period;
Period::from_degrees(120.0).decimal(); // 8.0

Source

pub const fn from_decimal(x: f64) -> Self

Constructs an angle from a fractional number of hours

A wrapper around Period::from_degrees() and one multiplication by 15. Since one hour is 15 degrees of rotation

use pracstro::time::Period;
Period::from_decimal(8.0).degrees(); // 120.00

Source

pub fn clock(self) -> (u8, u8, f64)

Returns (Hour, Minute, Second) of a time/angle

Used in hour-angle displays for some coordinate systems, and in times.

use pracstro::time::Period;
Period::from_decimal(8.0).clock(); // (8, 0, 0.0)

Examples found in repository ?

examples/speed.rs (line 23)

19    fn ephem() {
20        let now = time::Date::now();
21        for p in sol::PLANETS {
22            let (ra, de) = p.location(now).equatorial();
23            (ra.clock(), de.to_latitude().degminsec());
24        }
25    }

More examples

Hide additional examples

examples/ephem.rs (line 7)

3fn main() {
4    let now = time::Date::now();
5    for p in sol::PLANETS {
6        let (ra, de) = p.location(now).equatorial();
7        let ((rah, ram, _), (ded, dem, _)) = (ra.clock(), de.to_latitude().degminsec());
8        println!(
9            "{:<10} {:>2}h{:02} RA {:>3}°{:02}' De {:.2} AU",
10            p.name,
11            rah,
12            ram,
13            ded,
14            dem,
15            p.distance(now)
16        );
17    }
18}

Source

pub fn from_clock(h: u8, m: u8, s: f64) -> Self

Constructs an angle out of an hour, minute, and second

Used in hour-angle displays for some coordinate systems, and in times.

use pracstro::time::Period;
Period::from_clock(8, 0, 0.0).decimal(); // 8.0

Source

pub fn degminsec(self) -> (i16, u8, f64)

Converts an angle to a degree with arcminutes and arcseconds

Examples found in repository ?

examples/speed.rs (line 23)

19    fn ephem() {
20        let now = time::Date::now();
21        for p in sol::PLANETS {
22            let (ra, de) = p.location(now).equatorial();
23            (ra.clock(), de.to_latitude().degminsec());
24        }
25    }

More examples

Hide additional examples

examples/ephem.rs (line 7)

3fn main() {
4    let now = time::Date::now();
5    for p in sol::PLANETS {
6        let (ra, de) = p.location(now).equatorial();
7        let ((rah, ram, _), (ded, dem, _)) = (ra.clock(), de.to_latitude().degminsec());
8        println!(
9            "{:<10} {:>2}h{:02} RA {:>3}°{:02}' De {:.2} AU",
10            p.name,
11            rah,
12            ram,
13            ded,
14            dem,
15            p.distance(now)
16        );
17    }
18}