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Add the Yereim's bain hashmashos
13.5, 16.875 and 18 minute variants, along with computed degree based offsets.
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‎src/main/java/com/kosherjava/zmanim/ComplexZmanimCalendar.java‎

Lines changed: 155 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -375,6 +375,36 @@ public class ComplexZmanimCalendar extends ZmanimCalendar {
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* @see #getTzaisGeonim9Point75Degrees()
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*/
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protected static final double ZENITH_9_POINT_75 = GEOMETRIC_ZENITH + 9.75;
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/**
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* The zenith of 2.03° above {@link #GEOMETRIC_ZENITH geometric zenith} (90°). This calculation is used for
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* calculating the start of <em>bain hashmashos</em> (twilight) of 13.5 minutes before sunset converted to degrees
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* according to the Yereim. As is traditional with degrees below the horizon, this is calculated without refraction
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* and from the center of the sun. It would be 0.833&deg; less without this.
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*
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* @see #getBainHasmashosYereim2Point03Degrees()
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*/
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protected static final double ZENITH_MINUS_2_POINT_03 = GEOMETRIC_ZENITH - 2.03;
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/**
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* The zenith of 2.75&deg; above {@link #GEOMETRIC_ZENITH geometric zenith} (90&deg;). This calculation is used for
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* calculating the start of <em>bain hashmashos</em> (twilight) of 16.875 minutes before sunset converted to degrees
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* according to the Yereim. As is traditional with degrees below the horizon, this is calculated without refraction
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* and from the center of the sun. It would be 0.833&deg; less without this.
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*
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* @see #getBainHasmashosYereim2Point75Degrees()
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*/
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protected static final double ZENITH_MINUS_2_POINT_75 = GEOMETRIC_ZENITH - 2.75;
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/**
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* The zenith of 2.99&deg; above {@link #GEOMETRIC_ZENITH geometric zenith} (90&deg;). This calculation is used for
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* calculating the start of <em>bain hashmashos</em> (twilight) of 18 minutes before sunset converted to degrees
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* according to the Yereim. As is traditional with degrees below the horizon, this is calculated without refraction
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* and from the center of the sun. It would be 0.833&deg; less without this.
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*
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* @see #getBainHasmashosYereim2Point99Degrees()
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*/
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protected static final double ZENITH_MINUS_2_POINT_99 = GEOMETRIC_ZENITH - 2.99;
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/**
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* The offset in minutes (defaults to 40) after sunset used for <em>tzeit</em> for Ateret Torah calculations.
@@ -1912,13 +1942,13 @@ public Date getPlagAlos16Point1ToTzaisGeonim7Point083Degrees() {
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}
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/**
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* Method to return <em>Bain Hashmashos</em> of <em>Rabbeinu Tam</em> calculated when the sun is
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* Method to return the beginning of <em>bain hashmashos</em> of <em>Rabbeinu Tam</em> calculated when the sun is
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* {@link #ZENITH_13_POINT_24 13.24&deg;} below the western {@link #GEOMETRIC_ZENITH geometric horizon} (90&deg;)
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* after sunset. This calculation is based on the same calculation of {@link #getBainHasmashosRT58Point5Minutes()
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* Bain Hashmashos Rabbeinu Tam 58.5 minutes} but uses a degree based calculation instead of 58.5 exact minutes. This
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* calculation is based on the position of the sun 58.5 minutes after sunset in Jerusalem during the equinox (on
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* March 16, about 4 days before the astronomical equinox, the day that a solar hour is 60 minutes) which calculates
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* to 13.24&deg; below {@link #GEOMETRIC_ZENITH geometric zenith}.
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* <em>bain hashmashos</em> Rabbeinu Tam 58.5 minutes} but uses a degree based calculation instead of 58.5 exact
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* minutes. This calculation is based on the position of the sun 58.5 minutes after sunset in Jerusalem during the
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* equinox (on March 16, about 4 days before the astronomical equinox, the day that a solar hour is 60 minutes)
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* which calculates to 13.24&deg; below {@link #GEOMETRIC_ZENITH geometric zenith}.
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* NOTE: As per Yisrael Vehazmanim Vol. III page 1028 No 50, a dip of slightly less than 13&deg; should be used.
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* Calculations show that the proper dip to be 13.2456&deg; (truncated to 13.24 that provides about 1.5 second
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* earlier (<em>lechumra</em>) time) below the horizon at that time. This makes a difference of 1 minute and 10
@@ -1939,9 +1969,9 @@ public Date getBainHasmashosRT13Point24Degrees() {
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}
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/**
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* This method returns <em>Bain Hashmashos</em> of <em>Rabbeinu Tam</em> calculated as a 58.5 minute offset after
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* sunset. <em>Bain hashmashos</em> is 3/4 of a <em>Mil</em> before <em>tzais</em> or 3 1/4 <em>Mil</em> after
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* sunset. With a <em>Mil</em> calculated as 18 minutes, 3.25 * 18 = 58.5 minutes.
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* This method returns the beginning of <em>Bain hashmashos</em> of <em>Rabbeinu Tam</em> calculated as a 58.5
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* minute offset after sunset. <em>bain hashmashos</em> is 3/4 of a <em>Mil</em> before <em>tzais</em> or 3 1/4
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* <em>Mil</em> after sunset. With a <em>Mil</em> calculated as 18 minutes, 3.25 * 18 = 58.5 minutes.
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*
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* @return the <code>Date</code> of 58.5 minutes after sunset. If the calculation can't be computed such as in the
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* Arctic Circle where there is at least one day a year where the sun does not rise, and one where it does
@@ -1954,8 +1984,8 @@ public Date getBainHasmashosRT58Point5Minutes() {
19541984
}
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/**
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* This method returns the time of <em>bain hashmashos</em> based on the calculation of 13.5 minutes (3/4 of an 18
1958-
* minute <em>Mil</em> before shkiah calculated as {@link #getTzaisGeonim7Point083Degrees() 7.083&deg;}.
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* This method returns the beginning of <em>bain hashmashos</em> based on the calculation of 13.5 minutes (3/4 of an
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* 18 minute <em>Mil</em>) before <em>shkiah</em> calculated as {@link #getTzaisGeonim7Point083Degrees() 7.083&deg;}.
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*
19601990
* @return the <code>Date</code> of the <em>bain hashmashos</em> of <em>Rabbeinu Tam</em> in this calculation. If the
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* calculation can't be computed such as northern and southern locations even south of the Arctic Circle and
@@ -1969,10 +1999,10 @@ public Date getBainHasmashosRT13Point5MinutesBefore7Point083Degrees() {
19691999
}
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19712001
/**
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* This method returns <em>bain hashmashos</em> of <em>Rabbeinu Tam</em> calculated according to the opinion of the
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* <em>Divrei Yosef</em> (see Yisrael Vehazmanim) calculated 5/18th (27.77%) of the time between <em>alos</em>
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* (calculated as 19.8&deg; before sunrise) and sunrise. This is added to sunset to arrive at the time for
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* <em>bain hashmashos</em> of <em>Rabbeinu Tam</em>).
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* This method returns the beginning of <em>bain hashmashos</em> of <em>Rabbeinu Tam</em> calculated according to the
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* opinion of the <em>Divrei Yosef</em> (see Yisrael Vehazmanim) calculated 5/18th (27.77%) of the time between
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* <em>alos</em> (calculated as 19.8&deg; before sunrise) and sunrise. This is added to sunset to arrive at the time
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* for <em>bain hashmashos</em> of <em>Rabbeinu Tam</em>).
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*
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* @return the <code>Date</code> of <em>bain hashmashos</em> of <em>Rabbeinu Tam</em> for this calculation. If the
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* calculation can't be computed such as northern and southern locations even south of the Arctic Circle and
@@ -1989,7 +2019,117 @@ public Date getBainHasmashosRT2Stars() {
19892019

19902020
return getTimeOffset(getElevationAdjustedSunset(), (sunrise.getTime() - alos19Point8.getTime()) * (5 / 18d));
19912021
}
1992-
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/**
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* This method returns the beginning of <em>bain hashmashos</em> (twilight) according to the <a href=
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* "https://en.wikipedia.org/wiki/Eliezer_ben_Samuel">Yereim (Rabbi Eliezer of Metz)</a> calculated as 18 minutes
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* or 3/4 of a 24 minute <em>Mil</em> before sunset. According to the Yereim, <em>bain hashmashos</em> starts 3/4
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* of a <em>Mil</em> before sunset and <em>tzais</em> or nightfall starts at sunset.
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*
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* @return the <code>Date</code> of 18 minutes before sunset. If the calculation can't be computed such as in the
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* Arctic Circle where there is at least one day a year where the sun does not rise, and one where it does
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* not set, a null will be returned. See detailed explanation on top of the {@link AstronomicalCalendar}
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* documentation.
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* @see #getBainHasmashosYereim2Point99Degrees()
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*/
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public Date getBainHasmashosYereim18Minutes() {
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return getTimeOffset(getElevationAdjustedSunset(), -18 * MINUTE_MILLIS);
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}
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/**
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* This method returns the beginning of <em>hain hashmashos</em> (twilight) according to the <a href=
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* "https://en.wikipedia.org/wiki/Eliezer_ben_Samuel">Yereim (Rabbi Eliezer of Metz)</a> calculated as the sun's
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* position 2.99&deg; above the horizon during the equinox (on March 16, about 4 days before the astronomical
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* equinox, the day that a solar hour is 60 minutes) in Yerushalayim, its position 18 minutes or 3/4 of an 24
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* minute <em>Mil</em> before sunset. According to the Yereim, bain hashmashos starts 3/4 of a <em>Mil</em> before
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* sunset and <em>tzais</em> or nightfall starts at sunset.
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*
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* @return the <code>Date</code> of the sun's position 2.99&deg; minutes before sunset. If the calculation can't
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* be computed such as in the Arctic Circle where there is at least one day a year where the sun does not
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* rise, and one where it does not set, a null will be returned. See detailed explanation on top of the
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* {@link AstronomicalCalendar} documentation.
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*
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* @see #ZENITH_MINUS_2_POINT_99
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* @see #getBainHasmashosYereim18Minutes()
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*/
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public Date getBainHasmashosYereim2Point99Degrees() {
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return getSunsetOffsetByDegrees(ZENITH_MINUS_2_POINT_99);
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}
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/**
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* This method returns the beginning of <em>bain hashmashos</em> (twilight) according to the <a href=
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* "https://en.wikipedia.org/wiki/Eliezer_ben_Samuel">Yereim (Rabbi Eliezer of Metz)</a> calculated as 16.875
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* minutes or 3/4 of a 22.5 minute <em>Mil</em> before sunset. According to the Yereim, bain hashmashos starts 3/4 of a
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* <em>Mil</em> before sunset and <em>tzais</em> or nightfall starts at sunset.
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*
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* @return the <code>Date</code> of 16.875 minutes before sunset. If the calculation can't be computed such as in the
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* Arctic Circle where there is at least one day a year where the sun does not rise, and one where it does
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* not set, a null will be returned. See detailed explanation on top of the {@link AstronomicalCalendar}
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* documentation.
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*
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* @see #getBainHasmashosYereim2Point75Degrees()
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*/
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public Date getBainHasmashosYereim16Point875Minutes() {
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return getTimeOffset(getElevationAdjustedSunset(), -16.875 * MINUTE_MILLIS);
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}
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/**
2077+
* This method returns the beginning of <em>bain hashmashos</em> (twilight) according to the <a href=
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* "https://en.wikipedia.org/wiki/Eliezer_ben_Samuel">Yereim (Rabbi Eliezer of Metz)</a> calculated as the sun's
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* position 2.75&deg; above the horizon during the equinox (on March 16, about 4 days before the astronomical
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* equinox, the day that a solar hour is 60 minutes) in Yerushalayim, its position 16.875 minutes or 3/4 of an 18
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* minute <em>Mil</em> before sunset. According to the Yereim, bain hashmashos starts 3/4 of a <em>Mil</em> before
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* sunset and <em>tzais</em> or nightfall starts at sunset.
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*
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* @return the <code>Date</code> of the sun's position 2.75&deg; minutes before sunset. If the calculation can't
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* be computed such as in the Arctic Circle where there is at least one day a year where the sun does not
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* rise, and one where it does not set, a null will be returned. See detailed explanation on top of the
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* {@link AstronomicalCalendar} documentation.
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*
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* @see #ZENITH_MINUS_2_POINT_75
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* @see #getBainHasmashosYereim16Point875Minutes()
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*/
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public Date getBainHasmashosYereim2Point75Degrees() {
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return getSunsetOffsetByDegrees(ZENITH_MINUS_2_POINT_75);
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}
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/**
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* This method returns the beginning of <em>bain hashmashos</em> (twilight) according to the <a href=
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* "https://en.wikipedia.org/wiki/Eliezer_ben_Samuel">Yereim (Rabbi Eliezer of Metz)</a> calculated as 13.5 minutes
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* or 3/4 of an 18 minute <em>Mil</em> before sunset. According to the Yereim, bain hashmashos starts 3/4 of a
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* <em>Mil</em> before sunset and <em>tzais</em> or nightfall starts at sunset.
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*
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* @return the <code>Date</code> of 13.5 minutes before sunset. If the calculation can't be computed such as in the
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* Arctic Circle where there is at least one day a year where the sun does not rise, and one where it does
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* not set, a null will be returned. See detailed explanation on top of the {@link AstronomicalCalendar}
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* documentation.
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*
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* @see #getBainHasmashosYereim2Point03Degrees()
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*/
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public Date getBainHasmashosYereim13Point5Minutes() {
2110+
return getTimeOffset(getElevationAdjustedSunset(), -13.5 * MINUTE_MILLIS);
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}
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/**
2114+
* This method returns the beginning of <em>bain hashmashos</em> according to the <a href=
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* "https://en.wikipedia.org/wiki/Eliezer_ben_Samuel">Yereim (Rabbi Eliezer of Metz)</a> calculated as the sun's
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* position 2.03&deg; above the horizon during the equinox (on March 16, about 4 days before the astronomical
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* equinox, the day that a solar hour is 60 minutes) in Yerushalayim, its position 13.5 minutes or 3/4 of an 18
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* minute <em>Mil</em> before sunset. According to the Yereim, bain hashmashos starts 3/4 of a <em>Mil</em> before
2119+
* sunset and <em>tzais</em> or nightfall starts at sunset.
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*
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* @return the <code>Date</code> of the sun's position 2.03&deg; minutes before sunset. If the calculation can't
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* be computed such as in the Arctic Circle where there is at least one day a year where the sun does not
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* rise, and one where it does not set, a null will be returned. See detailed explanation on top of the
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* {@link AstronomicalCalendar} documentation.
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*
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* @see #ZENITH_MINUS_2_POINT_03
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* @see #getBainHasmashosYereim13Point5Minutes()
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*/
2129+
public Date getBainHasmashosYereim2Point03Degrees() {
2130+
return getSunsetOffsetByDegrees(ZENITH_MINUS_2_POINT_03);
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}
2132+
19932133
/**
19942134
* This method returns the <em>tzais</em> (nightfall) based on the opinion of the <em>Geonim</em> calculated at the
19952135
* sun's position at {@link #ZENITH_3_POINT_7 3.7&deg;} below the western horizon.

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