Molad

A Hebrew calendar application for a Java ^TM mobile device

Version  1.1

Iyar 5765 (May 2005)

Content

• Molad and 'Molad'
• Credits and Links
• Releases
• New to version 1.1 (14 Iyar 5765 / 23 May 2005)
• From the original release
• Support
• For developers

• Hebrew calendar
• Julian and Gregorian Calendars
• Representing Hebrew numerals in native format.

• Terms Explained
• Phone Keys
• Other Keys
• Commands
• Date View ("calendar") Screen
• Date View Data
• Controlling Date View Screen
• Date View Commands
• Multiple Pages and Auto-Turn Page
• Date Set Screen
• Controlling Date Set Screen
• Date Set Commands
• Using a pointer device (stylus)
• Settings Screen
• Holidays and Custom Events
• Event Display Options
• Customising Holidays
• Custom Events
• Adar Bet Events

Introduction

Molad and 'Molad'

This application is designed to suit any Java ^TM compatible mobile device with 50K of RAM. Colour support and screen size 120x120 or more (e.g. Nokia Series 40 and 60,  Motorola T720, A830 etc) would be an advantage. With Siemens mobile devices (screen size 101x64 or 101x80 pixels), or Nokia Series 30 (96x65 pixels) the application feels less comfortable though is still fully operational.

The following features are supported:

• Calendar page for a specified day
• List of coming and past events
• Omer days
• Sedrot (Torah readings)
• Custom events

Because of limited resources the application cannot be as versatile as the ones designed for a PC, or for a specific mobile device. Here are the features that I would like to support, but either would make the application less efficient or too big, or simply impossible to implement:

• Calendar clock - I might find time for that one day.
• Monthly calendar pages - this would look terribly bad on a small screen.
• Sunrise, sunset, candle lighting time. Probably all applications (whether or not they tell it) use a sunrise/sunset algorithm from Almamac of Computers 1990, published by Nautical Almanac Office United States Naval Observatory Washington, DC 20392. The algorithm significantly relies a lot of trigonometric functions, while J2ME doesn't provide event basic ones. Writing own classes would be inefficient, because of a lot of floating-point calculation being involved. Floating-point calculation can be avoided with precalculated tables, but that would either be inaccurate, or enormously increase the size of application.
• Introduction date for each holiday. As far as I know, holidays like Chanukah or Purim are not as old as Pesach, therefore it doesn't look logical to show Chanukah say for year 1000 H.C. Unfortunately, I don't know exact introduction dates even for new holidays like Yom Zikaron, or Yom Atzmaut.

Credits and Links

HebCal  by Danny Sadinoff a UNIX (Linux and Solaris)  product ported to Windows.
http://www.sadinoff.com/hebcal
Congratulations Danny, well done.  The code has been thoroughly studied and used as an excellent source of information.

Chelm.org's explanation of the Jewish Calendar
http://www.chelm.org/jewish/calendar/explain.html
Copyright 1999 Steven Ross Weintraub
A clear and comprehensive explanation, even a code provided. Unfortunately the code doesn't work before year 1760 C.E., and apart from that, the logic for Rosh HaShanah calculation doesn't look 100%  accurate to me.
Judaism 101. Jewish Calendar

http://www.jewfaq.org/calendar.htm
Copyright 1995-2001 Tracey R Rich
A very simple explanation of the calendar which doesn't pretend to be exhaustive, but might be sufficient for non-developers.

Orthodox Union
http://www.ou.org
A good source of information about Jewish history, culture, holidays. Contains Zmanim tables,  publications, and more.

Countries Calendar Reform
http://webexhibits.org/calendars/year-countries.html
You might wish to visit the page to find out the date when Gregorian calendar was adopted in your area,
 

Releases

New to version 1.1 (14 Iyar 5765 / 23 May 2005)

• Support for touchscreens (such as stylus devices like Sony-Ericcson P800, Nokia Series 90, Motorola 388, etc). Refer to Using a  pointer device (stylus) .
• Hebrew release (translation by Daniel Sebbagh ),  and native format for Hebrew dates, partially supported by the English release - see  Representing Hebrew numerals in native format

From the original release

Current and the only version is 1.0. Today is 10th of Kislev 5764 ( 5 Dec 2004). Let it be a Chanukah present for the Jewish community all over the world ... and another chance to oppose Microsoft ® expansion (J2ME is one of very few platforms completely free of Microsoft interference).
 

Support

The application web site is  http://molad.palmcrust.com

For our other (commercial and free products) for Palm and mobile devices see http://www.palmcrust.com

Being interested in Jewish culture, I am not a religious person, have no religious friends, and don't visit a synagogue. This is why your comments are so important to me. Please, send me your suggestions, bug reports, etc to palmcrust@yahoo.com .  You are strongly advised not to use this address for anything not related to our software.  The mail box quite often runs out of quota, in which case we are unable to attend a really valuable message.

The code has been developed using j2mewtk v 1.4 and 2.0  for Linux with Nokia Series 30 and 60 MIDP Concept SDKs, and occasionally tested on real devices as well as with Windows-only emulators like Nokia Series 40, Motorola and Siemens. The manual has been prepared with Netscape 7.02 composer and HTMLDOC for Linux.

For developers

Another package contains the text classes used by the application.  If you want to translate Molad to another language, just replace the text in the classes and send the updated files to me. Please, try to avoid the translation being longer than the original text.

How the calendars operate

Hebrew calendar

In the Great Beit-Din, the chief Rabbi sits in his honored place, greeting the Jew who just arrived in the court. "I saw the moon last night, Rabbi, and I believe it is the beginning of a new month," reports the Jew.  The Rabbi motions to a chart with many different moon shapes hanging on the wall. "Is this the shape you saw?" asks the Rabbi, pointing to a particular shape. The man who witnessed the moon would be questioned until the judges were satisfied. When the judges heard proper testimony from at least two witnesses, they would declare that a new month had arrived

That's how the calendar worked in good old days, until Hilel II established a fixed calendar in the year 359 C.E.

Current Hebrew Calendar (H.C.) is a synthesis of astronomy, mathematics, religion ... and creativity.

It is a lunisolar (moon + sun)  clarendar  based on the following facts:

1. The lunar month (time between two consecutive new moons) is 29 days 12 hrs and 793 parts (chelekim) , each part being a 1/1080 of an hour.
2. 235 lunar months are equal in duration to 19 solar years.

A year cannot be purely lunar, otherwise holiday seasons would drift. Relation 2 yields the average number of  lunar months in a year as  235/19  or   12 7/19.  In the Hebrew calendar a "regular" year has 12 months, but whenever the accumulated fraction jumps over a whole number (i.e  f*(y-1) < N <= f*y,  where f=7/19 ,  y-year number, N-a whole number (***)) , an additional month is added to a year.  A year with an additional month is a leap year . In a leap year the last month Adar (29 days) is replaced by two months: Adar Alef (Adar 1) of 30 days,  and Adar Bet (Adar 2) of  29 days. Simple mathematics show that leap years are 3rd, 6th, 8th, 11th, 14th, 17th and 19th in a 19-year cycle, so that each cycle has 12 non-leap and 7 leap years.  (Indeed, 7 and 12 are special for any occasion !)   Please note that the last month in the calendar is not the last month of a year: a new year (Rosh HaShanah) starts at 1 Tishri, just in the middle of a calendar year - after all, a tricky nation can afford a tricky calendar :).

(***) In fact we  don't need to keep the old fraction!  Since 19 is a prime number, a fraction like (7*y)/19 jumps over a whole number if an only if the remainder (7*y) % 19 gets less than 7.

Remember extra 793 parts in the lunar month ? Something has to be done about that. The solution provided by the calendar is pretty straightforward: calculate the exact time of a new moon (molad) for Tishri (the new year month), if it is noon or afternoon, the new year (Rosh HaShanah) is postponed one day.  Well, it looks really simple ...  and too simple to be the case. There is also a requirement that some holidays should not fall on a particular day of a week, like Yom Kippur must not be adjacent to Shabbat (i.e. cannot be Yom 6, or Yom 1),  and Hoshanah Rabah should not fall on Shabbat. These dehiot adjustments might also result in Rosh HaShanah being postponed. See the source code for the details.

In order to postpone Rosh HaShanah, a day is added to Cheshvan, extending it to 30 days. Since year extension is not always astronomically justified, the following year might need to be reduced by one day to keep in path with the solar year.  To do that a month is taken from Kislev leaving it with 29 days. Note that only one of the two months can be altered.

Any questions so far ?  I have one. How was it possible to calculate all that without a computer ?  :=)

---------------

Few more remarks not related to the calendar algorithm, but still might interest someone.

1. Relation 2  (19 solar yrs = 235 lunar mnth)  is named Metonic cycle after Greek (Athenian) astronomer Meton (4th century C.E.), but  there is a striong evidence that this relation was known to  Babylonian and Chinese astronomers before Meton.
2. Combining facts 1 and 2 we can ewvaluate solar year as 365 days and 5 1847/4107 hrs, or 365days 5 hrs 26 min 58.92 sec, where according to the current astonomic data  this is 365.242199 or 365 days 5 hours 48 min and 46 sec, which ieven less accurate than Julian calendar. I haven't heard about forthcoming reform of Hebrew calendar though :)
3. The Bible refers to months by numbers, not by names, and (as far as I know) there is no eveidence to find out how the caledar was organised at that time. But there is a certain evidence that Babylonian calendar used 19 year cycles with 12 years of 12 months and 7 years of 13 months, and the Babylonian names of months (Nisanu, Ayaru, Simann, Du'uru, Abu, Ululu, Tashritu, Avakhsamna, Kislimu, Tebetu, Shabatu, Adaru) sound very similar to Hebrew months, BTW can you guess was was the name of 13th month ?   Adaru-2 ! Actully there is a strong belief that current Hebrew calendar is actually derived the Babylon and adoped probably during Exile in 6th century B.C.E..

Julian and Gregorian Calendars

By 7th century C.E. the Christian world started counting years from the birth of Christ (H.C. year 3761), what is referred as Common or Christian Era (C.E.) in Jewish terminology, while dates  'Before Christ' are referred as Before Common Era (B.C.E).  Please note that there is no year 0, so that year  1 B.C.E.  is followed by year 1 C.E.

The actual solar year is "only" about 365 days 5 hrs and 48 min and 46 sec. This gives extra 11 min 14 sec per a year, or extra 3 days in 4 centuries. This suggests that number of leap years is 4 centuries should be reduced by 3. In the 16th century C.E. the vernal (Spring) equinox felt on 11th of March, i.e, 10 days before the calendar equinox day, which could no longer be tolerated. The new calendar, developed under the leadership of Jesuit mathematician and astronomer Christoph Clavius only slightly differs from Julian calendar. Any multiple of 100 would correspond to a leap year in Julian calendar, whereas in the new calendar for a leap year it must also be a multiple of 400.  Thus years 1600 and 2000 are leap years, whereas years 1700, 1800 and 1900 aren't.

The new  Gregorian calendar was introduced in 1582 by Pope Gregory XIII who ordered that 4th of October was to be followed by 15th of October. That dropped 10 days from October and re-established the consistency of solar and calendar years. The reform took place in Italy, Poland, Portugal and Spain, other catholic countries soon followed. In England and colonies (including Ireland, and Eastern part of USA)  Gregorian calendar was introduced in 1752 (2 Sept. followed by 14 Sept.), while Christian orthodox countries adopted Gregorian calendar not until 20th century (Russia: 31Jan1918- 14Feb1918,  Greece: 9Mar1924-23Mar1924).

For the complete list of calendar reform dates see  http://webexhibits.org/calendars/year-countries.html
 

Representing Hebrew numerals in native format.

Using the Application

Terms Explained

Phone Keys

T9 layout

[1]  [2]  [3]
[4]  [5]  [6]
[7]  [8]  [9]
[*]  [0]  [#]

Some expensive models (Sony Ericsson P800, Nokia Series 90, Motorola 388) a designed to be used with a stylus, something the application currently does not support.  However in some cases there is a way around. For example P800 has buttons labeled  [A] [B] [C] [D] translated to corresponding game keys
 

Other Keys

Commands

Date View ("calendar") Screen

Date View Data

Dates

The arrow in the middle of Date panel shows current navigation calendar:

->  Hebrew calendar is current
<-  Common calendar is current

Information Bar

Indicator is one of  the following  letters:

J - Julian calendar (if omitted , then Gregorian calendar is used)
L - Leap year. Left L refers to a Common leap year, while right L denotes Hebrew leap year.

Day count is either an Omer day (Sefirat HaOmer starts after Passover/Pesach and ends before Shavuot), or a day in 3-week period between two fasts (17 Tammuz and 9 Av), or a day from Rosh HaShanah if neither Omer nor 3W apply.  Omer and 3W days are shown if 'show Omer/3W' is enabled in Settings, in which case a special colour is used for Omer/3W pages.

The information bar for a Shabbat day might be extended with Shabbat names (like Shabbat HaGadol being the last Shabbat before Pesach), or  weekly Torah readings (sedrot).  For that you need to enable respectively  'show Shabbat' and/or  'show Sedrot' in Settings.

Events

Controlling Date View Screen

Date View Commands

Multiple Pages and Auto-Turn Page

You can specify Auto-Turn Page option, in which case page will is turned automatically every 4 seconds.
 

Date Set Screen

You can call Date Set to select either Hebrew or Common date. Since only one date is shown, navigation calendar is not applicable to Date Set screen.

Date Set screen is also used to specify the last Julian date for Settings .

Controlling Date Set Screen

Date Set Commands

The  application accepts dates in a range from 1 Tishri 1 to  29 Elul 5000000, which corresponds to  7 October 3761 B.C.E. Julian  to 1 November 4996299 C.E. Gregorian. Please note that year 0 is never accepted  since (as mentioned before) year 1 B.C.E. is followed by year 1 C.E. 

Using a pointer device (stylus)

Touchscreen devices usually come with a pointer device(stylus) and often don't have a T9 style keypad, which might complicate the control Date View ,   Date Set and Event Date Setup screens. In fact, you can control these screens through menu, but it is not as convenient as  with keypad.

Starting with v 1.1 the application allows controlling the above mentioned screen also with a stylus, however this does not exclude the use of keypad. For example, some stylus devices have Game Keys that can be used along with a stylus. The application automatically recognises a touchscreen device and shows Pointer Navigation help  before common help information, if relevant.

The use of stylus to be rather intuitive. In order to advance to next day/month/year, you just tap the  right side of day/month/year respectively on the screen. Similarly, in order to get to previous day/month/year you tap the left side of day/month/year resp. In Date View screen you can navigate by Hebrew or secular date, depending on which day, month, or year is tapped.

Tapping day of week(DOW) or other "hot spots" is processed specifically to the screen displayed, as the following:

Taping other spots shows Help screen.

Settings Screen

To change an item press FIRE key or enter Select command. Some item (Location, Navigate, List) change value "on fly" others will bring up a separate screen.

Settings Screen contains the following items:

Holidays and Custom Events

Event Display Options

Comments:

1. Highlight and Erev imply Display
2. An event never appears as 'Erev' in a list of Coming/Past events.
3. An event listed as Erev does not cause page highlighting, but its name is typed highlighted, if Highlight is enabled.
4. A Katan Event is not highlighted, but other settings apply. In  particular List enables listing Katan Event  in Coming/Past, while enabling Erev will produce a line like 'Erev MyEvent Katan'  for  the date preceding Katan event.

Customising Holidays

To specify display options for a holiday:

1. From Date View screen enter Settings command  (or press [1] key)
2. In the list of settings select Holidays and press FIRE key. This brings up the list of holidays, where each  holiday is shown with  initial letters of enabled display options
3. Select a holiday you wish to set up and press FIRE key get the list of options.
4. Press  FIRE key to enable/disable highlighted option in the list, enter Close when done - the new options are now effective. Please note, that Display will be actually disabled only in case both Highlight and Erev are also disabled.

Custom Events

• Event Name (up to 20 chars)  used for Date View page
• Event Short Name - used for event lists and compound names (i.e with Erev and/or Katan)
• Event Date:  Hebrew day and month,  number of days (1 by default)
• Display options, see Event Display Options

1. From Date View screen enter Settings command  (or press [1] key)
2. In the list of settings select Custom events and press FIRE key. This brings up the list of custom events

To add or edit an event, select an event (New Event ...  for adding) and press FIRE to get Event Setup screen.  You can go straight to event options by entering Set Options comman. To delete an event enter Delete command.

Event Setup screen shows event names, event date and options.  Use UP and DOWN key to navigate between event names and options (some devices might have it in a different way).

Default display options of a custom event are Listed, Displayed. To edit display options enter Set Options command. This brings up Display Options setup screen similar to the one used for customising holidays .

Event date is initially set to the day and month of the active (last viewed) date - the date shown on Date View Screen before  Settings command was entered. To change the event date enter Set Date command - this brings up Event Date Setup screen.

The following keys are used with Event Date Setup screen:
 

Comments:

1. Adar events are celebrated in AdarA during leap years. For AdarB events see Adar Bet Events
2. It is assumed that Cheshvan, Kislev and Adar have 30 days. In years where a month has  29 days, the event assigned to 30th of the month takes place at 29th of the month
3. Number of days is normally shown only of more that one. However, with a touchscreen device number of days always appears, so that you can set it with a stylus, see Using a  pointer device (stylus) .
   

Adar Bet Events

If you are lucky enough to be born or married in AdarB, you can follow Purim tradition and celebrate your remarkable date twice in a leap year.  To do that you set up a custom event for AdarB, and enable Katan as display option (see Event Display Options )