FAQ and Disclaimer
- What zmanim are displayed and how are they calculated?
- How reliable are these times? Why is it that other sites display slightly different times than this one? Why do I see such major discrepancies all of the place with regard to earliest time for Talit?
- What does "beta" mean, and why is this calendar "beta"?
- I'm having some trouble with the calendar!!
- What features does this calendar provide?
- How do I change my location? Why can't I find my location? Is there a special format for entering in cities?
- Where is Yerushalayim?
- Why can't I see the time for ______ according to _____?
- I live in Jerusalem, and the time for candlelighting is wrong!!!
- I live in Israel, and I see the Diaspora holidays!!!
- What zmanim are displayed and how are they calculated?
The two most important zmanim we display are sunrise (netz) and sunset (shkiah). These are calculated through a public domain algorithm which is used on other websites as well. Dawn (Alos) is calculated as being 72 minutes before sunrise and nightfall (tzeit) is calculated as 72 minutes after sunset. The time for earliest Talit and Tefillin is assumed to be when the sun is 10.2 degrees below the horizon. The day is split into 12 portions, starting at sunrise and ending at sunset, and those 12 portions (halachic hours) are used to calculate the latest time for recital of the Shema, the latest time for recital of the morning prayers, midday, the earliest time one may pray the afternoon service, the optimal time (according to some) for reciting the afternoon service (mincha ketana), and plag hamincha.
The time for Havadalah displayed on the calendar is 42 minutes after sunset, and on the grid view we display 42 minutes and 72 minutes.
- How reliable are these times? Why is it that other sites display slightly different times
than this one? Why do I see such major discrepancies all over the place with regard to
earliest time for Talit?
An important note must be made about the times for sunrise and sunset. Here is a quote from the United States Naval Observatory Web Page: http://aa.usno.navy.mil/faq/docs/RST_defs.php
The times of rise and set phenomena cannot be precisely computed, because, in practice, the actual times depend on unpredictable atmospheric conditions that affect the amount of refraction at the horizon. Thus, even under ideal conditions (e.g., a clear sky at sea) the times computed for rise or set may be in error by a minute or more. Local topography (e.g., mountains on the horizon) and the height of the observer can affect the times of rise or set even more. It is not practical to attempt to include such effects in routine rise/set computations. The accuracy of rise and set computations decreases at high latitudes. There, small variations in atmospheric refraction can change the time of rise or set by many minutes, since the Sun and Moon intersect the horizon at a very shallow angle. For the same reason, at high latitudes, the effects of observer height and local topography are magnified and can substantially change the times of the phenomena actually observed, or even whether the phenomena are observed to occur at all.
In other words, it is impossible to determine the exact time, in any location, for sunrise and sunset, even if we determine the elevation of that particular location. Other sites may use slightly different algorithms for calculating sunrise and sunset, and therefore there may be discrepancies in times. None of the authors of those sites will claim that one can rely on their times to the minute, and one should never do that. The time for earliest Talit is known in halachic literature as "MiSheyakir", and is described as the time when there is enough light to recognize one's friend from a distance of 4 cubits (approximately 6 to 8 feet, depending upon one's definition of the size of a cubit). Obviously, it is extremely hard to objectively give a time for when this is, and there are a huge array of opinions which are split into two camps: Those that use a fixed time, which is anywhere between 66 and 36 minutes before sunrise, and those that use a time based on the solar depression which is when the sun is between 11 degrees to 10.2 degrees below the horizon. Since it is impractical to supply all the times, we have chosen to display the time when the sun is 10.2 degrees below the horizon. Rabbi Belsky, one of our poskim, has told us that he refuses to give a final decision on how one should rule on this issue, and advices that everybody should consult with their local community Rabbi.
- What does "beta" mean, and why is this calendar "beta"?
Beta, the second letter of the greek alphabet, is a name attributed to software which has undergone rigorous internal testing by the developers, but likely still has some kinks and problems, especially useability issues, waiting to be discovered by users who will use the program in manners not anticipated by the public. A "beta test" is run to allow the public at large to discover problems and "bugs", and to suggest additional features so that a final "stable" release can be created. In addition, the developers get an idea of how outsiders expect the software to work, especially those without a technical background. Please see this article for additional details.
- I'm having some trouble with the calendar!!
If you're having trouble with the calendar, first read through this FAQ to see if your question appears here. If not, we appreciate all feedback so that we can better improve the system in the future. There are a few things you should check before you respond.
Make sure that the location is entered correctly. For a location in the US, enter it in the format "New York, NY US" with the city, followed by a comma, the two letter abbreviation of the state, and the two letters 'US'. If it's an international location, just type something like Newbury, GB, the city name followed by a comma and the two letter country abbreviation.
When you start typing, a box with suggestions should show up so you don't have to type in the whole name of the city (eg., if you type in "new", you will see a list with the items "New York, NY US, Newbury, GB, Newark, NJ US, New Delhi, IN, New Orleans, LA US, New Haven, CT US, Newport Beach, CA US, Newark, DE US, Newark, CA US, New Brunswick, NJ US"), just as if you started typing something into your web browser's address bar. You can either select something from the list, or continue typing in order to narrow the selection.
If you are sure that you are entering your city correctly, and nothing is working, or there is some other problem, check to see if you have Javascript and Cookies enabled. You can check to see if you have Javascript enabled by typing javascript:alert("hello") into the address bar of your web browser. If you have Javascript enabled, you will see a box popup with the message "hello".
If you still feel the need to contact us, it is crucial that you provide us with what browser you are running, and what version of that browser you are running. You can find this information by going to the "help" menu, and clicking "about".
- What features does this calendar provide?
At its current stage, the calendar is divided into three parts: Zmanim and Holiday information, community information, and daily learning. The location for which the information displayed pertains to can be changed at will by the user by entering a city, or a zip code (currently US only), into the box labeled "To change location, type city here:". We try to ascertain the user's location using a process called "geoip" which, to put simply, looks up the current visitor's internet address (known as an IP Address) in a database which lists address ranges with city, region and country information. It is over 90% accurate, but there are some issues which may cause it to not find the correct location (eg., the popular America Online service masks a user's true IP address with another one, so we can not accurately determine the location).
Under the "Calendar and Local Zmanim" header there is the Calendar View tab which displays the holidays, Torah portion of the week, Candlelighting and Havadalah time where appropriate. The current day is highlighted to display sunrise, sunset, the latest time to recite the Shema (according to the more lenient opinion of the "Gra", and the latest time one can recite the morning prayers. Each date on the calendar can be clicked to reveal more detailed zmanim for that particular date.
The tab labeled "Grid View" provides a monthly "grid view" of all the zmanim for the currently selected month, convenient for printing out a monthly view of the zmanim. Information about the holiday cycle for any given year can be found under the tab labeled "Major Holidays". Here one can find the dates for the major holidays falling out in the selected English year and the following year, as well as basic information about them, such as if there are any work restrictions involved.
Under the Local Community Information heading can be found maps of shuls and mikvahs in the current selected area, as well as jobs which are in the current selected state. Calendar listings of the Daf Yomi and Nach Yomi schedules can be found in the tabs under the Daily Learning heading.
- How do I change my location? Why can't I find my location? Is there a special format for
enter cities in to the search box?
In the box labeled "Change your location:", you can type in a zip code or a city location. To help assist the user, when a few characters have been entered a box of suggestions will drop down. The user can either continue typing in order to narrow down those suggestions, choose one that appears, or continue typing without using the suggestions. If one chooses to type in a city, without utilizing the suggestions, the format for a city in the United States or Canada is [city name], [state] [country code]. So for instance, if one wanted to lookup Wahoo, Nebraska, they would type "Wahoo, NE US" or Dundas, Ontario would be "Dundas, ON CA". A city in an international country would be entered in the format [city name], [country code] , so Jerusalem can be found by typing "Jerusalem, IL".
If your particular city of interest doesn't show up, perhaps try typing in the postal name of that city. For instance, the neighborhood of Kew Gardens Hills, NY does not show up, but its postal name, Flushing, does. Failing that, try looking up a neighboring city, since the difference in zmanim is negligible between neighboring cities.
- Where is Yerushalayim?
Our input accepts only the English spellings of cities so you'll have to type in Jerusalem.
- Why can't I see the time for ______ according to _____?
There are many different opinions regarding how to calculate certain zmanim. For example, some say that dawn is 72 minutes before sunrise, some say it is 90 minutes and some say it depends on the position of the sun. We felt it that it would be more beneficial to just list the most prominent opinions as opposed to an overwhelming menu of different choices.