MyZmanim Air: Calculating in-flight zmanim based on actual flightpath data.

Davening and Other Halachic Issues While Traveling by Air

Many halachic issues arise when traveling by air. One of the most common questions STAR-K receives concerns about davening and other time bound mitzvos while in flight.

Empowers air travelers to daven and lay tefillin in the proper time. Using advanced aircraft tracking technology, MyZmanim reliably calculates in-flight zmanim based on actual flightpath data.

MyZmanim Air

Many observances in Jewish law must be performed at specific times during the day. This can be a major challenge when traveling on flights, as you never know exactly where you’ll be at what time.

This app uses Rabbinically reviewed zmanim and highly accurate flight path information to provide you with the latest in-flight zmanim. Unlike other apps that simply display pre-calculated times, these zmanim are generated based on the actual position of your aircraft at any given moment during the flight.

The zmanim used in this application are calculated using Eliyahu Hershfeld’s KosherJava zmanim API, which has been rabbinically reviewed. The flight path calculations used to project when the zmanim will be reached use R’ Chaim Keller’s famed Chai Tables code. The result is that the app’s zmanim are more accurate than any other available in-flight zmanim.

MyZmanim Calendar

Thousands of users around the world rely on MyZmanim to fulfill their time-bound mitzvot. Whether in shul, on the beach or in the air, MyZmanim gives Jews the tools they need to serve Hashem.

MyZmanim displays all astronomical times (Zmanim) in your local timezone. For your convenience, times for sunrise, sunset, and earliest tefila are displayed as rounded times. The rounding is based on lechumra and the JavaDocs for the ZmanimCalendar.

A flight leaving Eretz Yisroel heading due east will have sunrise less than 2 hours into the flight. This makes the sof zman krias shema very short and requires a careful look out of the window to make sure it is daytime.

In order to ensure that the correct Jewish date is displayed and the molad times are accurate, you must select the year. This will also ensure that the correct start and end of daylight savings is reflected. If you don’t select a year, the MyZmanim calculation will use the USNO algorithm which is not as accurate for dates close to leap years.

MyZmanim Alerts

While most airlines have a good in-flight zmanim chart, the accuracy is limited by the fact that they only provide precalculated charts based on the flight’s origin and destination. These charts are based on great circle routes that do not take into account actual flight paths (which in many cases fly east or west of the original route).

Using advanced aircraft tracking technology, MyZmanim collects and stores real-time flight path data to reliably calculate in-flight zmanim for most commercial flights. The result is a mobile application that shows the time to upcoming zmanim, recalculated multiple times a minute to compensate for headwinds and tailwinds, as well as in-flight route changes.

Additionally, the app displays a compass bearing to Yerushalayim/Jerusalem that enables shuls and organizations to easily display the zmanim info on their websites by simply copying a block of code. The app also provides a number of local access numbers to the zmanim info, and includes an easy-to-use widget for display on the home screen of mobile devices.

MyZmanim API

Every day the STAR-K office and the Institute of Halacha receive inquiries from STAR-K mashgichim and travelers about in-flight zmanim. The most common questions are about davening and other halachic issues impacted by changing time zones during flight.

Many programs, including the STAR-K Chai Air Times program, try to solve this problem by precalculating a great circle route between your origin and destination locations and then comparing that against your actual flight path. However, this method is not very accurate.

MyZmanim Air overcomes this problem by displaying zmanim based on your aircraft location, which changes at various points during the flight depending on wind conditions. It also takes into account a number of other factors, such as when the aircraft crosses over the Arctic Circle and the halachic dateline. Moreover, the application displays zmanim in two separate data sets for bi-directional flights so that you can be prepared whether you are flying east or westbound.

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