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Rosh Hashanah is always observed on the first two days of Tishrei, the seventh month of the Hebrew calendar. Rosh Hashana for Hebrew Year 5784 begins at sundown on Friday, 15 September 2023 and ends at nightfall on Sunday, 17 September 2023.

The rules governing how the calendar works were developed during the rabbinic period and were fully codified by Maimonides in the Mishneh Torah in the 12th century. It would be a mistake to look only at the Bible and ignore the rabbinic sources or Rambam.

You can read more about the Hebrew calendar on Wikipedia:

https://en.wikipedia.org/wiki/Hebrew_calendar

Hi, thanks for using Hebcal.

We offer a tool that lets you print a year’s worth of Torah readings and Shabbat times for your location:

https://www.hebcal.com/home/shabbat/fridge

Our website is digital only, so you can print out calendars downloaded from Hebcal.

The short answer is that if you are comfortable editing a URL, you can append something like ?ny=50 to the end of a download.hebcal.com URL to download 50 years at a time (the "ny" stands for "number of years").

1. Go to https://www.hebcal.com/hebcal

2. Fill out the form for your preferences (for example starting in 1973) and choose "Create Calendar"

3. Click the "Download" button and a modal will pop up

4. Select the "CSV" option

5. Right-click on the CSV download option and pick "Copy link address"

6. Paste the link address into your browser URL bar (but don't hit the enter button on your keyboard)

7. Append ?ny=50 to the end of the URL, then click Enter

The downloaded CSV file should cover the range 1973 - 2023.  Adjust the year in step 2 above per your needs.

Hebcal Salesforce integration sounds great!

There is no paid API. You are welcome to use Hebcal freely.

Here is some guidance in how to give credit to Hebcal

https://www.hebcal.com/home/4289/giving-appropriate-credit-to-hebcal

Thanks for using Hebcal!

To create a calendar with Israeli schedule, visit our custom calendar page at https://www.hebcal.com/hebcal and choose the "Israel holiday schedule" option instead of Diaspora, and make sure Rosh Chodesh is checked.

To enable alerts for Rosh Chodesh and other holidays, download/subscribe to the Hebcal calendar in your favorite calendar app. Go to the app settings and enable the option to alert on all-day/untimed events (see below for an example from the Apple calendar; there are similar settings in Outlook, Google Calendar, and other calendar apps).

Hi, thanks for using the Hebcal JavaScript library. 

Zmanim, Candle-lighting and Havdalah times are derived from sunset times, which are approximated from a location (latitude, longitude) and day of year. There is no way to include elevation in the Hebcal zmanim calculations because the underlying solar calculation algorithm doesn't use elevation.

The NOAA solar algorithm claims accuracy within 2 minutes except at extreme northern or southern latitudes. Adding elevation often changes the sunset calculation by 1 minute or less, so this is within the expected margin of error.

Hi, thanks for using Hebcal. We double-checked and the triennial divisions as published are indeed correct. The third triennial aliyah should be 1:8-10.

Our triennial aliyot divisions correspond with both the CJLS triennial divisions and the traditional full kriyah aliyot divions (the first full kriyah aliyah ends at verse 10).

For an explanation for why the aliyah concludes with verse 10, see below excerpt from the 5783 Luah Hashanah by Rabbi Miles Cohen (highlighting mine)