1. General
  2. Ideas
0
Completed

How Are Zmanim Calculated

YitzyB 3 years ago • updated by Michael J. Radwin 3 years ago • 1

Hi I have been thanks so much for this API, its amazing! I'm using it to generate an erev shabbos calendar. (Using the Zmanim API because I wanted Plag too) I was reading up on some documentation for calculating times of day and from what I have seen there seem to be two ways to calculate sunrise and other times of day. The USNO (US Navel Observatory), and the NOAA (National Oceanic and Atmospheric Administration). Which one is used by HebCal?

I see a similar question was asked 4 years ago and was not addressed. So if you can please shed some light (no pun intended) I would greatly appreciate it.

Answer

Answer
Completed
Michael J. Radwin 3 years ago

Hi, thanks for using Hebcal and thanks for the question!

Since one year ago (August 2020) our sunrise/sunset algorithm is based on NOAA. There is a little more detail about our implementation here:

https://www.hebcal.com/home/94/how-accurate-are-candle-lighting-times

Answer
Completed
Michael J. Radwin 3 years ago

Hi, thanks for using Hebcal and thanks for the question!

Since one year ago (August 2020) our sunrise/sunset algorithm is based on NOAA. There is a little more detail about our implementation here:

https://www.hebcal.com/home/94/how-accurate-are-candle-lighting-times

Customer support service by UserEcho