A screen you cannot interact with has to be understood at a glance, which only works if you already know what you are looking at. These are longer written explanations of the things Shabbat Screen puts in front of you — the meteorology behind the forecast panels, the astronomy and custom behind the zmanim, the arithmetic behind the Hebrew dates, and the unglamorous device settings that decide whether a display survives twenty-five hours untouched.
Feels-like temperature, relative humidity, dew point, probability of precipitation, UV index, wind, barometric pressure and cloud cover — what each one measures, what counts as a normal value, and the misreadings almost everyone makes. Includes why 40% chance of rain does not mean light rain, why 95% humidity at dawn means nothing, and why the dew point is the number to read instead.
Both times are built from sunset at your exact coordinates plus a customary margin. This covers the 18-minute standard and the Jerusalem 40-minute custom, the two competing methods for fixing nightfall, why twilight lasts longer at high latitude, what happens in northern cities where the calculation has no solution in summer, and the five reasons two calendars can print different times for the same city.
Every setting that has to be right before candle lighting, because none of them can be fixed afterwards. Step-by-step for iPad, Android, Amazon Fire, Windows, macOS and Raspberry Pi, including kiosk-mode commands, the automatic-update restarts that quietly kill overnight displays, and practical notes on OLED burn-in, battery ageing and heat.
The Hebrew calendar reconciles lunar months with a solar year, and the machinery is remarkable. The nineteen-year cycle, why the leap month is called Adar I but is the added one, the molad and its 1,080ths of an hour, the four postponement rules, the fourteen possible shapes of a year, and the slow drift that will matter in a few thousand years.
The setup walkthrough: choosing a location, picking panels and refresh intervals, selecting news sources, setting units, theme and language, and what keeps updating on its own once you walk away.
Short answers to the common questions — cost, installation, supported devices, refresh behaviour, location handling, news sources, languages, and use on Yom Tov and chol hamoed.
They are written by hand, by the person who built the screen, and they exist because the questions kept arriving by email. Nobody needs another page repeating that rain is wet; what people actually wanted to know was why their calendar disagreed with the shul's by four minutes, and why their tablet was blank on Saturday morning. Each guide is the long answer to a real question.
If something here is wrong, unclear, or missing, the “Contact Us” link in the footer of the main screen opens a form that reaches me directly. Corrections are welcome.