Shalom if one wants to hold the latest Zman for the end of Shabbos, which I believe is the Rabbeinu Tam is this 72 minutes after candle lighting, or is it 72 minutes after Shkiah ie,,,Candle Lighting + 18 minutes + 72 minutes, and if someone wishes to do Tosfos Shabbos another couple of minutes after that. Many Thanks. Yitzi Rose
Shalom, Thank you for your question. First let me say that generally the times for taking Shabbat out are publicised on major Jewish calendars (and websites today – for example “myzmamnim.com”) for most locations in the world, and you can certainly rely on those times. Usually they publish one time for taking Shabbat out, and then a later time under the heading “Rabbainu Tam”. As to your question – Rabbainu Tam time is the time it takes to walk four “mil”s after sunset. Most opinions hold that the time it takes to walk one mil is 18 minuets – and that is the generally accepted calculation of Rabainu Tam time (and all halachic time), giving us 72 minuets. But some say it is 22.5 minuets for a mil, giving us 90 minuets after sunset for Rabanui Tam time, which some people do hold by. Additionally, there is a question as to whether this time of “4 mils” changes according to location and season. That is, does the 72 minuets (or 90 minuets) refer to an astronomical calculation based on the position of the sun in Jerusalem on the midpoint of the year [equinox] (the sun being 16.1 degrees below the horizon)– or is it a standard time in every location and all through the year. After Shabbat one also waits an additional few minuets for “Tosefet Shabbat”. On exacting calendars these times can be found. I stress that the generally accepted times for the departure of Shabbat that are printed in the local calendars etc, and followed by many fine communities, are perfectly acceptable. If you still want to follow Rabainu Tam to the strictest interpretation, then my advice to you is to follow the standard practices of those who hold Rabbainu Tam in your area and to use their calendar times. If you none the less want to be extra strict, then you could follow the opinion that holds 90 minuets from sunset, that is 108 minuets (or 1 hour and 48 minuets after candle lighting – and you could round it up to 1 hour and 50 minuets to include Tosefet Shabbat). Blessings.