What are all the halachic opinions for when to do havdalah? I'm writing a calendar and I want to provide all the options that people use.
The ones I've seen are:
- 42 min after sunset ??
- 72 min after sunset (Rabbeinu Tam)
- 7.5 degrees below horizon ??
- 8.5 degrees below horizon ??
- 8.75 degrees below horizon ??
(Note that I calculate sunset as a zenith of 90 + 50/60 degrees.) I don't really need every single option possible, just the ones that people actually use.