Zevachim 20: Location, Sanctification and Immersion

Some basic ideas from today's daf:

• must the basin's water be changed every night so that it does not sit and become disqualified for sanctification?
• the bull should stand with its head to the south and it's face turned to the west; the priest stands to the east of the bull and faces west when he puts his hands over the bull
• What is north?  The rabbis say that north is from the northern wall of the altar to the northern wall of the Temple courtyard
• The rabbis discuss whether a priest should sanctify his feet a second time in one day if he first sanctifies his feet for the ashes
• Must a priest sanctify his feet a second time if he leaves the Temple after the first sanctification?
• A priest who reenters the Temple after leaving to "cover his legs", which is a euphemism for having a bowel movement, must immerse and sanctify his hands and feet first
• A priest who reenters the Temple after leaving to urinate must sanctify his hands and feet first
• If a priest becomes ritually impure, he is sometimes permitted to immerse his feet without also sanctifying them before entering the Temple 
• The rabbis look at ritual slaughter that occurs outside of the Temple to discuss when sanctification is required