According to Chabad:
According to the Etz Chaim of KGH bulletin:
According to MyZmanim:Sunday Dec. 23 - Fast of the Tenth of TevetBegins 6:05 AM, ends 5:14 PM
As usual, there is the three minute discrepency between Chabad and R' Tukaccinsky according to MyZmanim, based on computations based on elevations.
at 5:48 AM Dawn - Degrees
or at 6:05 AM Dawn - Fixed Minutes
Eating of a settled character - אכילת קבע - may not be started
during the half hour immediately preceding dawn. Please
consult your Rabbi for details.
The fast ends no later than the
emergence of ג' כוכבים בינונים at -
5:06 PM R' Moshe Feinstein
One who finds fasting difficult may eat at - 5:10 PM
One who does not find fasting difficult
should wait until the time for מוצאי שבת at -
Do not rely on zmanim times to the last moment.
Have an easy fast.