I usually keep a day Taanis as Assarah Beteveth is, from the second or later time for Alos Hashachar (daybreak and beginning of the day) mentioned in the Luach. As you and others mentioned Assarah Beteveth is more severe than other fast days. Should I then begin the Ta’anis from the earlier time? Please send a prompt answer. Thanks

There may be indeed a greater reason to be stringent on this particular Taanis, as mentioned in the questions above. Horav Shlomo Miller’s Shlit’a added that he keeps the early Alos time during all fast days.