Avinu Malkeinu as part of Tachanun
I know the following:
The word "considered" will surely invoke the response "by whom." I have no answer but want to know the breadth of opinions.
The question begs "what does it matter?" I have yet to figure out if it does at all matter (other than to clarify the order of prayers), but I'm curious at this point.
In my siddurim, there is a set of vidui, confession, printed right after the morning Amida. Then comes Avinu Malkeinu, and then Tachanun. The Artscroll siddur I happened to use this morning comments that "The custom of confessing as a prelude to Tachanun is based on the Zohar." But then what follows is Avinu Malkeinu (labeled as such) and then, on page 124, the section entitled "Tachanun."
Is Avinu Malkeinu considered part of Tachanun which is why we would say Vidui before it or is it not, so we should be saying Vidui AFTER it on fast days, so that the confession is a prelude directly preceding the actual tachanun?
[this Q seems to hint to a possible disagreement in whether it is or isn't]