Are the 3 hours before sunrise an auspicious time for praying in general like it is for selichos? What are the sources?
Answer:
The three hours at the end of the night are auspicious for prayer, a principle based on the Gemara in Berachos where it is stated that during the last three hours of the night Hashem “hovers” in the world.
However, the main point that poskim are makpid about is that the selichos should be said after chatzos, and not before.
For sources on the matter, which are mainly drawn from kabbalah, see Shut Yecheveh Da’ah 1:46; see also Iggros Moshe, Orach Chaim 2:105, who points out that the principle sources on the issue of based on kabbalah, and is therefore lenient, where there is a need, to recite selichos even before chatzos (see also here for more details on this point).
