We know that selichot are generally recited either after chatzot (halachic midnight) or before davening in the morning. Some shuls have the practice of allowing a minyan for selichot to take place earlier in the evening, usually some time around 9 or 10pm. Is such a practice permitted? We will look at two recent teshuvot that take divergent views not only on the answer, but also on their approach to the answer.
Rav Moshe Feinstein was asked this question in the context of individuals who lived in a location where they were afraid to be out on the street alone at the usual times for reciting selichot. As such, they wanted to recite the selichot at an earlier time in the evening, when there were more people around and the danger was decreased. Rav Moshe's answer, which follows through the Shulchan Aruch and its major commentaries, is that the purpose of reciting selichot after midnight is because that it considered to be an עת רצון and thus it is the most appropriate time to beg for mercy from Hashem. However, since this entire practice has no basis in the Gemara and is based mainly on Kabbalistic literature, Rav Moshe felt it was better to allow selichot at an earlier time rather than to have people not say them at all. Rav Moshe even brings sources which seem to cast doubt on the specific efficacy of chatzot. However, he does caution that this ruling should be seen as a הוראת שעה and that if the situation improves, and certainly for people who do not have such a problem, selichot should be recited ater midnight.
Rav Ovadiah Yosef tackles the problem in a completely different manner. For him, the Kabbalistic sources are all-important, and the lack of a Talmudic basis for selichot does not factor into his reasoning at all. He explains that according to the Zohar, the time from the afternoon until halachic midnight is a time of מדת הדין - judgement, and only after midnight does Hashem switch his focus to that of רחמים - mercy. Thus, saying selichot before midnight would be both pointless as well as borderline heretical, and any location which has such a minyan is engaged in a bitter and bad practice. Rav Yosef quotes Rav Moshe Feinstein's dismissal of the Kabbalistic basis for this practice and says instead that the Kabbalistic rationale is so strong and so important that one ignores it at his own peril.
Rav Yosef further deals with two challenges. First, if the evening is a time of judgement and thus unfit for the recital of selichot, then how do we explain the common practice to say selichot in the evening of Yom Kippur? Rav Yosef brushes this objection aside by explaining that Yom Kippur is different, as the entire day is one when Hashem is open to hear supplication.
Second, what does one do it he is unable to recite selichot after midnight or in the early morning? Rav Yosef suggests reciting them before mincha. As to the possible objection that he said earlier that the afternoon is a time of judgement, Rav Yosef qualifies that position by noting that many people begin תחנון at mincha by saying וידוי and the י"ג מידות הרחמים, which are the essense of selichot, and thus they must have some efficacy at that time.