In my siddur (Shelah, Shaar HaShamayim) it says that tikkun chatzos (specifically tikkun Rachel) is not said on days were tachanun is omitted. On Tisha B'Av we do not say tachanun. However it is hard for me to believe that a tefilla specifically for mourning over the loss of the temple would not be said on Tisha B'Av! May a person say the entire tikkun chatzos on the night of Tisha B'Av?
1 Answer
The reason I believe we don't say tachanun on Tisha ba'av is because it is considered a holiday in Eicha because eventually we will celebrate Tisha ba'av as a holiday. According to this, one should still say it because at the present time its not a holiday and saying tikkun chatzot is still needed.
There are also two tikkuns ,tikkun Rachel Tikun Leah.
The Ben Ish Chai Shana Rishona Hilchos Tisha ba'av 25 writes: , גם בליל ט"ב אחר חצות אומרים תיקון רחל בלבד, אבל ביום אין אומרים תיקון רחל אע"פ שדרכם לאמרו בכל יום אחר חצות מיום י"ז תמוז ואילך, וכן ביום ערב ט"ב אומרים אותו ביום אחר חצות ועיין יוסף אומץ סי' כ"ה:
one should say tikun Rachel only, on Tisha Ba'av night,one should not say tikun Rachel during the day...