Ezekiel 32:7-8"And when I shall put thee out, I will cover the heaven, and make the stars thereof dark; I will cover the sun with a cloud, and the moon shall not give her light. All the bright lights of heaven will I make dark over thee, and set darkness upon thy land, saith the Lord GOD."
Joel 2:10, 30-31"The earth shall quake before them; the heavens shall tremble: the sun and the moon shall be dark, and the stars shall withdraw their shining. And I will shew wonders in the heavens and in the earth, blood, and fire, and pillars of smoke. The sun shall be turned into darkness, and the moon into blood, before the great and the terrible Day of the LORD come."
Matthew 24:29-30"Immediately after the tribulation of those days shall the sun be darkened, and the moon shall not give her light, and the stars shall fall from heaven, and the powers of the heavens shall be shaken: and then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of man coming in the clouds of heaven with power and great glory."
Revelation 6:12-13"And I beheld when he had opened the sixth seal, and, lo, there was a great earthquake; and the sun became black as sackcloth of hair, and the moon became as blood; and the stars of heaven fell unto the earth, even as a fig tree casteth her untimely figs, when she is shaken of a mighty wind."
It is significant to note a couple of things: 1) All Feasts of Passover and all Feasts of Tabernacles occur two weeks after the New Moon (mid-point in the months of Nisan and Tishri); and 2) The context of the four passages varies in relationship to various points in Israel's history, past and future.
I don't know what the Tetrads mean, but these passages are not referring to them.