The 4 current blood moons are not signs of impending judgement. Peter quoting Joel 2 said "this is that" (being fulfilled in their generation living in the 'Last Days' of the old covenant Jewish order)....
“And it shall come to pass in the last days, saith God, I will pour out of my Spirit upon all flesh: and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams: And on my servants and on my handmaidens I will pour out in those days of my Spirit; and they shall prophesy: And I will shew wonders in heaven above, and signs in the earth beneath; blood, and fire, and vapour of smoke: The sun shall be turned into darkness, and the moon into blood, before that great and notable day of the Lord come: And it shall come to pass, that whosoever shall call on the name of the Lord shall be saved.” Acts 2:17-21
Question is when is or was the notable day of The Lord?? And, what is or was the notable day of The Lord?
Jesus in Matthew 21-24 and Luke 19:41-44; 21:15-22 'sets the stage' for the coming wrath (notable day of The Lord) of God. The blood of the prophets was the Reason judgement was coming upon Jesus contemporaries (This Generation Matt 23..... “Woe unto you, scribes and Pharisees, hypocrites! because ye build the tombs of the prophets, and garnish the sepulchres of the righteous, And say, If we had been in the days of our fathers, we would not have been partakers with them in the blood of the prophets. Wherefore ye be witnesses unto yourselves, that ye are the children of them which killed the prophets. Fill ye up then the measure of your fathers. Ye serpents, ye generation of vipers, how can ye escape the damnation of hell? Wherefore, behold, I send unto you prophets, and wise men, and scribes: and some of them ye shall kill and crucify; and some of them shall ye scourge in your synagogues, and persecute them from city to city: That upon you may come all the righteous blood shed upon the earth, from the blood of righteous Abel unto the blood of Zacharias son of Barachias, whom ye slew between the temple and the altar. Verily I say unto you, All these things shall come upon this generation.”
Did you hear the words of Jesus speaking to the Pharisees 'Upon You', 'Upon This Generation'
Jesus was very specific on who would receive Gods judgement by using 'you' and 'this generation'. Jesus was not referring to a future Jewish generation some 2000+ years away.
This climatic judgement occurred by AD 70 when Rome's armies entered Judea and surrounded Jerusalem destroying the holy city and the Jewish temple not leaving one stone upon another.
“For these be the days of vengeance, that all things which are written may be fulfilled.”
Luke 21:22 (All things which are written may be fulfilled)
The celestial signs are apocalyptic language used many times in the OT..... Isaiah 5:30; 13:9-11; Ezekiel 30:18; 33:7-8; Amos 8:9; Zephaniah 1:14-15 etc etc.....
The Jews of Jesus day would have understood that these verses were symbolic or figurative phrases of coming judgement upon a nation and especially in regards to Jesus contemporaries (within that 1st century generation of Jews).
This judgement is done past history and It Will Never Be Repeated.....
“For then shall be great tribulation, such as was not since the beginning of the world to this time, no, nor ever shall be.”
Matthew 24:21 (Daniel 12:1-3).