Comparing Matthew 24:29 to events at the crucifixion would indicate that it's literal.
Matthew 27:45
Mark 15:33
Luke 23:44
Now take a look at:
Revelation 8:12
Revelation 9:2
In these passages, the opening of the bottomless pit causes the darkening of the sun. And by application of the fact that the moon reflects sunlight. The moon "would not give her light".
This jives with John 13:30 that says when Judas left the others at the last supper; "it was night". By implication that not only had the sun gone down: but there was very real and thick darkness.
As for the stars falling from the sky?
The gospels speak of "signs" (in the sun, moon and stars) as well as "the sign of the son of man in heaven" (Matthew 24:30)
Jump on over to Daniel 7:13:
I saw in the night visions, and, behold, one like the Son of man came with the clouds of heaven, and came to the Ancient of days, and they brought him near before him.
The event in Matthew 24:30 is picked up in Revelation 5:6. The "lamb as was slain" is standing in heaven. (This happens at the point Jesus dies and his soul (and 2nd Person of the Trinity / Divine nature) ascends to heaven.
This is connected to: "You have not left my soul in hell" and also when he tells the thief "Surely I tell you; today you shall be with me in paradise" This happens right before he says "It is finished".
Which brings us to the next question: When did Jesus "preach to the spirits in prison"?
Connect Passover and the visitation of the angel (at midnight) in Gethsemane to Exodus and the "angel of the Lord" who "passed through Egypt at midnight" and slayed the first born. Jesus is the Passover lamb; but also the "first born from the dead".
Now go back to Matthew 24: "Immediately after the tribulation of those days shall the sun be darkened...." The sun was darkened at noon; but what happened 12 hours earlier? (Jesus, Gethsemane and the angel)
Matthew 24 says the tribulation is cut short or no flesh will be saved. (When is the atonement secured? When are people saved?) The payment / atonement for sin was completed at the cross. Remember "it is finished".
So, what about the stars falling from heaven?
The sun was darkened, the moon did not give her light and the powers of heaven were shaken.
If we look at the end of time; The sun becomes "black as sackcloth of hair". The moon is "blood red" and "the stars fall from heaven". The heavens are "rolled together as a scroll" and "the elements melt with fervent heat". (The cosmos is recreated / raised incorruptible.) The final judgment is here.
Now, back up to the cross. The death of Christ signified judgement upon all those in Him because He atoned for their sin. That was the commencement of Judgement Day; the conclusion of Judgement Day comes at the end of time when all of humanity is resurrected. The redeemed inherit the new heavens and new earth and the unregenerate are cast into the Lake of Fire.
Between ignition event and final event; we're nearing on 2000 years now.
So what happened to the stars at the crucifixion?
Here's my theory:
If Christ hadn't completed the atonement, the end of the world would have commenced at sundown that Friday night. Thus the darkening of the sun, the moon and stars in what we call "outer space" beginning to "come unglued".
Is what we now see of things such as super novas, black holes, etc. the consequence of the commencement of the collapse of the universe that was "stayed" by the completion of the atonement? I don't know because we have no real way of knowing what the night sky actually looked like before the crucifixion. We only know what "science" assumes has always been there. We can believe that is true; but have no way of verifying if it is really so.
So, it seems what was actually literal, which commenced almost 2000 years ago now; will "resume" and be completed at the end of time.