The wonder or sign of the woman in heaven, Re 12:1-5, appears to be going to take place in the heaven as a astrological conjunction with the sun, planets and the moon and two constellations on Sept. 23, 2017. Actually, two wonders or signs are mentioned in the following verses. The second being the great red dragon.
Revelation 12:1-5 KJVS
 And there appeared a great wonder in heaven; a woman clothed with the sun, and the moon under her feet, and upon her head a crown of twelve stars:  And she being with child cried, travailing in birth, and pained to be delivered.  And there appeared another wonder in heaven; and behold a great red dragon, having seven heads and ten horns, and seven crowns upon his heads.  And his tail drew the third part of the stars of heaven, and did cast them to the earth: and the dragon stood before the woman which was ready to be delivered, for to devour her child as soon as it was born.  And she brought forth a man child, who was to rule all nations with a rod of iron: and her child was caught up unto God, and to his throne.
A short video that covers the high points of the sign of the woman.
A link to a open source astronomy software program, that can be used to verify what is shown on the video, can be downloaded here.
A review and description of the databases used in the software which confirms the reliability and accuracy of the software.
Some theologians and biblical commentators say Re 12:1-5 represent Mary, and that the birth of the man child is the birth of our Lord. And that the great red dragon represents Satan using King Herod to kill the Lord as soon as he was born. Apostle John was given explicit instruction by the Lord on what he should write in the book of Revelation.
Revelation 1:11,19 KJVS
 Saying, I am Alpha and Omega, the first and the last: and, What thou seest, write in a book, and send it unto the seven churches which are in Asia; unto Ephesus, and unto Smyrna, and unto Pergamos, and unto Thyatira, and unto Sardis, and unto Philadelphia, and unto Laodicea.  Write the things which thou hast seen, and the things which are, and the things which shall be hereafter;
It goes against what is written in the above verses, that Re 12:1-5 describes events in the past surrounding our Lord’s birth. John was instructed by the Lord on what he was to write in the book of Revelation. He was to write the things he had seen, things which are, and things which shall be hereafter. John was not old enough to have seen the events which transpired at the time of our Lord’s birth because he was younger than Jesus. Most agree the narrative of the book of Revelation to be linear and that would place the 12th chapter in the future or as the Lord states it, the hereafter. Other theologians and bible commentators think that the woman is Israel, or the church but is not. According to Apostle Paul, who was highly educated as a Pharisee, and inspired by the Holy Spirit to write the bulk of the New Testament epistles, the woman who gives birth to the promise seed is Jerusalem from above or Sion, Gal 4:22-28. Which agrees with Isa 66:6-8 and He 12:22.
Isaiah 66:6-8 KJVS
 A voice of noise from the city, a voice from the temple, a voice of the Lord that rendereth recompence to his enemies.  Before she travailed, she brought forth; before her pain came, she was delivered of a man child.  Who hath heard such a thing? who hath seen such things? Shall the earth be made to bring forth in one day? or shall a nation be born at once? for as soon as Zion travailed, she brought forth her children.
Notice that as soon as Zion travailed she brought forth the children of God, Ro 9:26, the body of Christ. Verse seven closely matches the language used in Rev 12:2, and supports the fact that Rev 12:1-5 is not pointing back in time, but ahead. I recently bought the Stellarium app for my iPad to confirm the information in the videos which I linked to at the beginning of this article. From my investigations using that software, the wonder or sign of the woman as described in Re 12:1, will appear in the sky on Sept. 23, 2017. What is commonly known as the rapture, is associated with the sign of the woman, Re 12:1-5, and the woman’s birth of the man child. If so, then the rapture or gathering of the saints unto the Lord, takes place at the sounding of the seventh trumpet. I base this conclusion largely on Re 10:7 and Re 11:15
Revelation 10:7 | ESV
7 but that in the days of the trumpet call to be sounded by the seventh angel, the mystery of God would be fulfilled, just as he announced to his servants the prophets.
Re 10:7 refers to when the actual event takes place a short time later in the book of Revelation.
Re 11:15 And the seventh messenger trumpets. And loud voices occurred in heaven, saying, “The kingdom of this world became our Lord’s and His Christ’s, and He shall be reigning for the eons of the eons! Amen!”CLV
The mystery of God is Christ in you the hope of glory, Col 1:26&27, and that mystery will be finished, completed when the seventh angel sounds. Because at that point in time the body of Christ will join the head, Jesus Christ, and become His Christ. The large portion of YouTube videos that delve into the Revelation 12 sign, link this sign to a pre tribulation rapture. They present the book of Revelation as not being chronological, but with chapters or parts of chapters that they call parenthetical, which they claim overlap earlier chapters in the narrative. They have constructed timelines, charts and all this is based on their intensive study of the book of Revelation. With this theory, they place the 12th chapter of Revelation at the beginning of the tribulation. Thereby justifying a pre tribulation rapture. If one reads the definition of parenthesis you will see that the literary device is limited in scope. A online definition of Parenthesis as a literary device-“Parenthesis is a stylistic device that comes from a Greek word, meaning to place or alongside. Parenthesis is a qualifying or explanatory sentence, clause or word that writers insert into a paragraph or passage.” I did some study on the verses in the book of Revelation and came up with verses that disproved, in my mind, their claims regarding the wonder or sign of the woman of Re 12:1-5, being the pre tribulation rapture of the church. I covered Re 10:7 above, which to me is very persuasive at setting the rapture of the body of Christ at the sounding of the seventh trumpet. Additionally Re 8:13 presents a linear series of events, connected to three trumpet and three woes, that make the narrative of the 8th to 12th chapters of Revelation linear in regards to chronology.
Revelation 8:13 KJVS
 And I beheld, and heard an angel flying through the midst of heaven, saying with a loud voice, Woe, woe, woe, to the inhabiters of the earth by reason of the other voices of the trumpet of the three angels, which are yet to sound!
Let’s look at where these three woes occur in the narrative of the book of Revelation.
Revelation 9:11-12 KJVS
 And they had a king over them, which is the angel of the bottomless pit, whose name in the Hebrew tongue is Abaddon, but in the Greek tongue hath his name Apollyon.  One woe is past; and , behold, there come two woes more hereafter.
Revelation 11:13-14 KJVS
 And the same hour was there a great earthquake, and the tenth part of the city fell, and in the earthquake were slain of men seven thousand: and the remnant were affrighted, and gave glory to the God of heaven.  The second woe is past; and , behold, the third woe cometh quickly.
Revelation 12:12 KJVS
 Therefore rejoice, ye heavens, and ye that dwell in them. Woe to the inhabiters of the earth and of the sea! for the devil is come down unto you, having great wrath, because he knoweth that he hath but a short time.
There is a continuation of a theme of the three woes which occur with the last three Trumpets that sound, 5-7, that unfolds in a linear fashion from the 8th, though the 9th, 11th and 12th chapters. So to be honest I can’t see how this theory makes sense based on scripture. In order for the wonder or sign of the woman, Re 12:1-5, to be at the beginning of the tribulation, there would have to be a 3 1/2 year passage of time between Re 12:5 and Re 12:12But at this juncture of time, middle of March, I am concerned that a mid Tribulation rapture taking place about six months from now appears unlikely. But the conjunction of the moon, Jupiter, sun and the three wandering stars that are planets with Virgo and Leo on 9/23/2017 matches the description given in Re 12:1&2 so exact, it is hard to dismiss. But on the other hand the lack of two witnesses giving their testimony in Jerusalem is also troubling. I guess it is a matter of wait and see. A couple nights ago I was playing around with the Stellarium app. I input the Sept. 23: 2017 date, and added the simulated land that forms the horizon and the sign of the woman was below the horizon in my location at that time of night. So I thought to try viewing the constellations from a different location. And then I thought, why not Israel. So I chose for the location Jerusalem in Israel, and was surprised it was one of the stored locations in the program. I looked for the Virgo constellation and panned the view around a bit, and due east came into view. The sun is just below the horizon illuminating the head of Virgo. In the app you can add or remove the simple drawn image representations of the various constellations which appear over the stars of the constellations. And the constellation Leo the lion, with the 12 crowning stars was clearly visible above her head, just at dawn. Right at due east. Of course Venus is known as the day star and is one of the planets that completes the crown of 12 stars. Fittingly enough the brightest of all the stars in the twelve star crown. The time when I saw this was around 22 07 10, in the time field setting in the software. Two scriptures came to mind, so I looked them up with my bible app. I felt the Spirit of the Lord move on me as I read them.
Matthew 24:27 KJVS
 For as the lightning cometh out of the east, and shineth even unto the west; so shall also the coming of the Son of man be.
2 Peter 1:19 KJVS
 We have also a more sure word of prophecy; whereunto ye do well that ye take heed, as unto a light that shineth in a dark place, until the day dawn, and the day star arise in your hearts:
It occurs to me that scriptures in Daniel may be relevant on the recent ability of being able to predict this future sign in the heavens taking place on a specific date using astronomy software. Which of course was impossible before computers were invented.
Daniel 12:2-4 KJVS
 And many of them that sleep in the dust of the earth shall awake, some to everlasting life, and some to shame and everlasting contempt.  And they that be wise shall shine as the brightness of the firmament; and they that turn many to righteousness as the stars for ever and ever.  But thou, O Daniel, shut up the words, and seal the book, even to the time of the end: many shall run to and fro, and knowledge shall be increased.
It is only with the increase of knowledge in computers and software technologies, that this particular alignment of planets, the sun and moon in conjunction with the two constellations was discovered. This sign may speak of troubling and chaotic times ahead. Since great suffering is on the horizon for the seed of the woman. I think it is fitting that this website’s main subject matter, is the role suffering plays in being conformed to the image of Christ.