This prophecy is a very curious one that comes from the book of Revelation and appears to come sometime in the middle of the Tribulation.  However, based on astronomical information, that's not possible as there are just slightly over two years between now (when this prophecy was posted) and the occurring of this sign.  As such this event appears to be speaking more of the flight of Israel into the wilderness at the middle point of the Tribulation rather than the actual celestial event that is due to occur on Sept 23rd, 2017.  What the connection is between that event and the fight to Petra is unknown.

In fact, the only thing scholars seem able to agree on is that this is indeed a prophetical sign.  But what it points towards remains to be seen.  It's possible that we, the generation living before the rapture, won't know because it's not meant for us.  As such, only those living at that time will understand its full meaning, which to be honest seems to be the more likely answer as the same thing happened over and over again in times past (ie, the writers and those prior to the time of the fulfillment couldn't understand the prophecy as it wasn't for them) and appears to be repeating itself even today.  So whatever this sign officially points to is not likely to be known until sometime during the Tribulation.

One thing is for certain though.  Scholars do agree that, even though we don't know the full prophetical significance of this sign and prophecy, or even perhaps how it will completely unfold, we do know that it caries with it a dual symbology.  Namely that the nation of Israel gave birth to the Messiah (Jesus) whom Satan tried to destroy immediately after His birth, and that this same nation of Israel will some day be driven into the wilderness, some believe into the rose red city of Petra, where they will be protected for 3 1/2 years during the second half of the Tribulation.