Arrow of Apollo
A great hunting arrow, and a symbol of Apollo, Lord of Kobol.
Legend states that the Arrow is the one surviving clue to location of the planet Earth (Kobol's Last Gleaming, Part II). According to accounts of the scriptures of Pythia and Laura Roslin's statement to the Quorum of Twelve, the arrow is a key of sorts, which will open the Tomb of Athena. (Fragged)
This arrow itself, or an accurate facsimile thereof, was on display in the Museum of the Colonial Arts in the City of Delphi on Caprica (Kobol's Last Gleaming, Part II).
While the city itself suffered extensive damage as a result of bombing during the Cylon attack, the Arrow itself survived undamaged. It becomes the focal point of Laura Roslin's attempts to discover the whereabouts of Earth following the apparently accidental discovery of Kobol by the Colonial fleet (Kobol's Last Gleaming, Part I. These attempts lead to Lieutenant Kara Thrace disobeying orders and taking a captured Cylon Raider to Caprica, when the Raider is required in a plan to rescue personnel from the Galactica who have been shot down by Cylons over Kobol (Kobol's Last Gleaming, Part I).
It was housed in the Delphi Museum of the Colonies until collected by Starbuck and taken to the Astral Queen and Laura Roslin (Home, Part I).
Once the Tomb was found, Starbuck placed the Arrow in the bow of the statue icon of Sagittaron inside the Tomb. (Home, Part II). Immediately all those in the Tomb found themselves in a grassy field at nighttime surrounded by twelve large stone stabs not unlike those of Stonehenge, ostensibly immersed in some sort of holgram. On each column were the ancient symbol of each Colony as used on their respective old Colonial flags, supposedly before the Articles of Colonization. Roslin noted that the symbols were used back when the ancient names of the Colonies were used: Aries and not Arilon, Taurus and not Tauron, Gemini instead of Gememon, etc.
Above the group, the night sky showed a representation of the same symbol in the form of its constellation as it would be seen on Earth. In fact, Starbuck realized that, according to the Scriptures, that they were all standing on a representation of Earth, seeing what their comrades on Earth would see. The map information would be incomplete without one more stellar reference point found by Apollo in the Sagittarius constellation: the Lagoon Nebula, an object visible on Earth and known as well to the Twelve Colonies. Lee Adama deduced that as they approached this point, the ship would be able to further define their position to Earth. Commander Adama noted that the nebula was "a long way away from here."
The group was not shown leaving the hologram. It can presumed that the group walked beyond the stones and the image faded to their actual location in the Tomb. It is not indicated whether the Arrow was recovered from the Tomb after its use.
Notes
Adama notes that the Lagoon Nebula was known to the Colonials by the astronomical classification of M8. This is identical to what we call the object here according to the official name from the International Astronomical Union.
The nebula, in reality, appears a a gray object in the sky with binoculars or telescope. It would not be as vivid or large in the sky by the naked eye as it was shown in the group's vision. The object was in the proper constellation of Sagittarius.