and said that the Avesta was kept there. Henning believed that Ibn-al Balkhi meant the very Ka'ba-ye Zartosht. To disprove this view, it can be said that the chamber of Ka'ba-ye Zartosht is too small to keep the Avesta and other religious books and royal flags; a wider and larger site was necessary for such an intention. Also it can not be accepted that a place that far from the palaces would have been preferred to the large and various palaces of the Achaemenid shahanshahs and official and governmental buildings for keeping the Avesta and royal flags. Since there is another tower like Ka'ba-ye Zartosht in Pasargadae titled "Solomon's Prison", it can not be accepted that the Achaemenid shahs changed the site of the Avesta or the flags. By the way, if those who believe Ka'ba-ye Zartosht to be the place of the Avesta citing Ibn-al Balkhi's Fars-Nameh, look at the writing of the same book a little prior to the word "Kuh-Nefesht", it is written: "...afterwards, he accepted him; and he had brought the book of Zand for wisdom and had tanned twelve thousand pieces of cow skin and written on; he accepted it for gold and "shatasef"; and there is a mountain in Persian Istakhr called Kuh-Nefesht." Thus, it is not possible that a book written on the skin of twelve thousand cows fit in the chamber of Ka'ba-ye Zartosht. Side view In the recent years, Reza Moradi Ghiasabadi has presented a new interpretation of the structure by doing field research and considers it an observatory and a solar calendar and believes that the blind windows, the stairs opposite the entrance door and the construct have been a timer or a solar index for measuring the rotation of the sun and subsequently keeping the record of the year and counting the years and extracting calendars and detecting the first days of each solar month and summer and winter solstices and spring and fall equinoxes. He concludes that the beginning of each solar month could be detected by observing the shadows formed on the blind windows. However, this theory can not be completely true; and one of the reasons that can be stated to refute the theory is that the direction of the geographic North of each region could be different from the direction of the magnetic North. The orbital inclination of the magnetic North from the geographic North