A critique on the theory of determining the first day of the seasons at Niasser fire-temple
Chahar-taqies are buildings from ancient Iran. Although not for sure, many believe that these buildings were pre-Islamic religious buildings in Iran. Niasser fire-temple is one of the examples of constructions that are in good condition in the Niaser Mountains of Kashan. Reza Moradi Ghiasabadi, a freelance researcher, has done extensive research on Iranian Chahar-taqies, including the Niasser fire-temple. He believes that the angles and positioning of the Niasser fire-temple structure are such that the sunrise on the first day of each season is consistent with certain axes of the building. Therefore, it can be used to determine the beginning of each season. He has expressed his theory in two books on “The calendar buildings” and “Calenddric Structure of Iran” about the Niasser fire-temple. In this study, by calculations, measurements and field observations as well as defining the ortive amplitude parameter, we show that the sunrise along the beginning of each season does not match the axes of the building. Because in the equinox, that is the first day of spring and fall, the sun does not rise from any specific angle. In addition, the proposed theory has not paid attention to the first day of summer and the first day of winter. On the first day of spring and the first day of autumn, the sun rises from exactly east, which does not match any of the axes of the building. The difference in sunrise azimuth every day of the year from the east azimuth is called the ortive amplitude. The ortive amplitude depends on the latitude of the observer as well as the angle of declination of the sun every day of the year. The latitude of the Niassar fire-temple is about 34 degrees. Hence, the ortive amplitude is about 29 degrees. That is, on the first day of summer the sun rises on azimuth about 61 degrees. On the first day of winter, the sun rises on azimuth about 119 degrees. Declination of the sun in the days before and after the solstices is very small. Therefore, the measurement of the ortive amplitude in the solstices must be very precise. But the columns in Niasser fire-temple does not have that precision. In other words, for about a month, the sun appears to rise from one point. Hence, we can not use the Niasser fire-temple to specify the first day of summer and the first day of autumn. We conclude that the theory presented in solstices, namely the first day of summer and the first day of winter, is also inaccurate.
Keywords: Chahar-taqi, Fire-temple, Astronomy, Ortive amplitude
Presented by Safaei, Iraj; in the "Journal of Maremat & Me’mari-e Iran", Vol 11 No.26 Summer 2021.