A small minority of western astrologers have since followed Fagan and used a sidereal system as in Indian tradition. The Indian tradition also uses 12 equal-sized signs; the distinction is in where the signs start. Berg breaks from historical tradition to combine sidereal astrology with the IAU's official constellation boundaries defined in 1930, creating a 13-sign system. This results in astrological signs that correspond directly to the time the Sun spends in their eponymous constellations. For example, the Sun spends forty-five days in Virgo and only six days in Scorpio. The 13th sign is Ophiuchus, where the Sun passes during the first two weeks of December.