Abstract
This article discusses four Luminous Blue Variables (LBVs): η Car, AG Car, HR Car in the Milky Way and S Dor in the LMC. LBVs are difficult stars to understand because of their sudden eruptions. Time scales for these “great eruptions” are uncertain, possibly hundreds to thousands of years. Historical data onsome of these stars from the AID International Database have been analysed using the AAVSO Vstar program, with the date-compensated discrete Fourier transformation (DCDFT) and with the CLEANest algorithm. The results show that there are multiple periods in the range of ten to thirty years, in addition to the much longer time scales of the significant eruptions, which are beyond the scope of this research.