While eclipses are considered to be dangerous times wherein most temples are kept closed and various kinds of sutaka are followed, it is also an ideal time for sadhana and attaining siddhi. The sandhya bhasa of Tantric texts – twilight language – refer to fantastic number of japas to be performed for a mantra or ritual of a deityi in order to energize it. To the laity this may seem impossible or absurd but to those initiated into the path, these are often taken as subtle pointers indicating that the specific ritual or sadhana must be done during an eclipse. While a solar eclipse is the most powerful time, lunar is right next to it in terms of potency.
Most sadhakas, specially Shaktas, ensure that they can perform dedicated sadhana during the time of the eclipse. Any ritual or japa or meditation done during an eclipse amplifies the effects of the sadhana manyfold.
It is also believed that the war of Kurukshetra where the Gita was given to Arjuna become so legendary and is still remembered after so many thousands of years is because there were a couple of eclipses closeby within that span of 18 days. Of course a time so powerful can have its negative effects too. Hence various dos and don’t are traditionally followed during such times.