I have always been curious and try to find a logical answer for many of our age old practices.
Why are the deities in our temples face either East or West most of the time (there are exceptions where the Deity faces the North but they are few and far between)? - For finding the answer one may have to go to an era where there were no electric lights and even possibly no fire. The idols were normally inside caves or other covered places. The worship was done during early morning and late evening , before and after the agricultural activities. Since there was no electricity, life began and ended with sunrise and sunset. Morning sun and evening sun are low in the horizon and their rays directly illuminated the deity depending on which side the deity faced. This became a practice and convention later on.
The same logic is applicable to lighting the camphour at the end of a pooja. Camphour gives sufficient illumination for the devotees to see the deity clearly, albeit briefly and they would indeed like to see the deity's face once the 'archana' has been done. And of course, the temple lamps or diya are lit for illumination purpose too.
You might ask 'What about incense sticks?' or Agarbathi as they are popularly known. The sanctum sanctorium has little ventilation and is closed for most of the day resulting in air becoming stale. Burning incense sticks smokes away some of the flies and germs apart from giving a sweet fragrance which is quite welcome.
Our forefathers were very wise. There was always a solid reason for all of their actions. Only thing is that we have not cared to ask 'Why?'
