How long is each Vastu Devta's time period, and when are Shikhi and Parjanya active?
Each outer devta has a sadhana period of 45 minutes, so the 32 outer devtas complete the 24 hours (32 x 45 minutes) and come back to the same point. Shikhi's period runs up to 3:00 am and Parjanya's from 3:00 to 3:45 am. Havan and offerings made in a devta's own period wake and activate it quickly.
Related questions
Is the time given for each devta only its starting time, or a full period?
It is a 45-minute period. The count starts with Shikhi devta from 3:00 to 3:45 am, and each next devta takes the next 45 minutes.
Does the time of offering matter when worshipping the devtas?
In a full vastu poojan all 45 devtas are worshipped and offered together. When one particular devta has to be activated, offer its bhog samagri or do its jaap in its own time slot for the maximum result. An offering at another time is not useless, but just as food eaten at the fixed time of hunger satisfies more, the result differs.
In which month are Shikhi and Parjanya devtas awake?
Every devta has its own month; Shikhi and Parjanya stay awake in Shravan (Sawan). The coconut kalash can still be placed at Parjanya after Shravan has passed; once Parjanya is awake it fulfils the wishes of the residents, so that in such a house whoever enters and voices a wish sees it fulfilled.
What should be done if the shilanyas (foundation stone) has been laid in the wrong direction?
Fix a fresh auspicious muhurta for shilanyas, dissolve (khandit) the earlier one, and perform it again in the new muhurta. It is dissolved the way an installed kalash is removed: by addressing the devtas who supported the earlier shilanyas with a request about it.
About 11 or 12 of the 45 devtas are asuras. Whose energy should be increased and whose kept low to stay balanced?
This was to be explained in detail later, as there is a big confusion about it. Asura devtas are also needed: the day there are no asuras in your house, your work will not run, so the aim is balance, not removing them.
After placing sweets and later chanting the mantra 27 times at a devta place, I felt strong heat in my body. Why?
It shows a defect or imbalance at that pad. When an offering reaches a defective place the defect tries to come out, as when granite tiles at one devta pad cracked during a group havan, and the body reacts. The uneasiness is a signal: the pad must be purified and activated with the method being taught (havan samagri, bhog samagri, mantra or the samagri to hang), so wait for the full method before trying again.