Surya is a god. How can it sit in the outer paishachik zone?
When the rays of the Sun come, they fall outside first and only then come inside. The devtas of the outer ring sit there for protection: they occupy the land on all four sides so that no negativity can enter.
Related questions
Are there 45 vastu devtas or 49?
There are 45 devtas, but 4 more devtas stand on all four sides to protect them, so basically there are 49. Bhog samagri is offered to these 4 guardians as well, after the 45.
How far does the influence of a devta reach beyond its own pad?
As in a kundli, where Jupiter blesses whatever it aspects with full drishti, a devta also aspects the devta opposite it; Surya, for example, balances Varun. If you cannot balance a devta directly, balance the devta whose full drishti falls on it, and its gaze will set it right.
I learned elsewhere that in 81 pad vastu the East falls between E4 and E5. Is that right?
No. In 81 pad vastu exact East falls on E5 (Surya); East between E4 and E5 belongs to the 64 pad grid, so correct it. The reference is in Vishwakarma Prakash, with the page number given in the previous class; the Hindi translation from Sanskrit by Krishna Kumar Jugnu of Udaipur and the edition of Maharshi Abhay Katyayan give the same.
In which direction exactly should the picture for Shikhi or Parjanya be put?
A devta does not own one wall; it is an 11.25-degree sector. Shikhi and Parjanya face East, so put the picture within that sector, facing East; when a student asked, West-facing was also accepted.
Shikhi lies in the pishach bhoomi, so where should one sit for its jaap?
One cannot sit in the pishach bhoomi itself. Sit facing East in padmasan or sukhasan, project your vision to the devta's place as if through a telescope and visualise it, and chant the Shikhi mantra on a silver or gold mala, as many rounds as possible, in the period up to 3:00 am; with aahuti the mantra ends in swaha. It helps when the mind is blocked, business ideas do not come or children cannot memorise. Exact words: refer to the class recording.
The North-East is the most sacred direction, so why should the main door not be opened at E1, the pada of Shikhi devta?
Because it is the most sacred and pure place, entering there with shoes and slippers is a serious problem. Shikhi devta, who sits at E1, then produces his fire, and his anger brings agni bhay (fear of fire), a greater chance of fire breaking out in the house. So E1 should not be used for the main door, even though people commonly praise it.