Basis of Drishti

Lord Brahma taught Rashi Drishti in circle.
Here is how to see:
(1) Draw a circle.
(2) mark point 1 at 15 degree left to verticle diameter.
(3) mark point 2 at 15 degree right to verticle diameter.
(4) point 1 and 2 will be at the top of circle separated by 30 deg.
These are signs Ar and Ta. Similarly continue to mark all signs at 30deg.
(5) Now as per BPHS,1,2 are in East,3 in SE,4,5 in South,6 in SW,7,8 in West,9 in NW,10,11 in North,12 in NE. These are seen clearly in above construction.
(6) Join 3-9 diameter. Draw 2 parallel lines on both sides of it.So 2-10,1-11,4-8,5-7 are joined.
(7) Similarly repeat with 6-12 diameter to get 5-1,4-2,7-11,8-10.
(8) East can see west and North can see South.
So join them to get12-9,1-8,2-7,3-6 and 3-12,4-11,5-10,6-9.
Now your Rashi-Drishti-Chakr is ready. You can see that each sign isjoined with 3 signs on which it has Rashi-Drishti. Thus Rashi Drishti is due to placement of signs in the sky in specific position.
Example: Consider a person(planet) standing on ground he can see something.Now if he is standing on hill,he will see something else.The person is same but his view has changed due to placement. This is Rashi Drishti.

Now consider a kid and a person. a kid being small,can see only a few things but the person being taller can see more. This is why inferior planets(Sun,Moon,Mercury,Venus) have only 7th aspect while superior planets(Mars,Jupiter,Shani,Rahu,Ketu)have additional aspects. Depending on their duties, they are placed in suitable orbits/inclinations so that they can see houses of their interest. Mars is commander so he has to protect Land(4th)and fight wars(8th). Guru(minister) gives Advice(5th) and tells Dharm(9th).Shani being servent, he has to do work(10th) assigned by boss and communication(3rd). Thus you can see Grah Drishti.

Now a person may see different somethings at different times at same place.eg. Some members read mails of specific persons only even though all mails are there on list.Some members are interested only in reply to their mails. So this will depend on thinking of person. This is seen in NakshatrDrishti.

Benefic/Malefic aspect gives good/bad results.
Different planets have drishti on different Nakshatr.
15th is common.Sun-14,15 Moon-14,15 Mars-1,3,7,8,15 Mercury-1,15
Jupiter-10,15,19 Venus-1,15 Saturn-3,5,15,19
Nakshatr also aspect other nakshatr like Rashi. This is seen in Sarvatobhadr chakr.
I will explain a short method for this.
(1) Draw 9 vertical and 9 horizontal lines.
(2) Ignoring the 4 corners of square,write krittika in top left.
(3) Continue from krittika in clockwise direction and write names ofall Nakshatr including Abhijeet after Uttarashadha.
(4) Nakshatr connected by straight line aspect each other.
This is also called SAPT-SHALAKA-CHAKR. It is used in Muhurtas.
Malefics should not aspect important Nakshatras at the time of Muhurt.
Since all drishties are mutually independent and work togather,they can be considered in all cases. Since BPHS uses only Rashi and Bhav,Drishties based on Nakshatr are not used for interpretation in this book.
Food for thought: A kid can sit on shoulder of person and see morethings.
So when two or more planets are togather,will they aspect more?