How Rahu Mahadasa effects according to Astrology?

Let's understand Rahu step by step.

According to Indian Mythology,

Rahu was a Asur(demon) named Svarbhanu. Svarbhanu had done the

worship of the Lord Brahma and He had promised him to give him a

status of planet. In very popular incident of Samudra Manthan ,

Nectar came out and Lord Vishnu took avtaar of Mohini. Mohini gave

nectar to devas and liquor to Asuras. Svarbhanu, somehow knew

something was wrong and he changed his place to Deva's. He was offerd

nectar and when he had just drank it , Sun and Moon yelled that He

was Asura , and he is sitting here. Lord Vishnu immediately cut his

head off. Svarbhanu had already drank the Amrit and now he was

immortal.

Let's see this neutrally.

Among all the Asuras, Svarbhanu was intelligent enough to know that

something was fishy about the distribition of nector. He tricked all

the Devas and also the Lord Vishnu and became immortal.

The head part of Svarbhanu became Rahu and the body part became Ketu.

Later Brahma gave the Snake body to Rahu and Snake head to Ketu.

So if we just take this incident neutrally without any bias.

Rahu has this virtues -

1. Intelligent - He knew that Asuras were being given the Liquor

2. Selfish - He didn't inform other Asuras but he, himself sat in the

line of Devas

3. Can take risk to any extent to achieve something

4. to some extent , controlled - He didnot get lured just by Mohini's

beauty

5. Gets fit anywhere and becomes like the other - He took the roopa

of Devas so perfectly that even other Devas and Mohini could not see

his real form until last moment

6. Hard worker - He had done the Tapascharya and Lord Brahma had

given him the promise that he will be placed with the Grahas.

7. Revengeful - He took the revenge to Sun and Moon even after his

head was cut though Sun and Moon were saved but they have to pass

from Rahu's eclipse every year.

8. In search of power - He wanted to be immortal , He wanted to be

recognized , He wanted to feel privileged.

Let's try to connect it with Science.

Image Courtsey : Google

Rahu and Ketu are actually the areas of two intersections of the

Moon’s orbit around the Earth and the path of the Sun in zodiac.

The ascending node or the node where the moon crosses to the north of

the ecliptic is called the North Node, Rahu. The descending node or

the node where the moon crosses to the south of the ecliptic is

called the South Node,Ketu.

The lunar nodes play an important role in the formation of eclipses.

Eclipses occur when the Sun and the Moon are near the lunar nodes.

What occurs during the Eclipse?

Darkness comes and there is no light. It is the time period of Rahu

where the Sun's rays cannot reach to the Earth.

Sun's light keeps the Earth alive.From Plants to the mammals , all

need it. Very few minutes of Eclipse brings chaos mentally.

During Moon eclipse , Symptoms of lunatics gets increased and these

are times where serial killers also gets activated.

It is the Asura thing. People who have Asuri tendency or Tamo bhava,

It gets increased.

Now let's find about the stability during the Rahu Mahadasha:

Rahu is given the body of Snake and Snake has the walking pattern like this.

It is somewhat similar to roller coaster , To highest peak and to lowest peak , Up and down , Up and down.

Rahu has the Head , It thinks a lot and it wants to go deep into every way possible.

It is said that Rahu takes away everything it gave during its Mahadasha .I think It may be right from one perspective but wrong from the other.

Dasha is the time period of the certain planet who is activated more than the other and depending upon the sign, placement and the house ruled by him. It will give the results.

Now , Let's see by this way - Let's say Mr.X Had Mars Mahadasha and His Mars is activated and it gave the results related to Mars. Mars is related to hardwork,energy , determination and passion.

Now, Rahu time period came. Rahu is all about getting the things, getting the power, following hidden wishes, taking risk to achieve.

in Rahu time period , the person thinks so fast and takes every risk , It comes into state of even gambling to achieve the desired place.

Rahu gives the person passion and a strong hope that he will win.

That's also one way that he is called an illusion.

Let's think Mr.X achieved many things in Rahu Md.

Jupiter comes after Rahu . Jupiter is slow , steady and the planet which don't want the power. It want peace. It want the steadiness. It follows the spiritualism. The person's mindset will be changed.

He will not follow that illusion or the hope that he can actually achieve something. As his eyes have been opened by Jupiter and he came to the reality that everything can not be achieved.

Slowly the person will not work that much , will not risk that much and will not dream that much.

That's the point where people start to loose things.

It is seen in a way that Rahu has taken away things he had given.

Big No ! It is actually , you , Your own thoughts ruled by Jupiter that has changed your mindset.

Rahu should not be blamed for it.

(Obviously the result can be positive or negative depending upon the Native’s Chart, here I am talking only about the gains as mentioned in the question)

This theory may not be totally true but it is not totally wrong as well.

We cannot prevent it because Rahu thinking will not be there in Jupiter time period.

( I am not telling that Jupiter's effect is bad , I am just telling that the madness to achieve is lost with Rahu Mahadasha)