Rahu and Ketu, the two Lunar Nodes have been a constant center of controversy from the earliest of days - whether in Vedic, Arabic or Christian astrology and astronomy. The important fact is that eclipses are associated with these geometric points instigating human curiosity on eclipses and what the consequences of an eclipse are.
I do not consider myself a professional astrologer, but this is what I have observed on influences of Rahu the Lunar Upper Node especially during eclipses. Ketu the lower node is hard to determine, therefore I will stick with the head - forgive the pun.
My two cents on Rahu - Rahu reverts. Rahu is a key factor that repeats history. It is funny yet not a laughing matter; if you were to make a resolution a few weeks or a month before an eclipse or where Rahu would influence the two luminaries - Sun and Moon, your resolution may fail, you would simply revert back to where you started.
The two geometric points are in a constant retrogression (traveling in the opposite direction from the rest of the heavenly bodies); perhaps that was the reason the two geometric points were given so much importance throughout history.
The reversal, the tendency to remain status-quo; to revert is predominant among these points.
A woman may have a miscarriage around an eclipse because of the 'nodes reversal factor' sending her back to the state the child was not conceived.
A lost item may be found, the reversal being it was never lost in the first place.
Saturn may slow you down; rarely does the influence of a heavenly body begin a reversal, unlike the Lunar Nodes that decelerate to the extent you revert to an earlier stage.
Again my 2'cs - do not make a resolution when a eclipse is around; if you want to quit smoking or a habit, wait till the eclipse is over. If you are under a Dasa or a Antardasa / Bhukti of Rahu or Ketu; maintain a status-quo, these are not times for change. Wait till a period of Sun, Mars, Saturn foster the change in a period unblemished by the two nodes.
Classical astrology Vedic, Arabic, Ptolemy have virtually treated these moving points as heavenly bodies. The perception that Rahu is an impersonator of the Graha or Planet it is associated with can be taken with a pinch of salt. I have not seen how it works and have not received an explanation either on its beneficence or otherwise.
Some state that like the planets, Rahu and Ketu are dignified when they occupy a sign. Till date, different schools of astrology have associated Rahu's exaltation with either Venus' or Mercury's sign. I think the house of exaltation - Taurus, Gemini or Virgo has remained an astrological challenge till date.