Science Fiction & Fantasy Stack Exchange is a question and answer site for science fiction and fantasy enthusiasts. It only takes a minute to sign up.
Sign up to join this community
The Jedi could feel on what's happening about them. Like a disturbance in the force. This question is somewhat similar to Why couldn't the Jedi detect Senator Palpatine as having powers?
But prior to Attack of the Clones, Dooku is already a Sith Lord called Darth Tyranus. And at the beginning of the film, The Jedi only viewed Dooku as a political idealist. Bottom line question is why the Jedi didn't sense Dooku is already a Sith Lord at that point of the very beginning of the film?
Palpatine could have used the same power that he used to shield his own identity from the Jedi.
The answers to the question "Why couldn't the Jedi detect Senator Palpatine as having powers?" describe this power as "Force Stealth".
It helped that the Jedi Order was dramatically overconfident. At one point in The Attack Of The Clones, Padme Amidala shares her suspicions of Count Dooku with the Jedi. Mace Windu responds with:
You know, milady, Count Dooku was once a Jedi. He couldn't assassinate anyone. It's not in his character.
As a member of the council, and a leader in the Jedi Order, Mace Windu's judgement would have been respected by all Jedi. Even if some disagreed, they wouldn't have had enough evidence to directly challenge him.
Based only on the films, I think they became too confident, and that was their collective flaw. The Jedi council were under the assumption that the Sith were extinguished for a long time (Ep I), and I also that think because the Sith were laying low for so long, maybe that impaired the Jedi ability to sense them. The Jedi council also follow dogma moreso than the will of the force, whereas Qui-Gon, whom they didn't allow on the council and was said to have been too defiant, (Obi Wan tells him in Ep I that if he would follow the code he would be allowed on the council) seemed to be more in tune with the force...so I don't think it was any coincidence that he found Anikin and he faced Darth Maul.
The Jedi were impeded from perceiving the Sith due to the work started by Darth Plagueis and expanded on by Darth Sidious. You can read a bit about this in the novelization of the Revenge of the Sith, the Rise of Darth Vader and in some of the graphic novels. My own take on this is that the Jedi were the imbalance in the force - taking children away from their families, forbidding marriage (which, would eventually result in removing force sensitives from the gene pool), stifling most conflict etc. The force raised up Anakin Skywalker, conceived directly from the force by the manipulations of Darth Plagueis. In spite of their intentions to the contrary (Plagueis just wanted a better apprentice and Anakin just wanted to save himself from more loss), the force arranged to have the Sith and the Jedi wiped out and start over again.
You have to be physically close to a person to sense Dark Side.
Jedi certainly recognized Dooku as a Dark Side user when they met him on Geonosis. We don't have enough information, but looks like Dooku avoided meeting Jedi since he left the Order and before that encounter. Of course, if someone was very close to person, he could fill Force shift even from affair, but Jedi Order in last days of Republic shunned attachments so Dooku (and other Jedi) didn't have really close friends that could sense what is in their souls even when they are not physically present. Exception could be Yoda and maybe Mace Windu, but this is not elaborated either in Canon or Legends.
As for recognizing someone being a Sith, Force simply doesn't work that way :) Sith were organization with certain traditions and beliefs, but that is about it . Jedi did guess that Dooku is probably a Sith, but they didn't know that he is Tyranus (unit late in the war) and that Tyranus is actually Darth Tyranus.
