Celebrimbor and Sauron: how did he notice?

[Iarhen]

We all know that when Sauron created the One Ring, wore it and pronounced the spell to dominate the other bearers, Celebrimbor knew who Annatar was and his plans.

But how did Celebrimbor knew? Was he wearing one of the elven rings and did that ring gave him foresight inside Sauron's mind?

How was it possible for Celebrimbor to know who Annatar was? How did he knew his true identity? And, most importantly, how did Celebrimbor found out Sauron's plans concerning the rings?

And a final question. It is said that the elven rings were never used openly, and never wore, when Sauron had on his Ring. Why? Would the elven rings be transformed as the other 16 rings were?

[Gwaihir the Windlord]

While he wore the One Ring he could percieve all the things that were done by means of the lesser rings, and he could see and govern the very thoughts of those that wore them.
But the Elves were not so lightly to be caught. As soon as Sauron set the One Ring upon his finger they were aware of him; and they knew him, and percieved that he would be master of them, and of all that they wrought. Then in fear and anger they took off their rings.

The One Ring opened a connection with the other nineteen instantly. Through this Sauron could control the other Rings, and lay bare the minds of their wearers, but in the same instant he was himself percieved by the Elves - who realised his purposes and what was happening, whether or not they yet knew truly who he was. Obviously Sauron hadn't quite expected that to happen.

Taking off their rings in that instant, when the fought initially gainst the will of Sauron and were not yet whelmed by it, they escaped. Had any Elf tried to put on a ring, one of the Three, again while Sauron was in control of the One, then they would have fallen under his domination as did the Nazgul afterwards.