It wasn't R. Akiva that detained the witnesses, but rather Shazfar, magistrate of Gader.

R. Gamliel responded by removing him from his position.

A father and son who saw the moon should both go to Beis Din.

Even though they can't testify together, if one is invalidated, the other can join another person's testimony.

(R. Shimon): All relatives can combine for testimony about the moon.

(R. Yosi): Tuvia, his son and his freed servant went to testify about the moon;

The Kohanim accepted him and his son;

Beis Din accepted him and his servant.

R. Shimon's reason is that Hash-m gave over the mitzvah of sanctifying Rosh Chodesh to Moshe and Aharon, who were brothers.

The others explain it just to mean that the responsibility of handling the testimony was given to the leaders of the generation.

(R. Chanan bar Rava): The Halachah follows R. Shimon.

(R. Huna): How can you go against the cited story in the Mishnah?

(R. Chanan bar Rava): I said this many times to Rav and he didn't object!

(R. Huna): This was because you learned the opposite positions; that R. Shimon disqualifies certain combinations.

(Citing Shmuel): The Halachah follows R. Shimon.

The following people are disqualified from giving testimony:

Gamblers,

Those who lend on interest,

Pigeon racers,

Those who trade in Shemitah produce,

Servants.

The rule is that any testimony for which a woman is invalid, these are also invalid.

From the Mishnah we see that if women are valid for certain testimony, so are these people.

(R. Ashi): Thus, a thief according to Rabbinical law is valid to give testimony that a woman could give.

If a witness is unable to walk, we put him on a donkey (even on Shabbos) or stretcher.

Witnesses can take sticks for self-defense.

They can also take provisions if the journey will be long (a day's journey may be taken and Shabbos transgressed).

If Beis Din don't know a witness, a character witness is sent with him.

Originally, all people were accepted as witnesses;

After the Baytusim sabotaged the process, it was decreed that only recognized people would be accepted.

Question: How many people would be required as character witnesses?

Answer: One

Question: Surely one alone is not believed; we see in an anecdote that more came!?

Answer (R. Papa): It means that one pair is required.

This is also clear from the Mishnah referring to the witness not being recognized by Beis Din.

It must be referring to a pair of witnesses, as two are required.

So, too, the character witnesses being referred to are a pair.

Question: Surely only one character witness is required, as we find that R. Nehorai accomplished it!

Answer: R. Nehorai was accompanied by another witness, who was not mentioned out of respect for R. Nehorai.

Alternate answer (R. Ashi): R. Nehorai was going to join up with another witness.

Question: If so, what is the Chidush?

Answer: We might have thought that because of the risk that he may not be able to find him, he may not break Shabbos.

Ulla attested that Rosh Chodesh had been declared in Eretz Yisrael.

(R. Kahana): Even a lesser person than Ulla would be believed.

The reason is that people wouldn't lie about something that is due to be discovered by everyone.

A Beraisa likewise states that even a witness from the other side of the world is believed to attest that Beis Din sanctified Rosh Chodesh.

The Baytusim (who wanted the Omer to begin on Sunday) once hired false witnesses to deceive Beis Din about the moon.

One of them was on our side, and told Beis Din (by way of metaphor) that he had been hired to trick them.

Beis Din awarded him the money that he had been paid and gave Malkus to the Baytusim.

From that time, it was decreed that only people recognized as non-Baytusim would be accepted for testimony.

Originally, there was a relay of fires to transmit the message about Rosh Chodesh.

When the Kusim sabotaged the process, they sent messengers instead.

The fire signals were made from wood and flax, and were waved from atop a mountain until the person on the next mountain did the same.

The message was thereby relayed from Har ha'Mishchah to Beis Baltin, where the Diaspora could see it lit up like a bonfire.

We see from a Pasuk that the Masu'os spoken of in the Mishnah are fires.

(Beraisa): The fire signals were done only for new moons that appeared on time, and they were done on the eve of the 30th day.

Question: Why were they only done for abridged months?

Answer (R. Zeira): As a Gezerah in case of the end of an abridged month which fell on a Friday, when the fire can only be lit on Motzai Shabbos:

If fires are lit for both types of month, people won't know if a fire on Motzai Shabbos is being lit on time for a full month or if it was an abridged month and it was delayed because of Shabbos.

Question: Let fires be lit for both months, and when Rosh Chodesh is on Friday, let no fire be lit (and people will work out that it must be an abridged month)!?

Answer: People will consider that it might be a full month and something prevented them from lighting a fire.

Question: Let fires be lit only for full months?

Answer (Abaye): It would result in two days' loss of work, as people don't know when Rosh Chodesh is until the second day.