I'm confused about legendarys in GO

I've heard you have to catch them in raid battles, but only for a limited time. Is this true? I've seen regular raid battles, and before it starts the pokemon is in the egg. Does the egg have to be a certain color?

Right now you can get Articuno and Mew in research tasks and Ho-oh out of legendary eggs. You can also catch Mewtwo if you have an Ex-raid pass.

No other legendaries can be found.

Legendaries hatch out of silver eggs, the egg spawns and countdowns for 45 minutes then hatches. Once it hatches you have 45 minutes to start battling it. You need multiple people to faint it. Like over 8. Then you get 9-14 or so Premier balls to catch it if you win, if you use all of them then it flees and you can't catch it. If its shiny then it has a 100% catch rate as long as it goes in the ball.

Thank you for this because honestly I was confused too.

I play super casually because of where I live.. not much happens. lol

I probably will never gather enough friends to pull off an egg raid. Haven't managed to yet. Booo..

I just did my first raid today.
I opened Go at my work desk and saw one was starting down the road and it was Kyogre, I was happily suprised to see 8 other players already there taking their lunch break once I got there.

We beat it but sadly I didnt get the catch :-(

However on my way there I did get a 1500+ CP Feraligatr