AngularJS and an external API - getting it to work

I've been trying to access the sqwiggle API inside my Angular app and was testing it using Postman. All seems to work fine. I define a Basic Auth header, do a GET request to the messages endpoint and I get a nice response. These are the request headers (from Postman):

Request URL:https://api.sqwiggle.com/messages
Request Method:GET
Status Code:200 OK
Request Headersview source
Accept:*/*
Accept-Encoding:gzip,deflate,sdch
Accept-Language:en-US,en;q=0.8,nl;q=0.6
Authorization:Basic [secret]
Cache-Control:no-cache
Connection:keep-alive
Host:api.sqwiggle.com
User-Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.70 Safari/537.36

Now in my AngularJS app, I want to do the same:

$http.get('https://api.sqwiggle.com/messages', {
    headers: {
        Authorization: 'Basic [secret]'
    }
}).success(function(e) {
    alert(e);
});

But this results in the following request headers:

Request URL:https://api.sqwiggle.com/messages
Request Method:OPTIONS
Status Code:404 Not Found
Request Headersview source
Accept:*/*
Accept-Encoding:gzip,deflate,sdch
Accept-Language:en-US,en;q=0.8,nl;q=0.6
Access-Control-Request-Headers:accept, authorization
Access-Control-Request-Method:GET
Connection:keep-alive
Host:api.sqwiggle.com
Origin:http://localhost:8888
Referer:http://localhost:8888/
User-Agent:Mozilla/5.0 (iPhone; CPU iPhone OS 7_0 like Mac OS X; en-us) AppleWebKit/537.51.1 (KHTML, like Gecko) Version/7.0 Mobile/11A465 Safari/9537.53

Given the fact that Postman uses JS to get the data from the API, it should be possible in AngularJS too, or am I missing something here? Why is Angular transforming the GET in an OPTIONS request and why is it not adding the Authorization header?

Thanks for your help

Try something like this instead of using $http.get

$http({
    method: "get",
    url: "https://api.sqwiggle.com/messages",
    headers: {
        'Authorization' : 'Basic secret'
    }
}).success(function(data) {
    console.log(data);
});