Even more important is that English "going to" has various uses.
I mean the following sentences look absolutely different to me, and only 1st could be translated with "собираться", whereas 2nd is "pure future" in Russian.
I am going to visit Russia next year. В следующем году я собираюсь съездить в Россию.
I am going to store in a hour. Я пойду в магазин через час.
Since 3min15sec:
Вулкан - Смотреть Южный Парк - Южный Парк онлайн