Poll? Vote? Where the hell did the people who wrote this go to school?!
Poll: "a sampling or collection of opinions on a subject, taken from either a selected or a random group of persons, as for the purpose of analysis."
Vote: "express one's preference for a candidate or for a measure or resolution"
If anything, this is a quiz, and one could submit an answer or a guess, but not a vote. Opinion or preference has no value in this case. No amount of voting can affect the answer, as the answer is a fact. Hence there can be no opinion about its validity. The imprecision with which language is used never ceases to amaze and annoy me. No, wait... amaze isn't the correct word...
Maybe the Weather Network boffins aren't used to absolutes. "50% chance of Scorpius this month... with a possibility of Orion blowing in from the northeast."
*The correct answer (not opinion) is Orion.