That’s a question I’ve seen pop up a few times over the last few days.
The answer: any place with an unobstructed view of the sunset in the west.
In St. John’s, that means you’ll have to go to a place like Signal Hill, in order to look over the city. If you don’t want to risk any city related obstructions, drive to Topsail beach or a similar place where you can see the sun set over Conception Bay. Other places on the island will no doubt have similar sunset points.
Once you’re in one of these sunset locations, wait until the sun sets. Panstarrs is close to the horizon where the sun has just set, but you’ll have to wait about 40 minutes until the twilight sky becomes dark enough to actually make out the comet.
Don’t expect an obvious target until after March 10, and even then bring binoculars for a proper look. March 12 and 13 may be the best days of all, because a crescent moon will accompany the comet in the sky!
Finally, here’s that link to the Panstarrs sky viewing charts again.
Update: March 18, I finally got a chance to see the comet, see it here.