So, given my track record of theorizing on G4’s magic, guess I have a duty here.

First of all, chanting isn’t necessary for magic, as Twilight has stated in the past. Opaline’s just stating part of the rune matrix aloud. This is perhaps an attempt to invoke some magic inherent in alicorndom and funnel it into the spell - which is obvious, but what IS that spell?

I think it may be an attempt at a scrying spell, with extra power necessary to force its way past the Empire’s cloaking enchantment. The archetecture that is shown for those few seconds is very reminiscent of the crystal empire, especially given the coloration and gaps at each point of the ‘star’. My guess is that Opaline is trying to gain Equestria’s magic, in an effort to get access to the crystal empire - why THAT location is more important to her than anything else, we have yet to see…

Misty should have been placed outside the castle and possibly this would work out properly for Opaline.