In Flames Gig!

I'm going to see In Flames in 2 weeks!!
Sept 29th at Manchester Academy 1 supported by:
Sonic Syndicate
Gojira
Volbeat (not 100% sure about that though)

Finally seeing my fav band live

Drop Tuning (a#?) (newbie)

Right I've never drop tuned my guitar before.
I want to play some In Flames songs, and I saw that they're in a weird tuning:
A# F A# D# G C from thickest to thinnest

I have a few questions

1) Is this A# tuning?

2) Could it damage my guitar in any way?

3) I don't know what gauge strings I have, how do I find out?

btw I have an ESP LTD AX-50 if that changes anything

Hi

Hi I'm Alex.
I'm from England (Manchester), I've been a drummer and singer in bands and a week ago I decided to get a guitar.
SO HERE I AM.
I do metal. melodic death metal.
I have an ESP AX-50 and Marshall mg15dfx and I can play a few chords and a couple of scales but otherwise I am an absolute beginner.

anyway hi