piano scale
A♯ harmonic major
Major with a flattened sixth: the mirror of harmonic minor, and the reason a major key can borrow a minor subdominant.
The same sounds spelled from the other side are B♭ harmonic major.
Written out
Every accidental is written in, rather than left to a key signature, so the letters can be read one at a time.
The step pattern
What is true of it
A♯ harmonic major is A♯, B♯, C𝄪, D♯, E♯, F♯ and G𝄪, and back to A♯.
Its steps are W – W – H – W – H – W+H – H, where W is a whole step and H a half.
Written correctly it needs 9 alterations, C𝄪 and G𝄪 among them. That is what the letters force, and it is also why nobody writes music in this key: the same notes spelled from the other side are easier to read.
On the same tonic, A♯ major differs from it by exactly one note.
Chords made only of these notes
Found by testing every chord in the catalogue against these 7 sounds, not chosen.
Other scales on A♯
C harm majC♯ harm majD♭ harm majD harm majD♯ harm majE♭ harm majE harm majF harm majall 374