guitar scale
F♯ Mixolydian
F♯1G♯2A♯3B4C♯5D♯6E♭7
Major with a flattened seventh: the scale that fits a dominant seventh chord without altering it.
The same sounds spelled from the other side are G♭ Mixolydian.
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
F♯WG♯WA♯HBWC♯WD♯HEWF♯
What is true of it
F♯ Mixolydian is F♯, G♯, A♯, B, C♯, D♯ and E, and back to F♯.
Its steps are W – W – H – W – W – H – W, where W is a whole step and H a half.
On the same tonic, F♯ major differs from it by exactly one note.
Across the first twelve frets of the guitar its notes fall in 45 places, which is what makes a scale a shape rather than a list.
Chords made only of these notes
C♯mminorC♯m7minor seventhD♯mminorD♯m7minor seventhEmajorEmaj7major seventhF♯majorF♯7dominant seventh
Found by testing every chord in the catalogue against these 7 sounds, not chosen.