Octatonic scales?

[geopianoincanada]

How do I try to understand these scales?

I'm doing book study with my professor (she received her music education from the Soviet music school system) while I limit my piano playing due to the arm issues (waiting to hear back from doctor whether surgery is needed or not) and even she can't quite make sense out of Octatonic scales in RCM Level 7 theory.

The clumsy explanations I find for Octatonic scales and their patterns just don't lend themselves to memorization very well if at all.

[liszt-and-the-galops]

A quick search turned up that octatonic scales are scales that follow either a whole-half-whole-half... or a half-whole-half-whole... pattern, as opposed to major (whole-whole-half-whole-whole-whole-half) or minor (whole-half-whole-whole-half-whole-whole).

[thorn]

With octatonic scales there are only three patterns to remember:
C-Db-Eb-E-F#-G-A-Bb
C#-D-E-F-G-Ab-Bb-B
D-Eb-F-Gb-Ab-A-B-C

For the 'half-whole' mode you begin on the first note, for the 'whole-half' mode you begin on the second note. Off the top of my head, a couple of pieces that use octatonic harmony are Scriabin's 6th Sonata and Messiaen's Le baiser de l'enfant Jésus. Both to completely different effect!

[rachmaninoff_forever]

Pick a note and alternate between whole step and half step

OR

pick a note and alternate between half step and whole step

OR

Put two diminished chords a half step apart right next to eachother

OR

put two diminished chords a whole step apart from eachother

[geopianoincanada]

Thanks to all who helped!

[keypeg]

The octatonic scale also fits with the fully diminished chord.
The whole tone scale (which you'll probably also get) fits with the augmented chord.