Hey Phil, first of thank you for the donation. That's really a nice gesture and I really appreciate it!
I saw that there's an issue when displaying the image, probably font size issue since we all use different font sizes and display resolutions. I'll see what I can do and the fixes will reflect on the next update. Sorry for that!
About the Penta and Penta Blue only in Ionian and Aeolian: the main reason why I decided to show the pentatonic only in these 2 modes is because for Ionian it would naturally falls to the Major Penta and for Aeolian for the Minor Penta we all know. The added blue note for Major Penta forms the Major Blues Scale and for the Minor Penta forms the Minor Blues Scale.
We could, for any other mode, derive the respective Penta(s), maybe we could call it "Modal Pentatonics", but if we do so, it's very important to pay attention when choosing the notes to form this desired Penta. Let's see an example, let's take the full scale A Lydian:
R maj2 maj3 aug4 P5 maj6 maj7
A B C# D# E F# G#
which 5 notes would we choose from those 7 notes above?
- we can compare the lydian scale with A major scale: A B C# D E F# G# , because the Lydian scale can be thought of a major scale with an aug4th, so the only different note when comparing is the D# or aug4th , this note D# we will for sure choose as one of the 5 notes
- by looking at the Lydian scale we can definitely say that the Penta we want is going to be some kind of Major Penta type. The A Major Penta notes are: A B C# E F# , but since we want the D# to give us the Lydian sound we need to replace 1 note from the A Major Penta.
- One option is to replace of the 5th: A B C# D# F#
- but we could replace 5th and instead of using the 6th, replace it for the 7th : A B C# D# G#
As you see, there's not an strict rule, except that we need the characteristic note(s) added in order to construct a modal pentatonic. I probably don't play this way when playing something modal, I believe i'm thinking full modal scale? One of the reasons I decided to not include presets for modal pentatonics.
Hope that info above helps ...
When experimenting with this scale "mods", you'll notice that sometimes we end with some "uncomfortable" playing shapes.