The maqams (Arabic for position) can be called scales or modes and are common in music from the Middle East and in Turkish Ottoman classical music ("Makam" can be translated to scales or modes in Turkish). One of the things that distinguish a maqam from a scale is that a maqam sometimes use quarter tones (a pitch between two semi-notes, e.g. a tone between F# and G).

There are lots of maqams that are organized into several groups and not very easy to grasp at the first moment. The scale illustrations below will give you a short introduction to Arabic maqams. As you can see the scales in different keys also have specific names. Maqams often begins on C, D, Eb (quarter-flat), F, G, A or Bb (quarter-flat).

C (Hijaz Kar Maqam)

C Hijaz Kar Maqam scale diagram
Notes: C, Db, E, F, G, Ab, B, C

D (Shahnaz)

D Shahnaz scale diagram
Notes: D, Eb, F#, G, A, Bb, C#, D

Eb (Maqam Mustar)

Eb Maqam Mustar scale diagram
Notes: Eb, F#, G, A, Bb, C, D, Eb

F (Maqam Jiharkah)

F Maqam Jiharkah scale diagram
Notes: F, G, A, Bb, C, D, Eb, F

G (Shadd Araban)

G Shadd Araban scale diagram
Notes: G, Ab, B, C, D, Eb, F#, G

A (Suzidil)

A Suzidil scale diagram
Notes: A, Bb, C#, D, E, F, G#, A

Bb (Ajam Maqam)

Bb Ajam Maqam scale diagram
Notes: Bb, C, D, Eb, F, G, A#, Bb

As you can see the intervals differs in the scales above. The interval steps with quarter tones are written like 3/4. For example in Eb (Maqam Mustar) the intervals are: 3/4 - 1- 3/4 - 3/4 - 1 - 1 - 3/4.

For further reading can be recommended.