Seems like "pabha" is made up of two parts... from the PED:
Pa = Directional prefix of forward motion, in applied sense often emphasizing the action as carried on in a marked degree or even beyond its mark. Thus the sphere of pa -- may be characterized in following:
1. forth, forward, out; "papatati" = fall forward, i.e. down;
2. intensive in a marked degree, more than ordinarily; "pabhāti" = shine forth;
3. onward; "pavattati" = move on;
4. in front of, before; "padvāra" = before the door;
5. [PED definition unclear, but I think "reflexion"]; "pakūjin" = signing out to (each other).
Bhā = the light, splendour.
Pabhā = shine, radiance (the light that goes forward; onward; is intensive; in front; reflexive).
Candappabhā = moonshine (or the light of the moon that goes forward; onward; etc).