Famous "Moon hunters" from Hawaii discovering small remote moons of Saturn (impossible to see by Cassini's cameras), but Cassini discovering small close moons of Saturn (impossible to see from the Earth).
They replenish in moon hunting very perfectly! :)
Some other interesting facts about S/2007 S4...
I can't found at the Web any information about visual brightness of S/2007 S4, but from estimation of diameter, albedo and brightness of neigbouring moons: Methone & Pallene - I thinking so S/2004 S4 has only a. +26.0 mag of visual brightness (= 100 million times fainter than the faintest stars visible to naked eye).
For comparison: Saturn's brightness (at opposition) is about 0.7 mag, so S/2007 S4 is shining fainter by about 25.3 mag. The corresponding difference in brightness is over 13 billion times!
This moon is in elliptical prograde orbit (eccentricity e = 0.0010) with a semimajor axis a = 197,700 km. At pericenter (closest to the planet) S/2007 S4 is separated from the Saturn a distance of q = 197,502 km. At apocenter (furthest from the planet) this moon is separated from the Saturn a distance of Q = 197,898 km.
Angular diameter of the Saturn's disc as observed from this moon is over 35 degrees! (or 70 The Moon's discs). Maximum brightness of the planet as observed from S/2007 S4 is -18.4 mag!
Whereas, this moon as observed near the planet (Saturn hasn't solid surface), has only 3 arcsec od diameter and +7.0 mag of brightness. Future astronauts from this place, can't see this moon! :)
And last interesting fact. These three little moons: Methone, S/2007 S4 and Pallene they have similar rotation periods - quite over 1 earthy day. Therefore the closest approach of S/2007 S4 and Pallene is possible every 10,3 days (i.e. synodic period of these moons), but the closest approach of Methone and S/2007 S4 is more rarely: only every 41,1 days!
BTW: The absolute record holders of the lenght of synodic period are Epimetheus and Janus (over 1400 days or almost 4 years!)