We present new VI photometry for the halo globular cluster M30 ( NGC 7099 = C2137-174 ) , and compute luminosity functions ( LFs ) in both bands for samples of about 15,000 hydrogen-burning stars from near the tip of the red giant branch ( RGB ) to over four magnitudes below the main-sequence ( MS ) turnoff .
We confirm previously observed features of the LF that are at odds with canonical theoretical predictions : an excess of stars on subgiant branch ( SGB ) approximately 0.4 mag above the turnoff and an excess number of RGB stars relative to MS stars .

Based on subdwarfs with Hipparcos -measured parallaxes , we compute apparent distance moduli of ( m - M ) _ { V } = 14.87 \pm 0.12 and 14.65 \pm 0.12 for reddenings of E ( V - I ) = 0.06 and 0.02 respectively .
The implied luminosity for the horizontal branch ( HB ) at these distances is M _ { V } ^ { HB } = 0.11 and 0.37 mag .
The two helium indicators we have been able to measure ( R and \Delta ) both indicate that M30 ’ s helium content is high relative to other clusters of similar metallicity .
M30 has a larger value for the parameter \Delta V _ { TO } ^ { HB } than any of the other similarly metal-poor clusters for which this quantity can be reliably measured .
This suggests that M30 has either a larger age or higher helium content than all of the other metal-poor clusters examined .
The color-difference method for measuring relative ages indicates that M30 is coeval with the metal-poor clusters M68 and M92 .