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We present a 1620 A image of the nearby globular cluster NGC 6752 obtainedwith the Ultraviolet Imaging Telescope (UIT) during the Astro-2 mission of theSpace Shuttle Endeavour in 1995 March. An ultraviolet-visible color-magnitudediagram (CMD) is derived for 216 stars matched with the visible photometry ofBuonanno et al. (1986). This CMD provides a nearly complete census of the hothorizontal branch (HB) population with good temperature and luminositydiscrimination for comparison with theoretical tracks. The observed data showgood agreement with the theoretical zero-age horizontal branch (ZAHB) ofSweigart (1996) for an assumed reddening of E(B-V) = 0.05 and a distancemodulus of 13.05. The observed HB luminosity width is in excellent agreementwith the theoretical models and supports the single star scenario for theorigin of extreme horizontal branch (EHB) stars. However, only four stars canbe identified as post-EHB stars, whereas almost three times this many areexpected from the HB number counts. If this effect is not a statisticalanomaly, then some non-canonical effect may be decreasing the post-EHBlifetime. The recent non-canonical models of Sweigart (1996), which havehelium-enriched envelopes due to mixing along the red giant branch, cannotexplain the deficit of post-EHB stars, but might be better able to explaintheir luminosity distribution.Comment: 14 pages, AASTeX, includes 4 EPS figures ApJ Letters accepte

Ultraviolet Imagery of NGC 6752: A Test of Extreme Horizontal Branch Models