Abstract
Effective temperatures and surface gravities for 48 main sequence band B and A stars were found by matching optical region spectrophotometry and Hγ profiles with the predictions of ATLAS9 solar composition model atmospheres. When these values were compared with those found using Strömgren uvby β photometry based on ATLAS6 model atmospheres, we found a difference (photometry-spectrophotometry) of $25\pm 118$ K for 29 stars with 8000 K ≤ Teff ≤ 10 050 K compared to 76 ± 105 K for 14 stars with 10 050 K ≤ Teff ≤ 17 000 K. The surface gravity scales are in agreement. These stars are sufficiently hot that their effective temperatures and surface gravity determinations are unaffected by discrepancies due to the choice of Mixing-Length or Canuto-Mazzitelli convection theories.