B33 - the 'Horsehead' - is a dark nebula, superimposed on a stretch of glowing hydrogen gas.
The 'Flame Nebula' ( NGC2024) is located in this image below Alnitak ( Zeta Orionis), the 'left' star of Orion's Belt.
Canon EOS 20D Modified Canon 20D mounted on a TMB 80mm/F6 + Televue 0.8x reducer/flattener. Halpha ( Astronomik Ha, 13nm): 12x600sec/ISO800; RGB ( IDAS-LPS): 15x300sec/ISO800. Calibration and stacking, averaging, color balancing, sharpening in Images Plus and Photoshop CS2.