NGC 7129 is a reflection nebula located in the constellation Cepheus. It is a compact and active star-forming region, often noted for its soft blue glow and the cluster of young stars embedded within it. Unlike purely emission nebulae, NGC 7129 shines mainly by reflecting the light of nearby hot stars off surrounding dust, giving it a cooler, bluish appearance.

The nebula lies about 3,000 light-years from Earth and spans only a few light-years across, making it relatively small compared to large diffuse nebulae. At its center is a group of very young, massive stars that have recently formed from the surrounding molecular cloud. These stars illuminate the nebula and are gradually clearing away the gas and dust from which they were born.