UBVI data of open cluster Trumpler 27

The spiral structure of the Milky Way inside the solar circle is still poorly known because of the high density of the material that causes strong extinction towards the...太阳轨道圆（solar circle）内的银河系螺旋结构目前仍未得到充分认知，这是由于该区域内星际物质密度极高，会对观测方向造成强烈的消光（extinction），进而……