Milky Way field giants from Gaia & APASS I-band

The calibration of the tip of the red giant branch (TRGB) in the I-band has a direct role in determinations of the Hubble constant, a subject of recent interest due to the...I波段下红巨星支尖端（Tip of the Red Giant Branch，TRGB）的定标，对哈勃常数的测定具有直接作用；该研究主题近年来因相关因素引发了广泛关注。