According to McCarthy (1984) the objects detected in objective prism surveys for Hα emission line are a ”most unnatural“ group. Of course they consist of many natural groupings whose identities or other peculiarities could become apparent after observing them with higher dispersion and resolution spectroscopy. In some cases, however, their galactic locations and associations with other known populations, can provide a clue to their population types.
The aims of the objective prism surveys using the Bosscha Schmidt telescope can be broadly categorised as follows:
1.Searches for galactic planetary nebulae in the region 240° < l < 360 °; |b| ≤ 10°, initiated by The (1968).
2.Searches for T-Tauri stars in some southern dark clouds (Shinohara, Ogura & Hidayat 1989).
3.Searches for variations in Hα intensities and luminous emission stars in some selected galactic regions, such as in the Puppis and Carina regions.