RCW 44 (aka ESO 166−PN 21, Wr 17-31 y PN 277.7–3.5) was studied in detail by a group of Mexicans astronomers of the UNAM. (Mexico National Autonomous University). The used a 4 m telescope in Cerro Tololo to study the object and a 0.9 m telescope to get images. It was determinate a v magnitude of 17.94 and a distance of 1.2 kpc. The authors of the research are Peña, M.; Ruiz, M. T.; Bergeron, P.; Torres-Peimbert, S.; Heathcote, S and it was published by 1997. The RWC catalogue is a collection of very faint Ha emission objects discovered from Australia. This nebula has a circular morphology, where filamentary structures can be seen that seem to envelop the sphere composed of gas and dust.