NGC 1840
 
NGC 1840 is a open cluster located in the constellation of Mensa. The NGC is a catalog of 7,840 nebulae, star clusters, and galaxies. Here are the key stats on NGC 1840:
| NGC: | NGC 1840 | 
| Type: | open cluster | 
| Constellation: | Mensa | 
| Right Ascension: | 05:05:19.16 | 
| Declination: | -71:45:46.40 | 
| Major axis: | 0.8 ' | 
| Minor axis: | 0.7 ' | 
| Angle (major axis): | 80° | 
Right Ascension (RA) units = HH:MM:SS.SS
Declination (Dec) units = DD:MM:SS.SS