Messier 46, NGC 2438 and the Calabash nebula

Constellation: Vela

Messier 46, also known as NGC 2437, is aopen cluster in the constellation Puppis. It is located about 5’000 Ly away, and is estimated to contain about 500 stars. The planetary nebula NGC 2438, which appears to lie within the cluster near its northern edge is most likely unrelated since it does not share the cluster’s radial velocity. Link to interactive sky chart.

The Calabash nebula also known as the Rotten Egg nebula and OH 231.84 +4.22, is a member of the cluster as it shares the radial velocity and proper motion of Messier 46. is a protoplanetary nebula*. It is 770 yrs old,[1] 1.4 Ly long and is located 4’200 Ly away.

* A protoplanetary nebula or preplanetary nebula (PPN, plural PPNe) is an astronomical object, which is at the short-lived episode during a star’s rapid evolution between its late life and the subsequent planetary nebula phase. A PPN emits strongly in infrared radiation, and is a kind of reflection nebula.

[1] Alcolea, J., Bujarrabal, V., Sánchez Contreras, C., Neri, R., and Zweigle, J., The highly collimated bipolar outflow of OH 231.8+4.2, Astronomy and Astrophysics, vol. 373, EDP, pp. 932–949, 2001. doi:10.1051/0004-6361:20010535.

NGC 2348 (West) and the Calabash nebula (East)

Telescope & Mount:

PlaneWave CDK17 (F6.8) on a Software Bisque Paramount ME mount.

Imaging:

Camera: Player One Zeus-Mono (bin 2×2)

Data:
Ha: 60x600s
O3: 55x600s

Stars:
Red: 120x60s
Green: 120x60s
Blue: 120x60s

Total integration time: 25h 10′