Following my recent post showing a well known planetary nebula (NGC 2438) in the open star cluster M46, I was contacted by another astronomer who claimed that there are two other PNs in M46. This surprised me and I asked him to advise the designations, so I could look them up.
He responded by marking the objects on a photo, although he did not advise the designations. So I was sceptical – until I located them both on my own image.
I did some research and found the two additional objects are:
PK 231+4.1
AKA: Minkowski 1-18; PNG231.4+04.3; W44
Magnitude: 14.0
Dia: 0.5′
RA: 07 : 42 : 55.07
Dec: -14 : 23: 58.4
OH 231.84 +4.22
AKA: Rotten Egg nebula or Calabash nebula
Magnitude: 9.5
Dia: 1′
RA: 07 : 42 : 16.83
Dec: -14 : 42 : 52.1
The image above is my own, with PK 231+4.1 and OH 231.84 +4.22 circled.
I then discovered here that yet another PN is also in the vicinity of M46 – but sadly it fell just outside my FOV. It is:
BMP J0739-1418 or PN G231.1+03.9.
AKA: PN G231.1+0.3.9
Magnitude: +15
Dia: 2.5′
RA: 07 39 50.5577980710
Dec: -14 18 25.880005865
So M46, apparently, has not just one – but four planetaries.
Related:
Image © R.Powell
Cosmic Focus 
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