I had a small window of just over 3 hours between weeks of clouds to image something. My wonderful friend, Uwe, who had just posted a beautiful image of M46 (
https://astrob.in/khb4u3/D/), which also happened to have displayed the PN, NGC2438, suggested I give NGC2438 a try with my C11". Despite the very limited time, I gave it a try and was surprised by the relatively strong Ha and OIII signals. So, here is a HOO version but I did not have RGB stars. So, Uwe came through and sent me his LRGB stars from his image (
), which I incorporated only the RGB into my image, as the point here was to emphasize the PN and not get overwhelmed by the L data of the cluster. The star colors really popped out around the PN. I also decided to use more of the yellowish/red palette to represent the Ha vs. the more traditional all red, just to give it a little different look (the advantages of NB creativity!) Overall, I think it came out well, especially being happily surprised by the few unexpected hours.
Interesting note: NGC2438 is a planetary nebula in the southern constellation of Puppis. Its central star is roughly 1,370 light-years from Earth. NGC 2428 appears to lie within the cluster M46, but
it is most likely unrelated, being another example of a superposed pairing.
What could have been and will try next year (🤞).........This is a multi-shell planetary nebula with a bright inner nebula, consisting of two somewhat detached shells. The structure is surrounded by a fainter, mostly circular halo that is more visible on the western half. I point this out because I could see remnants of this on my overstretched Ha stacked image, but I simply did not have enough data to bring it out in a presentable way
. So, this will definitely be a target for next season, which I suspect I will need around 15 hours or so to really display this aspect of the PN.
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