The Dolphin Nebula is an emission nebula of Wolf-Rayet -type. It has been created by the Wolf-Rayet star WR6 (EZ Canis Majoris, bright blue star in the middle of the nebula) which shines brightly in UV, having over 600,000 times the luminosity of the sun despite being only 26 times heavier. The nebula is heavily dominated by the OIII emissions, with the "brains" of the Dolphin highlighted also in Ha.
At -24° declination the Dolphin flies almost directly overhead in Chile during January which was the optimal time to get a high-resolution image of this popular target. In the end, the 8-hour Ha and OIII stacks both had a mean 2.2" FWHM as measured by PixInsight's FWHMEccentricity.
The brightest stars of the image, including the red-orange super-giant o¹ Canis Majoris, are part of the open cluster Collinder 121 which extends to the right of the image.
A pleasant surprise was the presence of a round bubble at the bottom edge of the nebula, which after some research was found to be the planetary nebula candidate PNG 234.9-09.7, discovered in 2008 as part of the AAO/UKST Ha survey[1]. It is faintly visible both in Ha and OIII.
[1]:
https://ui.adsabs.harvard.edu/abs/2008MNRAS.384..525M/abstract
Thanks for looking, I highly recommend taking a look at the full-size version!
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