Sh2-42 is located in a region of the Milky Way in Sagittarius with faint Ha background nebulosity. Its distance is approximately 4800 light years.
Originally catalogued as an emission nebula by Stewart Sharpless in the 1950's, this was spectroscopically confirmed to be a planetary nebula in 2003 in the MASH survey.
The bright 2 arcminute central shell showing nice internal structures is surrounded by a faint halo with a size of 6 arcminutes that is predominantly OIII.
Sh2-42 also exhibits slight hints of interaction with the ISM (interstellar medium) and is categorised as WZO 2 in the WZO PN-ISM interaction scheme.
(Caption by Sakib Rasool)
Ha-OIII-RGB (400-400-140-140-140min), total 20,3 h, Seeing 0.9-1.3 arcsec, North is up;
80cm f/7 Astrooptik Keller corrected cassegrain, FLI Proline 16803, Astrodon Gen2 filters, Prompt 7 CTIO Chile
Processing: Johannes Schedler
Find the Ha-O3-RGB Version in 33/80% size and a Ha-O3 comparison below