NGC 6164-65 is a very special diffuse nebula on the edge of the huge diffuse nebula NGC 6188. The latter one is in the constellation Ara (The Altar) but the former one is already in Norma (The Protractor). They are also in a similar distance: about 4000 light-years away. Although it looks like a planetary nebula it is an emission nebula created and excited by the bright O-type star HD 148937 in the center. I had previously thought that this was a Wolf-Rayet bubble (i.e. a shell created by a massive hot star that is rapidly losing matter) but this is something more special. According to more recent studies the central binary star (HD 148937) was previously a triple system. Two of the components merged which led partly to the "rejuvenation" of one of the stars and partly to the formation of the nebula.

In the 16" telescope the entire nebula is faint but the two blobs on each side of the central star can still be considered sort of bright. In my drawing the one on the left is NGC 6164 and the one on the right is NGC 6165. The latter one is larger, has no real center, is more diffuse, and perhaps a little brighter. A faint tail is attached to it. The former one exhibits a slightly brighter central region. A very faint, diffuse and interesting S-shaped thread connects the two blobs starting from the central star.

The central region depicted in the drawing is surrounded by a much larger very faint halo, a baroquely chiseled bubble which as far as I remember was very faintly visible with an [OIII] filter in the 16" telescope. The [OIII] filter didn't really change the appearance of the central part.

Comparison with the photograph

You can see a photo of NGC 6164-65 on the left made with the 2.61m VLT Survey Telescope along with my inverted rotated and cropped 16" drawing.