Bipolar Nebula NGC 6164-5

 

clic for 36% size 1154 x 769 (270 kB)

clic here for 60% size 3206 x 2106 (1400 kB)

About this Image

This peculiar bipolar nebula NGC 6164/6165 seems to be a relic from former outbursts of the bright central star.
This star is an unusually massive star nearing the end of its life. The star, visible in the center of the above image and catalogued as HD 148937 emits ultraviolet light and heats up gas that surrounds it. That gas was likely thrown off from the star, possibly by its fast rotation. Even the faint outer shells seem to be related to outbursts from this star. Expelled material might have been further channeled by the magnetic field of the star, creating the symmetric shape of the bipolar nebula.
Several cometary knots of gas are also visible on the lower left and upper right similar as in the Helix and Eskimo Nebula.
NGC 6164-5 spans about four light years and is located about 4,000 light years away toward the southern constellation Norma.
North is down.

Compare a Gemini close-up of this area and more background information: here.
Checkout a deep image of this area by Don Goldman here.

Below you see the high resolved center crop of the above image in 40/80 % size showing the fine details of the nebula in H-alpha light.

clic for 80% size 960 x 956 (171 kB)


Technical Details
Optics

20 " Keller cassegrain in corrected secondary focus at f/9

Mount Liebscher GEM
Camera SBIG STL-11000M at -15 to -20C, 8-pos STL filter wheel
Filters Baader RGB, H-alpha, (7 nm)
Date May 01/04, 2008.
Location IAS/Hakos Namibia
Sky Conditions dark skies, raw FWHM Ha: 1.3-1.4", raw FWHM RGB: 1.8-2.1"
temperature 10-15 C,
Exposure R:G:B = 30:30:30 minutes (10-minute sub-exposures); synthetic luminance used;
Ha: 3 x 60 min subexposures
Programs used Maxim DL 4.5
CCDStack
Photoshop CS3