NGC 6164 / 5

NGC 6164-5 is a small emission nebula in Norma whose appearance in a telescope is adversely affected by the brightness of its central star, 6.8-magnitude HD 148937. a massive O-type supergiant of 40 solar masses.  Its dual NGC entry refers to the nebulas two brightest crescents, discovered by Sir John Herschel in 1834 while observing from the Cape of Good Hope in Africa   NGC 6164 lies immediately northwest of the central star, while NGC 6165 lies immediately southeast of it.  The two crescents are formed as this rotating star throws of energetic gases from its intense UV light.  The magnetic field of the large star further channels the gases forming the symmetrical bipolar nebula.

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