NGC 6210

NGC 6210, sometimes also known as the Turtle Nebula or simply the Turtle, is a planetary nebula located approximately 5.4 ± 1.3 kly from the Sun in the constellation of Hercules. It is a bright nebula. It is positioned about 38° above the galactic plane at a vertical distance of about 3.3 kilolight-years (1 kpc), this is unusually high for a nebula. Due to its position, it has little extinction from intervening interstellar dust. The nebula formed as a result of material being shed from a low mass progenitor star less massive than the Sun (~0.9 M☉) the complex structure and appearance of NGC 6210 has led to proposals that the nebula was shaped by mass transfer in a triple star system. This object was first recorded as a star-like feature by Joseph Lalande on March 22, 1799. However, credit for the discovery of a nebula goes to Wilhelm Struve in 1825. John L. E. Dreyer described it as, "a planetary nebula, very bright, very small, round, disc and border". The structure of NGC 6210 is complex having an unusual morphology being described as very amorphous and irregular in shape (rough ellipsoid) about 0.5 light years in radius. The nebula contains shells, lobes, knots, and haloes.