NGC7293 · Helix Nebula
| Chinese name | 螺旋星云 |
|---|---|
| Type | Planetary nebula |
| Constellation | Aqr |
| RA | 22h30m |
| Dec | −21° |
| Apparent magnitude | 7.6ᵐ |
| Hemisphere | Southern |
| Best season | Autumn |
| Difficulty | Moderate |
| Focal length | 中长焦 800–1200mm |
About
The Helix Nebula (NGC 7293, Caldwell 63) lies only about 650 light-years away in Aquarius and is one of the nearest bright planetary nebulae, nicknamed the "Eye of God" for its resemblance to a giant eye. Spanning nearly the size of the full moon, it is the gas shell cast off by a Sun-like star reaching its end. A teal O III inner disk is ringed by layers of red hydrogen and nitrogen, and its inner walls bristle with thousands of "cometary knots" pointing toward the central white dwarf, each larger than our solar system and of great scientific interest. Being close and large on the sky, it reveals its grand form and rich detail even at medium-to-long focal lengths, the most photogenic planetary nebula of the southern autumn.