NGC 7293 (The Helix Nebula) - Planetary Nebula in Aquarius

Ha(Lum)-HaR-HaG-HaB narrowband and color combination (Click for a larger view 1600 x 1600 px)


NGC 7293 (The Helix Nebula) - Planetary Nebula in Aquarius

Discovered by Karl Ludwig Harding before 1824.

NGC 7293 - The Helix Nebula is one of the closest of all planetary nebulae: Lying at a distance of perhaps 700 light years towards the constellation Aquarius, it is the only planetary nebula for which a parallax could be obtained by ground-based observations. The Helix Nebula (NGC 7293), is a well studied and nearby example of a Planetary Nebula, typical of this final phase of stellar evolution. The white dot at the Helix's center is it's hot, a sun-like central star. The remnant central stellar core, destined to become a white dwarf star, glows in light so energetic it causes the previously expelled gas to fluoresce. The surprisingly complex geometry can be seen on the image from Hubble site ( The main ring of the nebula is actually composed of inner and outer ellipsoidal shaped rings which are inclined almost perpendicular to each other. The innermost ring has a diameter of about 1.7 light years. The inner ring is surrounded by a toroidal shaped outer ring with a diameter of 3 light years. An extreme outer arc exists with a diameter of about 6 light years and probably represents recently ionized gas released much earlier during the stars red giant phase.

North is up. The Horizontal FOV is about 35' (slight crop from original FOV). The image almost centered at:

Right Ascension 22 : 29.6 (h:m)
Declination -20 : 48 (deg:m)
Distance 0.7 (kly)
Brightness 7.3 (mag)
Apparent Dimension

16' x 28' (arc min)

Seeing: Pickering 8 rating - Very Good
Optic(s): RC 12" with Astro-Physics corrector @ f/5
Mount: ASA DDM85 Premium
Camera: ATIK 4000 - monochrome CCD – 2048 x 2048 px ; 16x16 mm; 7.4 µm x 7.4 µm
Filters: Astronomik Ha, R, G, B, SupaSlim TrueTechnology Computerized Filter Wheel
Dates/Times: 2012-08-18
Location: IRIDA Observatory, BG, longitude: E 24 44' 18", latitude: N 41 41' 42"
Exposure Details:

Ha = 4*20min=80 min and 4*10min = 40 min, total Ha=120 min, R=30 min, G= 30 min, B = 30 min (Bin 1), subs. 10 and 20 min, Total Exposure Time 210 min

More details: Dark and flat frames reduction
Guiding: All subexposures are unguided

PixInsight / PS


All Contents copyright Velimir Popov unless otherwise noted.