Abell 70 with Galaxy PMN J2033-0656

Abell 70
Abell 70: Section of PanSTARRS/DR1 [147]


The annular planetary nebula Abell 70 was discovered on the «Palomar Observatory Sky Survey» photo plates by George Abell in 1955. The designation in the first publication was A55 57 and in the second A66 70. [331, 332]

Physical Properties

It is a very special deep-sky object: At its northern edge it is illuminated by a spindle-shaped background galaxy. The galaxy, which is probably several million light-years away from us, appears to be about the same size in length as the relatively close PN, which happens to be in the line of sight between us and the distant galaxy. Distance estimates from Abell 70 range from 2.4 to 3.5 kiloparsecs. The PN is moving towards us at a radial speed of around 79 km/s. Measurements of the expansion speed based on the OIII lines showed that the nebula expands at 38 km/s. [141]

— 1996, Philipp Reza Heck

«Strasbourg-ESO Catalogue of Galactic Planetary Nebulae» Acker et al., 1992 [141]
DesignationsPN G038.1-25.4: A 70, PK 38-25.1, A55 57, ARO 351, VV' 536
Right Ascension (J2000.0)20h 31m 33s
Declination (J2000.0)-07° 05' 21"
Dimensions 42." (optical)
Radial Velocity-79.0 km/s ± 18.0 km/s
Expansion Velocity 37.8 km/s (O-III)
C-Star DesignationsAG82 410
C-Star Magnitude19.1 mag (B filter)
DiscovererABELL 1955

Galaxie PMN J2033-0656

The galaxy behind the northern edge of the PN is apparently a radio galaxy with the designation PMN J2033-0656 from the Parkes-MIT-NRAO Survey - this according to the information from the NASA Extragalactic Database (NED), which refers to an article in APJS (1995, 97, p.347, Griffith). Other names are 2MASX J20313312-0705014 or WISEA J203133.10-070501.5. The redshift z is 0.019423, which corresponds to a speed of 5823 km/s.

Further infos at CDS: 2MASX J20313312-0705014

Finder Chart

The unequal pair lies between the constellations Aquila (Eagle) and Aquarius (Water Bearer). A good starting point is the 3.8 mag bright star Albali (ε Aquarii). About 4.5 degrees northwest of it in the direction of θ Aquilae you will experience an unusual encounter. A large telescope aperture and a dark sky are essential for the visual observation of this fine pair of objects. This object is best observed in the months of August to October.

Chart Abell 70 with Galaxy PMN J2033-0656
Abell 70 with Galaxy PMN J2033-0656 in constellation Aquila. Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

More Objects Nearby (±15°)


141Strasbourg-ESO Catalogue of Galactic Planetary Nebulae; A. Acker, F. Ochsenbein, B. Stenholm, R. Tylenda, J. Marcout, C. Schohn; European Southern Observatory; ISBN 3-923524-41-2 (1992); cdsarc.unistra.fr/viz-bin/cat/V/84 (2021-02-18)
147Aladin Lite; aladin.u-strasbg.fr/AladinLite (2020-12-23)
149SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
331«Globular Clusters and Planetary Nebulae Discovered on the National Geographic Society-Palomar Observatory Sky Survey» Abell, G. O.; Publications of the Astronomical Society of the Pacific, Vol. 67, No. 397, p.258-261, August 1955; DOI:10.1086/126815; Bibcode:1955PASP...67..258A
332«Properties of Some Old Planetary Nebulae» Abell, G. O.; Astrophysical Journal, vol. 144, p.259, April 1966; DOI:10.1086/148602; Bibcode:1966ApJ...144..259A