Lemon Slice Nebula (IC 3568)

IC 3568
IC 3568: Aufnahme mit dem Hubble Weltraumteleskop. © ESA/Hubble & NASA, Judy Schmidt [165]


This planetary nebula was discovered on 31 August 1900 by the American astronomer Robert Grant Aitken with the 12" Clark-Refractor at Lick Observatory. He was looking at Comet Borrelly-Brooks and noticed that the star BD +83° 357 was surrounded by a small circular nebula. This was confirmed with the 36" Refractor the next night. [277]

IC 3568 was misclassified as a compact galaxy UGC 7731 in the «Uppsala General Catalogue», published in 1973. [459] It also appeared 1989 as PGC 41662 in the «Catalogue of Principal Galaxies». [144]

The PN probably received its nickname «Lemon Slice Nebula» in 1997 due to a publishing of an image [537] taken with the Hubble Space Telescope where it was rendered yellow and looked like a slice of lemon.

Physical Properties

Simbad lists the following magnitudes measured in different spectral bands: B 11.809, V 10.73, g 10.791, R 12.651, r 11.782, i 12.387, J 11.368, H 11.398, K 10.844. Distances are given ranging from 2265 pc to pc. [145]

«Strasbourg-ESO Catalogue of Galactic Planetary Nebulae» Acker et al., 1992 [141]
DesignationsPN G123.6+34.5: IC 3568, PK 123+34.1, ARO 56, VV 63, VV' 111
Right Ascension (J2000.0)12h 33m 07s
Declination (J2000.0)+82° 33' 50"
Dimensions 10." (optical)
Distance 1.31 kpc
Radial Velocity-41.1 km/s ± 0.8 km/s
Expansion Velocity 7.8 km/s (O-III)
C-Star DesignationsAG +82 365, AG82 147, BD +83 357, GCRV 7565, HD 109540
C-Star Magnitude13.73 mag (B filter), 13.45 mag (V filter)
C-Star Spectral TypeO3(H)
DiscovererAITKEN 1900

Finder Chart

The planetary nebula IC 3568 is located within the IAU boundary of the inconspicuous constellation Camelopardalis, but it lies closer to the more conspicuous constellation Ursa Minor, roughly between Polaris and the box of the Little Dipper. The PN is thus easily observable all year round.

Chart Lemon Slice Nebula (IC 3568)
Lemon Slice Nebula (IC 3568) in constellation Camelopardalis. Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

More Objects Nearby (±20°)


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)
144Catalogue of Principal Galaxies (PGC); Paturel G., Fouque P., Bottinelli L., Gouguenheim L.; Astron. Astrophys. Suppl. Ser. 80, 299 (1989); cdsarc.unistra.fr/viz-bin/cat/VII/119 (2021-02-18)
145SIMBAD astronomical database; simbad.u-strasbg.fr/simbad
149SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
165Flickr: Judy Schmidt; flickr.com/people/geckzilla (2021-01-02)
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)
459«Uppsala General Catalogue of Galaxies (UGC)» Nilson 1973; cdsarc.cds.unistra.fr/viz-bin/cat/VII/26D (2021-12-23)
537Round Planetary Nebula IC 3568; hubblesite.org/contents/media/images/1997/38/568-Image.html (2022-09-24)