Heart Nebula (IC 1805)

History

On 3 November 1787, the German-British astronomer Wilhelm Herschel discovered a nebula in the constellation Cassiopeia, which he designated as WH III 695. John L. E. Dreyer included it in 1888 as NGC 896 in his «New General Catalogue of Nebulae and Clusters of Stars» and described it as follows: «very weak, rather large, irregular shape». In 1890 the American astronomer Edward Barnard photographed the same section of the sky and discovered a «foggy spot» a little northeast at the location noted for NGC 896, which John L. E. Dreyer unwittingly included in his second «Index Catalogue» as IC 1795 as a double entry for NGC 896. Presumably Herschel only saw the brightest western part of IC 1795. About one degree southeast of this nebula Barnard discovered another large nebula in which an open star cluster was embedded. This then became IC 1805. [196]

NGC 896, IC 1795, IC 1805
NGC 896, IC 1795, IC 1805: Heart Nebula in Cassiopeia; TS Triplet APO 90, Reducer Photoline 0.79 (490mm / f5.44), SBIG ST-8300; 28L x 300 sec 1×1, 218R, 28G, 24B 2×2 300 sec; Bernese Highlands; © 2018 Bernhard Blank, Dragan Vogel
NGC 896, IC 1795, IC 1805
NGC 896, IC 1795, IC 1805: Heart Nebula in Cassiopeia; Celestron RASA 11" f/2.22; ZWO ASI6200 Pro; Tentlingen; © 2020 Peter Kocher

Physical Properties

All objects (NGC 896, IC 1795 and IC 1805) are connected to one another, large H-II area and form the «Heart Nebula», which is formed by the young O and B stars in the star cluster in IC 1805 (Collinder 26, Melotte 15) can be excited to glow. On Simbad a distance of 4.1 kpc (13'400 light years) is found for IC 1795. For IC 1805 one finds distances of 1.7 kpc to 6.1 kpc (around 5500 to 20'000 light years). The real distance is probably somewhere in between. [145]

Etwa 2.5 Grad weiter westlich befindet sich ein weiterer Nebel, den «Seelennebel» (Soul Nebula). Beide Nebel werden gerne zusammen als «Herz- und Seelennebel» bezeichnet.

Revised+Historic NGC/IC, Version 22/9, © Dr. Wolfgang Steinicke [277]
NameRADecTypebMagvMagDimDreyer DescriptionIdentification, Remarks
NGC 89602 25 27.8+62 01 10EN10 × 10eF, pL, iFIC 1795, LBN 645, CED 6, SG 1.04, Min 2-57, narrrow dark lane n-s, SNR ?
IC 179502 25 27.8+62 01 10dup10 × 10Patch of nebyNGC 896, LBN 645, CED 6, SG 1.04, Min 2-57, narrrow dark lane n-s, SNR ?
IC 180502 32 48.0+61 27 42OCL (III3pn)6.520Cl, co, eL neby extends fOCL 352, Mel 15, LBN 654

Finder Chart

The Heart Nebula is located in the constellation Cassiopeia. In Central Europe it is circumpolar. The best time to observe, however, is July to January, when the constellation is highest at night.

Chart Heart Nebula (IC 1805)
Heart Nebula (IC 1805) in constellation Cassiopeia. Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

More Objects Nearby (±15°)

References

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
196Celestial Atlas by Curtney Seligman; cseligman.com/text/atlas.htm (2020-12-28)
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)