Historical Identification: Per Dreyer, IC 800 (Javelle #219, 1860 RA 12 26 52, NPD 73 51.7) is "faint, small, round, gradually brighter middle."
Physical Information: Based on recessional velocity of 2325 km/sec, about 100 million light years away. Given that and apparent size of 1.5 by 1.0 arcmins, about 45 thousand light years across. Listed as a member (VCC 1532) of the Virgo Cluster.

Historical Identification: Per Dreyer, IC 801 (Swift list IX (#34), 1860 RA 12 27 08, NPD 36 57.6) is "most extremely faint, small, round, star close to north."
Physical Information: Apparent size 1.2 by 1.0 arcmin?

Historical Identification: Per Dreyer, IC 802 (Bigourdan #174, 1860 RA 12 30 28, NPD 14 56) is "very faint, small, stellar."

Historical Identification: Per Dreyer, IC 803 (Javelle #220, 1860 RA 12 32 35, NPD 72 39.2) is "extremely faint, small, very difficult."
Physical Information: Apparent size of PGC 42367 about 0.9 by 0.15 arcmin? Of PGC 215034 about 1.0 by 0.3 arcmin?
Usage By The Arp Atlas: IC 803 is used by the Arp Atlas as an example of a galaxy with a jet, but the "jets" are simply amorphous structures created by the interaction of the pair. (check Arp Atlas notes)

Historical Identification: Per Dreyer, IC 804 (Swift list VII (#22), 1860 RA 12 33 57, NPD 94 15.7) is "very faint, very small, round."
Physical Information: Apparent size 1.0 by 0.6 arcmin?

Historical Identification: Per Dreyer, IC 805 (Swift list VIII (#65), 1860 RA 12 34 14, NPD 75 29.6) is "very faint, pretty large, round, 2 stars (to) north and north-following (to northeast)."
Physical Information: This entry will only contain historical information; for anything else see NGC 4611.

Historical Identification: Per Dreyer, IC 806 (Javelle #221, 1860 RA 12 34 50, NPD 106 35.0) is "extremely faint, extremely small, round, 12th magnitude star close."
Physical Information: Apparent size 0.7 by 0.6 arcmin?

Historical Identification: Per Dreyer, IC 807 (Javelle #222, 1860 RA 12 34 54, NPD 106 38.3) is "pretty faint, very small, round, gradually brighter middle."
Physical Information: Apparent size 0.7 by 0.7 arcmin?

Historical Identification: Per Dreyer, IC 808 (Bigourdan #175, 1860 RA 12 34 58, NPD 69 17) is "a small nebulous cluster."
Physical Information:

Historical Identification: Per Dreyer, IC 809 (Swift list VII (#23), 1860 RA 12 35 02, NPD 77 29.4) is "extremely faint, pretty small, round, M59 to south."
Physical Information: Apparent size 1.0 by 1.0 arcmin? Listed as a member (VCC 1910) of the Virgo Cluster.

Historical Identification: Per Dreyer, IC 810 (Swift list VII (#24), 1860 RA 12 35 04, NPD 76 38.1) is "extremely faint, pretty small, much extended."
Physical Information: Apparent size 1.6 by 0.5 arcmin? Listed as a member (VCC 1912) of the Virgo Cluster.

Historical Identification: Per Dreyer, IC 811 (Bigourdan #176, 1860 RA 12 37 31, NPD 99 26) is "a nbulous 13th magnitude star, south-following (to southeast of) II 558," WH 558 being ??.
Physical Information: This entry will only contain historical information; for anything else see NGC 4663.

Historical Identification: Per Dreyer, IC 812 (Javelle #752, 1860 RA 12 37 39, NPD 93 39.9) is "pretty bright, small, round, nucleus = 13th magnitude."
Physical Information: Apparent size 0.8 by 0.5 arcmin?

Historical Identification: Per Dreyer, IC 813 (Spitaler #20, 1860 RA 12 38 17, NPD 66 11.9) is "faint, pretty small, irregularly round, brighter middle."
Physical Information: Apparent size 0.9 by 0.8 arcmin?

Historical Identification: Per Dreyer, IC 814 (Javelle #753, 1860 RA 12 38 19, NPD 97 19.7) is "pretty bright, very small, round, mottled but not resolved."
Physical Information: Apparent size 0.7 by 0.3 arcmin?

Historical Identification: Per Dreyer, IC 815 (Javelle #223, 1860 RA 12 39 21, NPD 77 21.5) is "faint, very small, 14th magnitude star involved."
Physical Information: Apparent size 0.5 by 0.3 arcmin? Listed as a member (VCC 2038) of the Virgo Cluster.

Historical Identification: Per Dreyer, IC 816 (Swift list VII (#25), 1860 RA 12 39 39, NPD 79 22.9) is "most extremely faint, very small, round, double star north-following (to northeast), north-preceding (northwestern) of 2," the other being IC 817.
Physical Information: Apparent size 0.9 by 0.7 arcmin? Listed as a member (VCC 2044) of the Virgo Cluster.

Historical Identification: Per Dreyer, IC 817 (Swift list VII (#26), 1860 RA 12 39 54, NPD 79 22.4) is "most extremely faint, very small, round, south-following (southeastern) of 2," the other being IC 816.
Physical Information: Apparent size 0.6 by 0.5 arcmin? Listed as a member (VCC 2046) of the Virgo Cluster.

Historical Identification: Per Dreyer, IC 818 (Spitaler #50, 1860 RA 12 39 55, NPD 59 29.8) is "very small, round, brighter middle, 12th magnitude star north-following (to northeast) 2½ arcmin."
Physical Information: Apparent size 0.9 by 0.2 arcmin?

Historical Identification: Per Dreyer, IC 819 (Spitaler #51, 1860 RA 12 40 21, NPD 58 30.0) is "(part of a) double nebula, connected, very faint, very small, south-following (southeastern) one brighter," the other member of the double nebula being IC 820.
Discovery Notes: Herschel observed the two galaxies as a "possibly bi-nuclear" nebula, while Spitaler observed them as separate objects, leading Dreyer to give the separate nebulae individual IC listings, despite the pair already being cataloged as Herschel's NGC listing. For anything other than historical information, see NGC 4676.

Historical Identification: Per Dreyer, IC 820 (Spitaler #52, 1860 RA 12 40 22, NPD 58 30.8) is "(part of a) double nebula, connected, very faint, very small, south-following (southeastern) one brighter," the other member of the double nebula being IC 819.
Discovery Notes: Herschel observed the two galaxies as a "possibly bi-nuclear" nebula, while Spitaler observed them as separate objects, leading Dreyer to give the separate nebulae individual IC listings, despite the pair already being cataloged as Herschel's NGC listing. For anything other than historical information, see NGC 4676.

Historical Identification: Per Dreyer, IC 821 (Spitaler #53, 1860 RA 12 40 37, NPD 59 26.8) is "round, pretty large, gradually a little brighter middle, 2 stars south-south-following (to south-southeast)."
Physical Information: Apparent size 1.1 by 1.1 arcmin?

Historical Identification: Per Dreyer, IC 822 (Spitaler #54, 1860 RA 12 40 56, NPD 59 10) is "faint, extremely small, brighter middle."
Physical Information: Apparent size 0.4 by 0.4 arcmin?

Historical Identification: Per Dreyer, IC 823 (Bigourdan #177, 1860 RA 12 40 58, NPD 62 02) is "suspected, 2 arcmin south of II 381," WH II 381 being NGC 4692. The second IC adds "Not in Wolf's list III."
Possible Alternative: Corwin lists another possible (though in his opinion less likely candidate) as the magnitude 14.8 star at RA 12 47 55.1, Dec +27 11 32.
Misidentification By HyperLEDA: LEDA misidentifies IC 823 as a duplicate observation of NGC 4692; but since Bigourdan's original note and Dreyer's IC entry make it clear that it is near but not the NGC object, the LEDA entry is an inexplicable blunder.

Historical Identification: Per Dreyer, IC 824 (Javelle #754, 1860 RA 12 42 29, NPD 93 48.6) is "pretty bright, pretty large, extended preceding-following (west-east), bi-nuclear."
Physical Information: This entry will only be concerned with historical information; for anything else see NGC 4678.

Historical Identification: Per Dreyer, IC 825 (Swift list VII (#27), 1860 RA 12 43 02, NPD 94 36.9) is "most extremely faint, pretty small, round, nearly between 2 stars."
Physical Information: Apparent size 0.6 by 0.3 arcmin?

Historical Identification: Per Dreyer, IC 826 (Spitaler #55, 1860 RA 12 44 33, NPD 58 10.8) is "faint, pretty small, round, gradually brighter middle."
Physical Information: Apparent size 0.6 by 0.6 arcmin?

Historical Identification: Per Dreyer, IC 817 (Javelle #224, 1860 RA 12 44 53, NPD 72 57.9) is "very faint, small, extended preceding-following (west-east), diffuse."
Physical Information: Apparent size 0.9 by 0.5 arcmin?

Historical Identification: Per Dreyer, IC 828 (Javelle #755, 1860 RA 12 45 00, NPD 97 22.0) is "faint, very small, round, nucleus = 13.5 magnitude."
Physical Information: Apparent size 0.8 by 0.3 arcmin?

Historical Identification: Per Dreyer, IC 829 (Bigourdan #178, 1860 RA 12 45 07, NPD 104 46) is "a nebulous 13th magnitude star."
Physical Information: Apparent size 0.7 by 0.6 arcmin?

Historical Identification: Per Dreyer, IC 830 (Swift list IX (#35), 1860 RA 12 45 09, NPD 35 33.4) is "very faint, very small, a little extended, stellar."
Physical Information: Apparent size 0.8 by 0.4 arcmin?

Historical Identification: Per Dreyer, IC 831 (Spitaler #56, 1860 RA 12 45 52, NPD 62 46.5) is "faint, small, round, brighter middle."
Physical Information: Apparent size 0.7 by 0.3 arcmin?

Historical Identification: Per Dreyer, IC 832 (Safford #22, Spitaler #57, 1860 RA 12 47 10, NPD 62 49.5) is "faint, small, round, brighter middle, double star north-following (to northeast)."
Physical Information: Apparent size 0.5 by 0.5 arcmin?

Historical Identification: Per Dreyer, IC 833 (Swift list VIII (#66), 1860 RA 12 49 27, NPD 95 58.1) is "very faint, small, round."
Physical Information: Apparent size 0.3 by 0.2 arcmin?

Historical Identification: Per Dreyer, IC 834 (Spitaler #58, 1860 RA 12 49 28, NPD 62 54.5) is "pretty faint, pretty small, suddenly brighter middle." The second IC lists a corrected RA (per Wolf list III) of 12 49 43.
Physical Information: Apparent size 0.5 by 0.3 arcmin?

Historical Identification: Per Dreyer, IC 835 (Spitaler #59, 1860 RA 12 50 03, NPD 62 46.5) is "faint, small, round."
Physical Information: Apparent size 0.6 by 0.6 arcmin?

Historical Identification: Per Dreyer, IC 836 (Swift list VII (#28), 1860 RA 12 50 21, NPD 25 37.4) is "most extremely faint, very small, very difficult, between 2 stars."
Physical Information: Apparent size 1.3 by 0.2 arcmin?

Historical Identification: Per Dreyer, IC 837 (Spitaler #60, 1860 RA 12 50 42, NPD 62 45) is "faint, small, round."
Physical Information: Apparent size 0.9 by 0.2 arcmin?

Historical Identification: Per Dreyer, IC 838 (Spitaler (#61), 1860 RA 12 51 28, NPD 62 51) is "very faint, 1½ arcmin north-following (to northeast of) (NGC) 4849."
Physical Information: Apparent size 0.5 by 0.5 arcmin? Sometimes unnecessarily called NGC 4849A due to its proximity to NGC 4849

Historical Identification: Per Dreyer, IC 839 (Bigourdan #179, 1860 RA 12 51 31, NPD 61 06) is "stellar, 13th magnitude." The position precesses to RA 12 58 17.2, Dec +28 08 34, about 1.1 arcmin west-southwest of the pair of galaxies often misidentified as NGC 4851 and IC 839, and about the same distance north-northeast of the galaxy listed above (see the entry for NGC 4851 for more about that mess). The key to deciding which of the objects in question is what Bigourdan actually observed lies in Bigourdan's "Big Book" (published much later than the list used by Dreyer for the IC1), and is discussed in the following paragraph.
 On page E215 of Bigourdan's volume for stars with (1900) right ascensions of 12 hours (S94 in my list of Historical References), he states that he observed NGC 4851 on the same date as his #179, and that it was (averaging two measurements) 9.35 seconds of time to the west of and 3' 15.5" south of a 12th magnitude star located at (1900) RA 12 53 41.45, Dec +28 44 33.6; while on page E217 he lists a single observation of Bigourdan 179 as being 16.44 seconds of time to the west of and 4' 30.4" to the south of the same comparison star. Precessing the star's position yields (2000) RA 12 58 31.3, Dec +28 12 09, which is nearly but not quite exactly the same as the position of a 12th magnitude star located at RA 12 58 30.8, Dec +28 12 06.6. Precessing that backwards, the correct 1900 position of the star was RA 12 53 40.96, Dec +28 44 31.1, and adding the offsets for Bigourdan 179 yields a position for the nebula of (1900) RA 12 53 24.52, Dec +28 40 00.7 = (2000) 12 58 14.5, Dec +28 07 35.6, which falls on the western rim of the galaxy listed above. Further confirmation of the identification comes from its description, which is far more appropriate for that galaxy than for the galaxies to its northeast, and from the difference in position Bigourdan measured for the two objects, placing "NGC 4851" 7.1 seconds of time to the east and 1' 15" to the north of Bigourdan 179, which compares well to the actual difference in position of 6.7 seconds of time and 1' 20". In other words, IC 839 is definitely not the companion of NGC 4851, as often stated in the literature, but the galaxy listed here, which lies about 2 arcmin to the southwest of the NGC object. (A big thank-you to Steve Gottlieb for replying to my query about the mess involving NGC 4851, and pointing out the error involving IC 839, which led to my correcting and completing this entry years earlier than I might have otherwise done.)
Note About PGC Designation(s): As discussed in the entry for NGC 4851, a search of LEDA for IC 839 incorrectly returns an entry for PGC 44439, the northeastern "companion" (albeit only an optical double) of NGC 4851; so to search LEDA for the correct IC 839, use PGC 44423.
Physical Information: Based on a recessional velocity relative to the Cosmic Background Radiation of 7735 km/sec (and H₀ = 70 km/sec/Mpc), a straightforward calculation indicates that IC 839 is about 360 million light years away. However, for objects at such distances we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the galaxy was about 350 million light years away at the time the light by which we see it was emitted, about 355 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of about 0.47 by 0.15 arcmin (from the images below), the galaxy is about 45 to 50 thousand light years across.

Historical Identification: Per Dreyer, IC 840 (Javelle #756, 1860 RA 12 51 41, NPD 78 36.5) is "faint, small, a little brighter middle, mottled but not resolved."
Physical Information: Apparent size 0.8 by 0.6 arcmin?

Historical Identification: Per Dreyer, IC 841 (H. C. Wilson, 1860 RA 12 52 26±, NPD 67 24) is "very faint (Astronomy and Astrophysics, No. 103)." The second IC lists a corrected position (per Wolf list VI) of RA 12 52 56, NPD 67 25.9.
Physical Information: Apparent size 0.9 by 0.3 arcmin?

Historical Identification: Per Dreyer, NGC 842 (Safford #2, 1860 RA 12 53 54, NPD 60 12.0) is "pretty faint." The position precesses to RA 13 00 38.2, Dec +29 02 41,
Physical Information: Apparent size 1.2 by 0.6 arcmin?

Historical Identification: Per Dreyer, IC 843 (Safford #3, 1860 RA 12 54 54, NPD 60 12.7) is "faint, brighter middle and nucleus." The position precesses to RA 13 01 37.8, Dec +29 02 02, only about 1.4 arcmin west-southwest of the galaxy listed above, the description is reasonable and there is nothing comparable within 5 arcmin, so the identification is essentially certain. Unfortunately, for unknown reasons, the galaxy nearly 6 arcmin to the north of Safford's position has been called IC 843 for donkey's years, hence the warning in the title for this entry that that galaxy, PGC 44908, is not IC 843, despite the fact that all catalogs and atlases list it as such.
Discovery Note: On May 3, 1866, Safford discovered two objects in this region. For reasons involving an extremely belated publication of his observations, his discovery of those objects was not noticed in time to be properly included in the NGC, but Dreyer listed both of them (as IC 842 and 843) in the First Index Catalog. Both galaxies lie along the same parallel of declination, and given the way that observers of the 19th century scanned the sky, their nearly identical declinations (both in the sky and in Safford's list of 'novae') make it virtually certain that they are the two objects he observed. But as noted above, for unknown reasons, the galaxy nearly 6 arcmin to the north (PGC 44908) is the one that is universally listed as IC 843, and when Safford's #3 was rediscovered, it became IC 4088. Still, just because something has been called by the wrong name for many years does not make that right; it just makes it confusing. So this entry serves as a notice of the historical and continuing error, the entry for PGC 44908 describes the nature of the galaxy "formerly" known as IC 843, and as noted below, the entry for IC 4088 discusses the galaxy that is really Safford's #3.
Physical Information: Given the long history of calling this galaxy IC 4088, and the recent realization that it is probably NGC 4913, see those entries for anything else.

Historical Identification: Per Dreyer, IC 844 (Ormond Stone (#585), 1860 RA 12 55 40, NPD 119 46.1) is "very faint, very small, a little brighter middle." The position precesses to RA 13 03 18.2, Dec -30 31 18, almost dead center on the galaxy listed above, the description fits and there is nothing else nearby, so the identification is certain.
Discovery Notes: Although Dreyer credited Stone because he was the principal author of Southern Nebulae, the table in that paper shows that Frank Muller was the actual observer.
 Turner's observation was uncovered by Yann Pothier in Jan 2020, while examining the sketch-books of the observers for the Great Melbourne Telescope. On the date shown above, Turner thought he was sketching the region near GC 3378, which is NGC 4936; but that would have looked "round", and what Turner saw was "elongated". Based on the star-field drawn by Turner, it seems certain that what he observed was the galaxy 12 arcmin to the west of NGC 4936, which is the one listed above, so although he misidentified it as a previously known object (and thereby lost a chance to be included in the original list of NGC discoverers), he was apparently the first to actually observe what became IC 844. Still, since it was misidentified, Turner's observation was never published, so Muller's discovery was a completely independent one, and since his observation was published, he deserves just as much (and some would argue even more) credit.
Physical Information: Based on a recessional velocity relative to the Cosmic Microwave Background radiation of 3225 km/sec (and H₀ = 70 km/sec/Mpc), IC 844 is about 150 million light-years away, in reasonable agreement with redshift-independent distance estimates of about 95 to 140 million light-years. Given that and its apparent size of about ? arcmin (from the images below), the galaxy is about ? thousand light-years across.
NED 1.6 x .4 arcmin

Historical Identification: Per Dreyer, IC 845 (Swift list VIII (#67), 1860 RA 12 58 20, NPD 77 08?) is "most extremely faint, small, round, faint star near preceding (to the west)."
Physical Information: Apparent size 0.3 by 0.3 arcmin?

Historical Identification: Per Dreyer, IC 846 (Javelle #225, 1860 RA 12 58 33, NPD 66 09.2) is "very faint, round, a little brighter middle, difficult."
Physical Information: Apparent size 1.1 by 1.0 arcmin?

Historical Identification: Per Dreyer, IC 847 (Swift list IX (#36), 1860 RA 12 59 57, NPD 35 34.0) is "very faint, small, round, between 2 stars." The second IC adds "= (WH) III 782, NGC 4974. Rümker's place agrees." The position precesses to RA 13 05 57.3, Dec +53 40 59, about 0.9 arcmin north-northwest of NGC 4974, seeminly agreeing with the IC2 identification, and about 3 arcmin east-southeast of the galay listed above, which would therefore seem to be a less likely identification. However, based on a note by Corwin, there are problems with the IC position and the description ("between two stars") does not fit NGC 4974, so as shown above and discussed immediately below, IC 847 must actually be NGC 4973.
Discovery Note: Rümker's later observations were not published until 1895, too late to add to the first Index Catalog, so "Rümker's place agrees" had to wait for the IC2. (Thanks to Wolfgang Steinicke for that information.)
Discussion of Historical (Mis)identification (1): Usually, the NGC/IC positions are essentially the same as those given by the original observer, albeit often precessed from some different equinox to the one for 1860. But Swift's paper gives the position as (1890) RA 13 00 45, Dec +54 16.3, which precesses to (1860) RA 12 59 27.3, Dec +54 25 59, which is 30 seconds of time to the west of the NGC position, and precesses to (2000) RA 13 05 28.2, Dec +53 40 56, only about 1.2 arcmin west-southwest of NGC 4973 and over 4.4 arcmin west-northwest of NGC 4974. In addition, NGC 4974 does not lie between two stars, while NGC 4973 does (they are about 9 arcmin apart, but Swift used a very large field of view, so they would have seemed reasonably close to him). As a result, it is certain that the IC position was incorrect, IC 847 is a duplicate observation of NGC 4973, and although Rümker accurately observed WH III 782 (which later became NGC 4974), that had nothing to do with what Swift observed.
Discussion of Historical (Mis)identification (2): In his list of 'novae' discovered in 1899 and 1900 and published in 1900 Howe gave a position of (1899) RA 13 01 16, Dec +54 13.2, which precesses to (2000) RA 13 05 35.8, Dec +53 40 45, and lies less than 0.7 arcmin southeast of IC 847, about which he wrote "No. 19 is near [IC] (847); [NGC] 4973 and 4974, according to the NGC, follow [lie to the east of] No. 19 less than a minute of time; but their relative positions are not the same as those of (847) and No. 19. I looked for them on one night, when the seeing was poor, and could not be sure of them." In a separate paper, also published in 1900, Howe writes "(847). The 'bt. 2 st' given in the Index Catalogue, I cannot verify from my sketch of the field of view." As noted above, this is probably because the stars are 9 arcmin apart, and although they would seem reasonably close to the nebula in Swift's very large field of view, Howe used a much smaller field of view, and probably couldn't have seen both the stars and the nebulae in the region.
 Finally, it should be pointed out that there is a note in the second IC stating that NGC 4973 is the same as Howe's #19, so since that is IC 847 (though Dreyer did not realize that), the identification of IC 847 as NGC 4973 is actually more than a century old.
Physical Information: Given the duplicate entry, see NGC 4973 for anything else.

Historical Identification: Per Dreyer, IC 848 (Javelle #226, 1860 RA 13 00 07, NPD 73 15.0) is "extremely faint, very small, difficult."
Physical Information: Apparent size 0.8 by 0.6 arcmin?

Historical Identification: Per Dreyer, IC 849 (Javelle #757, 1860 RA 13 00 27, NPD 90 10.6) is "faint, pretty large, round, gradually brighter middle."
Physical Information: Apparent size 1.6 by 1.3 arcmin?