Historical Identification: Per Dreyer, NGC 7800 (= GC 5039 = JH 2291 = WH II 10, 1860 RA 23 52 26, NPD 75 58.4) is "faint, pretty small, extended 39°." The position precesses to RA 23 59 35.5, Dec +14 48 22, only 0.3 arcmin west-southwest of the center of the galaxy listed above and well within its outline, so the identification is certain.
Discovery Note: Per Gottlieb, John Herschel's first catalogued record of this object was made on Sep 12, 1828; but he also observed it in his very first sweep, on Nov 2, 1823, as shown above. Since that was his first observation on his own (he had made others with his father), his methods for accurately measuring positions were not well developed, and his position was about 6 arcmin to the southeast of the galaxy listed above; but three other objects (out of nine) that he observed on that sweep made it into his GC, his description of #6 in the first sweep is reasonably close to his later one, and there is nothing else anywhere in the region, so there is no doubt that NGC 7800 was observed on the earlier date. Of course, William Herschel's earlier observation takes precedence, so the fact that his son observed the object years before the officially published date isn't terribly important, but it is an interesting footnote to the history of the NGC.
Physical Information: Based on a recessional velocity relative to the Cosmic Microwave Background radiation of 1395 km/sec (and H₀ = 70 km/sec/Mpc), NGC 7800 is about 65 million light-years away, in reasonable agreement with redshift-independent distance estimates of about 70 to 80 million light-years. Given that and its apparent size of about 2.25 by 1.25 arcmin (from the images below), the galaxy is about 40 to 45 thousand light-years across.

Historical Identification: Per Dreyer, NGC 7801 (= GC 5040 = JH 2292, 1860 RA 23 53 18, NPD 40 03.6) is "a cluster, pretty rich, pretty compressed, stars from 9th magnitude." Corwin quotes Herschel's description as "A double star in a tolerable cluster in which is one star 9 m." Dreyer's position precesses to RA 00 00 25.2, Dec +50 43 10, about 1.4 arcmin south of the double star that defines the position noted above, but given the size of the cluster (variously estimated as five to fifteen arcmin) the error is insignificant, so the identification is certain.
Description Notes: As an example of differing interpretations of the cluster, Gottlieb visually saw it as "three dozen stars in a coarse 12' x 6' group. The rectangular outline is elongated 2:1 N-S", while Corwin saw it on a DSS image as "20-30 stars covering an area about 15 arcmin by 11 arcmin", and writes that Brian Skiff called it an "asterism, center defined as position of a wide magnitude 12 pair". In other words, between Dreyer and Herschel's differing descriptions (neither of which says anything about the size of the cluster) and three modern opinions, where the group is located is certain, but exactly how much of the surrounding starfield should be included in the group is about as clear as mud.
Physical Information: Long exposure photographs emphasize a multitude of faint background stars, making the scatter of brighter ones harder to notice. If it is assumed, based on the description as "pretty rich", that the cluster includes all the moderately bright stars in the region, then it is about 10 arcmin across. Whether the stars really are a cluster or just a random scattering of stars is a matter for further investigation.

Historical Identification: Per Dreyer, NGC 7802 (= GC 5041 = JH 2293, 1860 RA 23 53 50, NPD 84 32.1) is "very faint, small, round, pretty suddenly brighter middle." The position precesses to RA 00 01 00.1, Dec +06 14 40, within 0.2 arcmin of the center of the galaxy listed above, and the bright nucleus would have made it appear round to a visual observer, so the identification is certain.
Physical Information:Based on a recessional velocity relative to the Cosmic Microwave Background radiation of 4960 km/sec (and H₀ = 70 km/sec/Mpc), NGC 7802 is about 230 million light-years away. Given that and its apparent size of about 1.05 by 0.55 arcmin (from the images below), the galaxy is about 70 thousand light-years across.

Historical Identification: Per Dreyer, NGC 7803 (Swift list VI (#98), 1860 RA 23 53 58, NPD 77 39.3) is "pretty faint, pretty small, round, faint star very near north-precessing (to northwest)." The second IC lists a corrected RA (per Howe) of 23 54 10. The corrected position precesses to RA 00 01 19.9, Dec +13 07 28, only 0.8 arcmin north of the galaxy listed above, and the size and brightness of the galaxy and the 14th magnitude star to the northwest make the identification certain.
Physical Information: As a member of a Hickson Compact Group, the best estimate of the distance of the Group's members should use all the information for each of them. For 100A (NGC 7803), that is a recessional velocity relative to the Cosmic Microwave Background radiation of 4965 km/sec. For 100B (PGC 108), the corresponding value is 4895 km/sec; for 100C (PGC 89) it is 5100 km/sec; and for 100D (PGC 92) it is 5230 km/sec. There are no redshift-independent distance estimates for any of the four galaxies, so the average of their recessional velocities (about 5045 to 5050 km/sec) is the best value to use to estimate their distance (the variation in the numbers is well within normal ranges for "peculiar velocities" [random motions relative to their neighbors] in such a group). Using that (and H₀ = 70 km/sec/Mpc), the Group should be about 235 million light-years away. Given that and its apparent size of about (1.0 by 0.5) arcmin (from the images below), NGC 7803 is about 65 to 70 thousand light-years across. The Group is considered to be part of the NGC 7810 Group of galaxies, of which NGC 7810 is the brightest member.

Physical Information: PGC 108 is listed as a member of the NGC 7810 Group of galaxies, which also includes NGC 7803. It is also a member of Hickson Compact Group 100, which consists of NGC 7803, PGC 108, PGC 89 and PGC 92. See the discussion of the distance of HCG 100 in the entry for NGC 7803. Given the estimated distance of about 235 million light-years for that Group, and the apparent size of about 0.5 by 0.35 arcmin (from the image below) for PGC 108, that galaxy is about 35 thousand light-years across.

Physical Information: PGC 89 is listed as a member of the NGC 7810 Group of galaxies, which also includes NGC 7803. It is also a member of Hickson Compact Group 100, which consists of NGC 7803, PGC 108, PGC 89 and PGC 92. See the discussion of the distance of HCG 100 in the entry for NGC 7803. Given the estimated distance of about 235 million light-years for that Group, and the apparent size of about 0.65 by 0.25 arcmin (from the image below) for PGC 89, that galaxy is about 45 thousand light-years across.

Physical Information: PGC 92 is listed as a member of the NGC 7810 Group of galaxies, which also includes NGC 7803. It is also a member of Hickson Compact Group 100, which consists of NGC 7803, PGC 108, PGC 89 and PGC 92. See the discussion of the distance of HCG 100 in the entry for NGC 7803. Given the estimated distance of about 235 million light-years for that Group, and the apparent size of about 0.5 by 0.15 arcmin (from the image below) for PGC 92, that galaxy is about 35 thousand light-years across.

Physical Information: Apparent size 0.45 by 0.3 arcmin (from the image below); nothing else known, but thought to be a dwarf irregular galaxy, and far closer to us than its apparent companions in HCG 100.

Historical Identification: Per Dreyer, NGC 7804 (= GC 6235, Schweizer, 1860 RA 23 54 09, NPD 83 01.9) is "very faint, a double star, nebulous?" and includes an end-note which adds "...and observed by Bredichin in 1875. Described as faint, extended, a little brighter south-preceding (southwest)... Engelhardt in 4 observations could only see a double star without nebulosity." (Bredikin was Schweizer's successor, and both their observations were published in 1875's volume 2 of the Observations de Moscou.) The first IC adds (per Burnham) "to be struck out, only a faint double star without nebulosity." Burnham's description was correct, as the NGC position precesses to RA 00 01 19.0, Dec +07 44 52, less than 0.1 arcmin southeast of the double star listed above (which is closer to the pair than the two stars are to each other), and the southwestern star is the brighter, so the identification is certain.
Physical Information: Burnham estimated the magnitudes of the pair as 12.5 for the southwestern star, and 13.0 for the northeastern one. As shown in the description line, modern measuremens put the combined brightness of the pair at magnitud 12.3.

Historical Identification: Per Dreyer, NGC 7805 (= GC 5042 = JH 2294 = WH III 855, 1860 RA 23 54 18, NPD 59 20.5) is "extremely faint, small, round, suddenly brighter middle, stellar, south-preceding (southwestern) of 2," the other being NGC 7806. The position precesses to RA 00 01 27.2, Dec +31 26 16, only a quarter arcmin northeast of the center of the galaxy listed above, and the position of the other galaxy makes the identification certain.
JH Observations Note: Steinicke lists JH's observation as sweep 104, Nov 17, 1827, while Gottlieb lists it as sweep 178, Sep 16, 1878. JH's Slough paper of 1833 states that he observed JH 2294 on three dates (also noted by Gottlieb). The earliest one (sweep 104), "extremely faint, seen by glimpses in a fog", only has the NPD; the second one (sweep 114), "extremely faint, very little more than a suspicion, and could not find the object again", gives the RA and NPD; and the third (sweep 178), "extremely faint, small, round, suddenly brighter middle, double, the south-preceding (southwestern) of 2", also gives the RA and NPD. So the first date (per Steinicke) is the first time JH observed this object, and the last date (per Gottlieb) is the first complete record. Of course, since the original discovery was William Herschel's, exactly when John observed the object isn't of great importance; but I've added this so that anyone running across differing dates for JH 2294 will know the reason for the discrepancy.
Physical Information: Since NGC 7805 and 7806 are an interacting pair, any estimate of their distance should be based on an average of whatever information is available for each of them. For 7805, that is a recessional velocity relative to the Cosmic Microwave Background radiation of about 4480 km/sec; while for NGC 7806, we have a comparable recessional velocity of about 4450 km/sec, and redshift-independent distance estimates of about 220 to 230 million light-years. Using an average recessional velocity of about 4465 km/sec (and H₀ = 70 km/sec/Mpc), the pair are about 205 to 210 million light-years away, in reasonable agreement with the redshift-independent distance estimates. Using 215 million light-years as a compromise between the two methods of determining the distance, NGC 7805's apparent size of about 0.55 by 0.45 arcmin for the main galaxy and about 1.05 by 0.75 for its extended halo (from the images below) suggests that the galaxy is about 35 thousand light-years across, and its halo spans about 65thousand light-years.
Group Membership: The pair of galaxies comprising Arp 112 are listed as members of the NGC 7831 Group, along with NGC 7819, 7836 and more than a dozen other galaxies.
Use By The Arp Atlas: NGC 7805 and 7806 are used by the Arp Atlas of Peculiar Galaxies as an example of an elliptical galaxy (NGC 7805) repelling spiral arms (in NGC 7806), without any supplementary note. (On the page showing Arp's photo the image has North on the bottom, so it is reversed from the images shown here.)

Physical Information: Based on a recessional velocity relative to the Cosmic Background Radiation of about 12,200 km/sec (and H₀ = 70 km/sec/Mpc), a straightforward calculation indicates that PGC 1944121 is about 565 to 570 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 540 to 545 million light-years away at the time the light by which we see it was emitted, about 550 to 555 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 0.4 by 0.3 arcmin (from the image below), the galaxy is about 60 to 65 thousand light-years across.
Note About "Apparent" Companionship: Since this object is far beyond its "apparent" neighbors, it is only a background galaxy, and has no actual connection to them.

Historical Identification: Per Dreyer, NGC 7806 (= GC 5043 = JH 2295 = WH III 856, 1860 RA 23 54 20, NPD 59 19.9) is "extremely faint, small, round, stellar, north-following (northeastern) of 2," the other being NGC 7805. The position precesses to RA 00 01 29.3, Dec +31 26 52, only 0.4 arcmin northwest of the center of the galaxy listed above, and the position of the other galaxy makes the identification certain.
JH Observations Note: Since John Herschel observed both NGC 7805 and 7806 on the same date(s), see NGC 7805 for an explanation of why there are two dates listed for his observation of NGC 7806.
Physical Information: NGC 7806 is interacting with NGC 7805 (which see for images), with which it forms Arp 112, so they must be at the same distance from us (as discussed in the entry for NGC 7805, about 215 million light-years away). Given that and its apparent size of about 0.7 by 0.3 arcmin for the central galaxy and about 1.5 by 0.75 arcmin for its extended arms, NGC 7806's central region is about 45 to 50 thousand light-years across, while its extended arms span about 90 to 95 thousand light-years. Group Membership: The pair of galaxies comprising Arp 112 are listed as members of the NGC 7831 Group, along with NGC 7819, 7836 and more than a dozen other galaxies.
Use By The Arp Atlas: NGC 7805 and 7806 are used by the Arp Atlas of Peculiar Galaxies as an example of an elliptical galaxy (NGC 7805) repelling spiral arms (the northeastern arm of NGC 7806), without any supplementary note. (On the page showing Arp's photo the image has North on the bottom, so it is reversed from the images shown in the entry for NGC 7805, which see.)

Physical Information: None of the standard databases say much about this object, but its distorted shape is almost certainly due to a gravitational interaction with its larger neighbors, so it is probably at the same distance from us (about 215 million light-years). Presuming that, its apparent size of about 0.7 by 0.15 arcmin (from the image below) means that PGC 111 spans about 40 to 45 thousand light-years.
Why PGC 111 Is Almost Certainly Not Part Of Arp 112: As noted in the entries for NGC 7805 and 7806, Arp 112 is an example of an elliptical galaxy (NGC 7805) "repelling" a spiral arm in its neighbor (the northeastern arm of NGC 7806). That would make Arp 112 only the two large galaxies; but since PGC 111 is almost certainly a companion of and distorted by those galaxies, it is equally certainly part of the same system, and most images of Arp 112 show PGC 111, even though it isn't part of the Arp object. In fact, it is shown in the original Arp Atlas image, and since the image is centered on NGC 7806, instead of in-between NGC 7805 and 7806, it is conceivable that Arp meant to include it in the term "repelling a spiral arm". However, in the absence of any note in the Arp Atlas about exactly what Arp meant, it seems best to presume (as stated above) that only the two major galaxies should be thought of as Arp 112.

Historical Identification: Per Dreyer, NGC 7807 (Ormond Stone list I (#271), 1860 RA 23 54 30, NPD 109 33.0) is "extremely faint, pretty small, irregular figure." The second IC lists a corrected position (per Howe) of RA 23 53 16, NPD 109 37.2. Howe's position precesses to RA 00 00 27.2, Dec -18 50 26, within 0.2 arcmin of the center of the galaxy listed above, so the identification is certain.
Position Note: Per Gottlieb and Corwin, the RA in the ESO catalogue is too small due to a typographical error (the digits for the seconds of time were reversed). SGC and NGC 2000.0 copied the ESO position, so they have the same error.
Physical Information: Based on a recessional velocity relative to the Cosmic Background Radiation of 7330 km/sec (and H₀ = 70 km/sec/Mpc), a straightforward calculation indicates that NGC 7807 is about 340 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 330 million light-years away at the time the light by which we see it was emitted, about 335 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 0.7 by 0.45 arcmin (from the images below), the galaxy is about 65 to 70 thousand light-years across.

Historical Identification: Per Dreyer, NGC 7808 (Muller list I (#272), 1860 RA 23 54 30, NPD 101 31.0) is "extremely faint, very small, round, stellar nucleus, 8.5 magnitude star south-preceding (to southwest) 3 arcmin." The second IC lists a corrected RA (per Howe) of 23 56 23. The corrected position precesses to RA 00 03 33.3, Dec -10 44 14, only 0.5 arcmin northeast of the galaxy listed above, and the star to its southwest makes the identification certain.
Discovery Note: Muller's position was 2 minutes of time too far to the west, but as noted by Corwin, the star to the southwest of the galaxy made it possible for Howe to find the galaxy and provide its correct position.
Misidentification Note: Per Gottlieb, ESO misidentifies this object as "Conc(entration) of stars only".
Physical Information: Based on a recessional velocity relative to the Cosmic Background Radiation of 8520 km/sec (and H₀ = 70 km/sec/Mpc), a straightforward calculation indicates that NGC 7808 is about 395 to 400 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 380 to 385 million light-years away at the time the light by which we see it was emitted, about 390 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 1.1 by 1.1 arcmin (from the images below), the galaxy is about 120 to 125 thousand light-years across. NGC 7808 is listed as a Seyfert galaxy (type Sy 1).

Physical Information: Based on a recessional velocity relative to the Cosmic Background Radiation of about 8595 km/sec (and H₀ = 70 km/sec/Mpc), a straightforward calculation indicates that PGC 219 is about 400 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 385 to 390 million light-years away at the time the light by which we see it was emitted, about 390 to 395 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 0.68 by 0.18 arcmin (from the image below), the galaxy is about 75 thousand light-years across.
Possible Companionship With NGC 7808: Although the recessional velocity of PGC 219 is almost 200 km/sec less than that of NGC 7808, such "peculiar velocities" (random motions of galaxies relative to their neighbors) are not uncommon. So although it is possible that PGC 219 is a slightly foreground object and not an actual companion of NGC 7808, it is also possible that they are closer together than their calculated distances, and a gravitationally bound system.
Classification Note: NED lists this as type S0, but its color and extended shape are more suggestive of an edge-on spiral, and LEDA lists it as type Sb?. I have chosen the LEDA classification as more likely to be correct, and added "sp" ("spindle") to indicate that if a spiral, it is seen edge-on.

Historical Identification: Per Dreyer, NGC 7809 (= GC 6236, Marth #593, 1860 RA 23 54 56, NPD 87 51) is "extremely faint, very small." The position precesses to RA 00 02 06.2, Dec +02 55 46, one arcmin southwest of the galaxy listed above and there is nothing else nearby, so the identification seems certain.
Physical Information: Based on a recessional velocity of 19,195 km/sec, a straightforward calculation indicates that NGC 7809 is about 895 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 830 million light-years away at the time the light by which we see it was emitted, about 855 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 0.62 by 0.57 arcmin (from the images below, the galaxy is about 150 thousand light-years across.

Historical Identification: Per Dreyer, NGC 7810 (= GC 5044 = JH 2296 = (WH III 984), H. MS, 1860 RA 23 55 09, NPD 77 48.3) is "pretty faint, stellar, 2 stars north-preceding (to northwest) in line." The position precesses to RA 00 02 19.1, Dec +12 58 29, within 0.2 arcmin of the center of the galaxy listed above, and the description of the nearby starfield makes the identification certain.
Discovery Information: This object, though observed by William Herschel, was not published in any of his catalogues because he was uncertain about whether it had any nebulosity, and decided it was not worth publishing ("stellar" being so accurate for visual observation that his decision was not unreasonable). "H. MS" refers to its being recorded in Herschel's handwritten papers ("manuscripts"), with a position only 1.5 arcmin too far north, so after observing it himself, John Herschel assigned it the designation WH III 984, based on where it would have been placed in his father's catalogues if it had been published (thereby leading to Dreyer's placing that note in parentheses). Gottlieb notes that Swift independently found the galaxy, listing it as number 99 in his list VI, with a position 16 seconds of time too far west, but with a perfect description of the field of view, so there is no doubting what he saw.
Physical Information: Based on a recessional velocity relative to the Cosmic Microwave Background radiation of 5125 km/sec (and H₀ = 70 km/sec/Mpc), NGC 7810 is about 235 to 240 million light-years away. Given that and its apparent size of about 0.65 by 0.25 arcmin for the main galaxy and about 0.9 by 0.6 arcmin for an extended halo (from the images below), the galaxy is about 45 thousand light-years across, while the halo spans about 60 to 65 thousand light-years. The galaxy is the namesake of the NGC 7810 Group of galaxies, which also includes NGC 7803 and Hickson Compact Group 100.
Classification Note: Both HyperLEDA and NED list this as a lenticular (type S0) galaxy, but as the images below show, it is actually a nearly edge-on spiral. I have added a question mark to the suggestion that it has both spiral arms and a central ring because the aspect makes it hard to be sure what it actually looks like.

Historical Identification: Per Dreyer, NGC 7811 (= GC 6237, Marth #594, 1860 RA 23 55 15, NPD 87 26) is "very faint, small, round, stellar." The position precesses to RA 00 02 25.2, Dec +03 20 47, about 0.4 arcmin southwest of the center of the galaxy listed above, barely beyond its outline, and there is nothing else nearby, so the identification is certain.
Physical Information: Based on a recessional velocity relative to the Cosmic Background Radiation of 7290 km/sec (and H₀ = 70 km/sec/Mpc), a straightforward calculation indicates that NGC 7811 is about 340 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 330 million light-years away at the time the light by which we see it was emitted, about 335 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 0.44 by 0.42 arcmin (from the images below), the galaxy is about 40 to 45 thousand light-years across. NGC 7811 is a Seyfert galaxy (type Sy 1.5).
Classification Note: Based on old images, HyperLEDA and NED list this as a compact irregular galaxy (cIm); but the images below clearly show that it is a spiral galaxy.

Historical Identification: Per Dreyer, NGC 7812 (= GC 5045 = JH 4010, 1860 RA 23 55 43, NPD 125 01.6) is "very faint, small, round, among stars." The position precesses to RA 00 02 53.7, Dec -34 14 49, only about 0.6 arcmin south of the galaxy listed above and there is nothing nearby, so the identification is certain.
Physical Information: Based on a recessional velocity relative to the Cosmic Background Radiation of 6535 km/sec (and H₀ = 70 km/sec/Mpc), a straightforward calculation indicates that NGC 7812 is about 305 million light-years away, in reasonable agreement with redshift-independent distance estimates of about 270 to 295 million light-years. 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 just over 295 million light-years away at the time the light by which we see it was emitted, about 300 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 1.25 by 0.85 arcmin (from the images below), the galaxy is about 105 to 110 thousand light-years across.

Historical Identification: Per Dreyer, NGC 7813 (Muller list II (#476), 1860 RA 23 56 04, NPD 102 46.0) is "extremely faint, very small, extended 80°, 8.5 magnitude star following (to east) 38 seconds of time, 9th magnitude star north-preceding (to northwest) 40 seconds of time." Muller's position precesses to RA 00 03 14.4, Dec -11 59 14, but there is nothing there, and the only 8th magnitude star in the region (magnitude 8.1 HD 225088) is practically on top of the supposed position, instead of tens of seconds of time away.

A Possible "Solution": Perhaps Muller accidentally used the RA for the 8th magnitude star (he would have had to measure that to conclude that it was 38 seconds of time to the east of his supposed nebula), and the correct RA for his observation was around 38 seconds of time to the west of the star, or at (1860) RA 23 55 22. In that case his position would precess to RA 00 02 32.5, Dec -11 59 14. As shown in the 36 arcmin wide DSS image immediately below, that position is between the magnitude 8.1 star to its east, and a magnitude 9.0 star (the spectroscopic double HD 224973) to its west-northwest (though since it is closer than 40 seconds of time, perhaps a position a little to the east of center of the two stars, or about RA 00 02 49, Dec -11 59 14, as shown near the start of this entry, would be the best estimate of Muller's "corrected" position). Unfortunately, there is nothing there nor anywhere near there either, but any position near that would more or less agree with Muller's description of the star field; so if we accept his description, the most likely answer to "what is NGC 7813?" is "nonexistent."

(Mis)identification as IC 5384: (1) Historical Background: When Howe made an attempt to observe NGC 7813 in 1899 he couldn't find anything in the region except for an object well to the east of Muller's position (and well to the east of his "8.5 magnitude star"). In a note at the end of the IC2, Dreyer wrote "Howe only found a nebulosity in RA 23 57 00, NPD 102 45.8, extended 160°, 8.5 magnitude star 49 seconds of time preceding (to the west), two 9th magnitude stars 8 arcmin north (= IC 5384)." The fact that the description of the star field is completely at odds with Muller's description is undoubtedly what led Dreyer to assign an IC designation to Howe's object. When Howe re-observed a previously discovered object, but at an incorrect position, if he thought that the object he saw was the original one, he published a corrected position, and Dreyer simply noted the correction in the notes to whichever of the NGC/IC volumes he was currently working on. But in this case, given the difference in the star fields, Dreyer probably thought that the two observations were of different objects, so he gave Howe credit for a new discovery. Unfortunately, in his description of IC 5843 (which see) he added (? = 7813) to the end of its catalog description. So despite Dreyer's probable doubt about the identity of the two entries, he hedged his bet with that query.
(2) Modern Blunders: In the 1970's the notoriously infamous RNGC routinely assigned NGC objects that couldn't be identified to whatever galaxy happened to be nearest, regardless of whether that was a reasonable thing to do; and since IC 5843 is the only thing near Muller's position for NGC 7813, the RNGC "confirmed" Dreyer's uncertain query. As a result, modern catalogs such as NED and HyperLEDA treat the two designations as identical, without bothering to mention that there is considerable uncertainty about that. It is that neglect (and almost certain error) that led to the title of this entry being a warning denying the possibility that NGC 7813 and IC 5843 are the same. (Below, an 18 arcmin wide DSS image [centered at RA 00 03 42, Dec -11 59 10] showing Muller's position and Howe's IC 5384. The two brightest stars at top left and the brighter one at far right agree with Howe's description, but not Muller's.)

Final Comments: Corwin notes the problem with the description of the star fields, but supposes that the description of the nebula itself, though also differing, is close enough to assume that the NGC and IC objects are the same. Gottlieb is more cautious about equating the NGC and IC entries, writing that the two "are perhaps identical... but not with certainty." As the wide-field image above shows, Muller's declination (NPD) is a reasonable fit for the IC object, so ignoring what I already wrote , it is possible that the NGC and IC objects are the same, and Muller bungled the RA and so badly mangled the description of the star field that it only seems inconceivable that NGC 7813 is IC 5384. Still, although a very wide stretch of the imagination might approve a duplicate entry with the IC object, my opinion is that Dreyer should have written that NGC 7813 was to be struck out, and only the IC designation used for that galaxy.
Physical Information: Given the high probability that NGC 7813 is nonexistent, see IC 5384 for anything else.

Historical Identification: Per Dreyer, NGC 7814 (= GC 5046 = JH 2297 = WH II 240, 1860 RA 23 56 05, NPD 74 38.9) is "considerably bright, considerably large, extended, very gradually brighter middle." The position precesses to RA 00 03 15.2, Dec +16 07 53, about 0.8 arcmin south of the center of the galaxy listed above and within its southern outline, so the identification is certain. NGC 7814 is sometimes called the Little Sombrero, because of its resemblance to M104.
Description Note: Mitchell's observation was done long after the publication of the GC, and did not affect Dreyer's description in the NGC, but since he was using the 72-inch telescope at Birr Castle, led to a description and sketch which would be accurate descriptions of modern photographs.
Physical Information: Based on a recessional velocity relative to the Cosmic Background Radiation of 695 km/sec (and H₀ = 70 km/sec/Mpc), NGC 7814 is about 30 to 35 million light-years away, in reasonable agreement with redshift-independent distances of about 35 to 70 million light-years. Using a distance of about 35 million light-years and its apparent size of about 6.9 by 2.1 arcmin (from the images below), the galaxy is about 70 thousand light-years across. The galaxy is the namesake of the NGC 7814 Group, which also contains NGC 14, PGC 38, 332 and 889.
Classification Note "sp" = "spindle", which means that the galaxy is edge-on to our line of sight.

Historical Identification: Per Dreyer, NGC 7814 (= GC 6238, Schultz (Nova XII), 1860 RA 23 56 15, NPD 70 04.5) is "faint, small, a little extended, h 2300 north-following (to northeast)," (JH) 2300 being NGC 7817. The position precesses to RA 00 03 25.2, Dec +20 42 17, within 0.1 arcmin of the star listed above, and NGC 7817 is to the northeast, so the identification is certain.
Observational Notes: Although Bigourdan's position for NGC 7815 falls on the star listed above, he also mentions the faint star 1.3 arcmin to the east of that one in his description of the NGC object. Per Corwin, Schultz's observation(s) of this object were done on damp nights, and that and glare from the 7th magnitude star to the south may have helped Schultz to think that he had observed a nebulous object; but since most of his "novae" were single or double stars, he was probably just in the habit of looking for more than he could really see.

Historical Identification: Per Dreyer, NGC 7816 (= GC 5047 = GC 5048 = JH 2298 = JH 2299 = WH III 436, 1860 RA 23 56 39, NPD 83 18.1) is "very faint, pretty large, round, gradually brighter middle." The position precesses to RA 00 03 49.3, Dec +07 28 41, almost dead center on the galaxy listed above, so the identification is certain.
Discovery Notes: Gottlieb notes that John Herschel may have observed this on both Aug 15 (his #2298) and 16 (his #2299), but since his declinations differed by 7.5 arcmin Herschel assumed that he had observed two different objects (the GC states that the position for JH 2298 is very uncertain, and though its RA matches NGC 7816, its NPD matches NGC 7818). Auwers equated III 436 (definitely = NGC 7816) and JH 2298, listing its position as (1830) RA 23 55 09, Dec +06 31 (= J2000 RA 00 03 51.4, Dec +07 27 48), which lies on the southeastern "edge" of NGC 7816, and would agree with Dreyer's treating both JH 2298 and 2299 as observations of NGC 7816. There is no doubt that JH 2299 is NGC 7816 (hence my use of its date for JH's observation), but given JH's doubts about his observations, his earlier observation may have been a poorly measured observation of NGC 7818, and therefore not for the same object as the latter observation. For that reason, although JH may have observed NGC 7816 on Aug 15, it is only certain that he observed it on Aug 16, as shown above.
Physical Information: Based on a recessional velocity relative to the Cosmic Microwave Background radiation of 4880 km/sec (and H₀ = 70 km/sec/Mpc), NGC 7816 is about 225 to 230 million light-years away, much farther than a single redshift-independent distance estimates of about 110 to 115 million light-years. Since the recessional velocity is so large it is a far better indicator of the distance than the redshift-independent estimate, so 225 million light-years is probably the best estimate of the distance. Given that and its apparent size of about 2.3 by 2.25 arcmin for the main galaxy and about 2.9 by 2.8 arcmin counting a very faint partial ring running clockwise from the western to the southeastern side of the galaxy (apparent size and description obtained from the images below), the main galaxy is about 150 thousand light-years across, and with the outer ring it spans about 190 thousand light-years.
Classification Note: The galaxy has a clearly defined central ring barely attached to the innermost spiral arms (hence rs) and an unusually bright nucleus; so even aside from its size, it is an impressive object.

Historical Identification: Per Dreyer, NGC 7817 (= GC 5049 = JH 2300 = WH II 227, 1860 RA 23 56 49, NPD 70 01.8) is "pretty faint, considerably large, much extended 45°±, a little brighter middle." The position precesses to RA 00 03 59.4, Dec +20 44 59, only 0.2 arcmin east of the nucleus of the galaxy listed above and well within its outline, so the identification is certain.
Physical Information: Based on a recessional velocity relative to the Cosmic Microwave Background radiation of about 1960 km/sec (and H₀ = 70 km/sec/Mpc), NGC 7817 is about 90 million light-years away, in good agreement with redshift-independent distance estimates of about 65 to 100 million light-years. Given that and its 2.4 by 0.55 arcmin apparent size (from the images below), the galaxy is about 60 to 65 thousand light-years across. NGC 7817 is listed as a pair with NGC 7798, with a probable separation of about 1.7 million light-years (closer than our galaxy and the Andromeda galaxy).

Historical Identification: Per Dreyer, NGC 7818 (Swift list VI (#100), 1860 RA 23 56 59, NPD 83 22.8) is "most extremely faint, pretty small, very difficult, south-following (southeast of) h 2298," (JH) 2298 being NGC 7816. The position precesses to RA 00 04 09.3, Dec +07 23 59, about 1.2 arcmin north of the galaxy listed above, there is nothing else nearby, and its position relative to NGC 7816 makes the identification certain.
Discovery Note: See NGC 7816 for a discussion of the possibility that JH's #2298 may have been a poorly measured observation of NGC 7818. But even if it was, the continuing confusion about which object it corresponds to means that Swift's observation was an independent discovery, and perhaps the only observation prior to the publication of the NGC.
Physical Information:Based on a recessional velocity relative to the Cosmic Microwave Background radiation of 5840 km/sec (and H₀ = 70 km/sec/Mpc), NGC 7818 is about 270 to 275 million light-years away. Given that and its apparent size of about 0.85 by 0.62 arcmin (from the images below), the galaxy is about 65 to 70 thousand light-years across. NED lists NGC 7818 as a disturbed member of a pair, presumably with NGC 7816, which is only a few arcmin away and also listed as a pair member; but given the roughly 1000 km/sec difference in their recessional velocities, NGC 7816 must be nearly 50 million light-years closer to us, so the two galaxies are only an optical double.

Historical Identification: Per Dreyer, NGC 7819 (= GC 6239, Copeland using Lord Rosse's 72-inch telescope, 1860 RA 23 57 11, NPD 59 18.3) is "extremely faint, large." The position precesses to RA 00 04 21.7, Dec +31 28 28, only 0.7 arcmin west of the center of the galaxy listed above and within its outline, so the identification is certain.
Discovery Note: Copeland made two measurements of the position of this object, placing it just under 3 minutes of time to the east of GC 5042 (NGC 7805). Dreyer also made two observations of an object 3 minutes of time to the east of GC 5042, duplicating Copeland's observation, other than adding "diffused nebula". Although published in the records for Birr Castle, Dreyer must not have thought it worth mentioning his own observations in the NGC.
Physical Information: Based on a recessional velocity relative to the Cosmic Microwave Background radiation of 4625 km/sec (and H₀ = 70 km/sec/Mpc), NGC 7819 is about 215 million light-years away, much farther than redshift-independent distance estimates of about 110 to 135 million light-years. For such a large difference in the estimated distances, "peculiar velocities" (random motions of a galaxy relative to its neighbors) cannot explain the difference, so the 215 million light-year estimate must be given preference. Using that and its apparent size of about 1.6 by 0.95 arcmin (from the images below), NGC 7819 is about 100 thousand light-years across. The galaxy is listed as a member of the NGC 7831 Group, along with NGC 7805, 7806, 7836 and more than a dozen other galaxies.

Historical Identification: Per Dreyer, NGC 7820 (= GC 5050 = JH 2301, 1860 RA 23 57 20, NPD 85 34.8) is "pretty faint, very small, very suddenly much brighter middle, 14th magnitude star south-preceding (to southwest)." The position precesses to RA 00 04 30.3, Dec +05 11 59, almost dead center on the galaxy listed above, so the identification is certain.
Physical Information: Based on a recessional velocity relative to the Cosmic Microwave Background radiation of about 2680 km/sec (and H₀ = 70 km/sec/Mpc), NGC 7820 is about 125 million light-years away. Given that and its apparent size of about 1.35 by 0.5 arcmin (from the images below), the galaxy is about 50 thousand light-years across.

Historical Identification: Per Dreyer, NGC 7821 (Ormond Stone list I (#273), 1860 RA 23 57 30, NPD 107 16.0) is "very faint, pretty small, irregular figure, gradually a little brighter middle." The first IC lists a corrected RA (per Ormond Stone) of 23 58 07. The corrected position precesses to RA 00 05 16.9, Dec -16 29 13, only 0.6 arcmin south of the galaxy listed above, and there is nothing else nearby, so the identification is certain.
Physical Information: Based on a recessional velocity relative to the Cosmic Background Radiation of 7080 km/sec (and H₀ = 70 km/sec/Mpc), a straightforward calculation indicates that NGC 7821 is about 330 million light-years away, in reasonable agreement with redshift-independent distance estimates of about 280 to 325 million light-years. 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 320 million light-years away at the time the light by which we see it was emitted, about 325 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 1.2 by 0.4 arcmin (from the images below), the galaxy is about 110 to 115 thousand light-years across.
Classification Note: "sp" = "spindle" means that the galaxy is seen nearly edge-on.

Historical Identification: Per Dreyer, NGC 7822 (= GC 5051 = JH 2302, 1860 RA 23 57 33, NPD 22 06.3) is "a remarkable object, most extremely faint, most extremely large." (An end-note in the NGC states "Not seen at Birr Castle in two observations. It is, however, far north of the Zenith, and the speculum may have tilted." Despite the uncertainty suggested by that note, Herschel did see something that exactly fits his description, the only question being what part of his "most extremely large" nebula should be listed as NGC 7822.) The second Index Catalog adds (per Roberts, M.N. lxiii, p. 301) "40 arcmin diameter, many stars involved." The position precesses to RA 00 04 45.7, Dec +68 40 28, which is a degree and a half to the north of the central part of the nebula listed above, and has led to much confusion as to what part of the nebula Herschel saw. As a result, many catalogs and websites list the bright central region as Cederblad 214B, and the faint wing to its north as NGC 7822. However, per Corwin, although there may be some confusion about what Herschel saw, there is no doubt that Roberts' measurements were of the bright center, and that is what he and Dreyer presumed was Herschel's object. So whatever Herschel saw, the central part of the nebula has been considered to be NGC 7822 for more than a century.
Physical Information: NGC 7822 is a large, complex emission nebula, filled with hot young stars recently formed from and heating its gases, and partially obscured by dark lanes of gas and dust lying between us and the brighter emission region. The emission nebula covers at least 3 degrees, which at its distance of nearly 3000 light-years makes it 150 light-years across. The loose cluster (or association) of stars near its center contains about 40 O and B stars, of which type O7 is the "earliest", or hottest. This implies an age of 5 to 6 million years for the association.

Historical Identification: Per Dreyer, NGC 7823 (= GC 5052 = JH 4011, 1860 RA 23 57 35, NPD 152 50.7) is "faint, small, round, gradually brighter middle." The position precesses to RA 00 04 43.5, Dec -62 03 55, only 0.6 arcmin southwest of the center of the galaxy listed above and within its outline, so the identification is certain.
Physical Information: Based on a recessional velocity relative to the Cosmic Microwave Background radiation of 4410 km/sec (and H₀ = 70 km/sec/Mpc), NGC 7823 is about 205 million light-years away. Given that and its apparent size of about 0.73 by 0.7 arcmin for the central galaxy and about 1.3 by 1.15 arcmin for the extended halo (from the images below), the main galaxy is about 40 to 45 thousand light-years across, and the halo spans about 75 to 80 thousand light-years.
Classification Note: DSS images of the region provide only a rough indication of what kind of galaxy this is (listed as SB in some references, and SA in others). A 2MASS image of radio emission shows no sign of a bar in the central region and DESI Legacy images, unless processed by an expert, grossly overexpose the central regions, giving the impression of a type SAa galaxy with an enormous nucleus, small spiral arms more like those of type Sc, and an extended halo. If that halo appeared to be connected to the spiral arms the galaxy would probably be classified as (R)S(something), but since it is not, the best way to handle the halo is probably to just add "pec".

Historical Identification: Per Dreyer, NGC 7824 (= GC 5053 = JH 2303, 1860 RA 23 57 54, NPD 83 51.5) is "pretty faint, small, round, 10th magnitude star north-preceding (to northwest)." The position precesses to RA 00 05 04.4, Dec +06 55 17, only 0.5 arcmin west of the center of the galaxy listed above and within its outline, so the identification is certain.
Physical Information: Based on a recessional velocity relative to the Cosmic Background Radiation of about 5775 km/sec (and H₀ = 70 km/sec/Mpc), NGC 7824 is about 265 to 270 million light-years away, in reasonable agreement with redshift-independent distance estimates of about 260 to 345 million light-years. Given that and its apparent size of about 1.65 by 0.95 arcmin (from the images below), the galaxy is about 130 thousand light-years across. The galaxy is listed as a member of a pair with 9 arcmin distant PGC 366, and their apparent separation and estimated distances are close enough that there is a good chance that they are a gravitationally bound system. If at the same distance from us, the two are about 750 thousand light-years apart, but of course one or the other could be a two or three million light-years closer to us than the other one (that is, about as far apart as our galaxy and the Andromeda galaxy) and still be a pair.

Physical Information: Based on a recessional velocity relative to the Cosmic Background Radiation of about 5930 km/sec (and H₀ = 70 km/sec/Mpc), PGC 366 is about 275 million light-years away, in reasonable agreement with redshift-independent distance estimates of about 275 to 310 million light-years. Given that and its apparent size of about 1.55 by 0.45 arcmin (from the images below), the galaxy is about 125 thousand light-years across. The galaxy is listed as a member of a pair with 9 arcmin distant NGC 7824, and their apparent separation and estimated distances are close enough that there is a good chance that they are a gravitationally bound system. If at the same distance from us, the two are about 750 thousand light-years apart, but of course one or the other could be two or three million light-years closer to us than the other one (that is, about as far apart as our galaxy and the Andromeda galaxy) and still be a pair.

Historical Identification: Per Dreyer, NGC 7825 (= GC 5054 = JH 2304, 1860 RA 23 57 58, NPD 85 33.9) is "very faint, small, gradually brighter middle." The position precesses to RA 00 05 08.4, Dec +05 12 53, only 0.8 arcmin northeast of the galaxy listed above, and there is nothing else nearby, so the identification is certain.
ID Misidentifications: Due to errors in the UGC, MCG and RC3, there are/were several misidentifications of NGC 7825, NGC 7827 and PGC 376 in various catalogues, as noted by Gottlieb, Corwin and in the NED. This led to errors in earlier versions of the corresponding entries on this page, but those errors have now been corrected.
Physical Information: Based on a recessional velocity relative to the Cosmic Background Radiation of 7695 km/sec (and H₀ = 70 km/sec/Mpc), a straightforward calculation indicates that NGC 7825 is about 355 to 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 345 to 350 million light-years away at the time the light by which we see it was emitted, about 350 to 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 0.75 by 0.15 arcmin (from the images below), the galaxy is about 75 thousand light-years across.

(Mis)identification Note: As noted in the entries for NGC 7825 and 7827, various catalogues made (and some still make) a "hash" of the three galaxies in this region. Per Corwin, MCG mangled the identification of the galaxies, UGC 37 was misidentified as NGC 7825, and as a result the original PGC and RC3 made the same error. Fortunately, as an online catalog, HyperLEDA was able to correct the Principle Galaxy Catalogue error, so PGC 376 is no longer listed as an NGC object in that catalog.
Physical Information: Based on a recessional velocity relative to the Cosmic Microwave Background radiation of 5265 km/sec (and H₀ = 70 km/sec/Mpc), PGC 376 is about 245 million light-years away. Given that and its apparent size of about 1.2 by 0.45 arcmin (from the images below), the galaxy is about 90 thousand light-years across (counting from the ends of the extended spiral arms). As noted in the introduction to this entry, PGC 376 is probably a companion of NGC 7827.

Historical Identification: Per Dreyer, NGC 7826 (= GC 5055 = JH 2305 = WH VIII 29, 1860 RA 23 58 02, NPD 111 29.6) is "a cluster, very poor, very little compressed." Corwin quotes John Herschel's GC ("A triangular group of about a dozen stars"), then adds that the stars are pretty bright, and cover a region about 9 by 13 arcmin with its apex to the south. For such loose clusters, different catalogs list slightly different positions, as the center can't be accurately defined. Corwin's position (listed above) lies a little east-northeast of the pair of 9th-magnitude stars near the center of the image below. John Herschel's position precesses to RA 00 05 11.8, Dec -20 42 49, the position of the western member of the pair, so the general identification of the group is certain. Per Gottlieb, the proper motions of the stars rule out their being an actual cluster; they are merely stars whose random positions happen to make them look like a group (hence, an asterism).
Identification Note: Some discussions of this group include the double star shown near top left in the wide-field image below, which leads to the position shown in the description line. William Herschel's position suggests that the double should be included in the NGC object, but John Herschel's position would probably omit it. Both definitions fit "A triangular group", the wider one being an equilateral triangle including the eastern double, and the narrower one an acute triangle narrower at the south (bottom); so which identification of the group is correct is not obvious. But since NGC 7826 isn't a physical group at all, it probably makes no difference which choice is made, which is why I have shown both of them.

Historical Identification: Per Dreyer, NGC 7827 (= GC 5056 = JH 2306, 1860 RA 23 58 18, NPD 85 33.5) is "very faint, small, round, 12th or 13th magnitude star north-following (to northeast)." The position precesses to RA 00 05 28.4, Dec +05 13 17, only 0.2 arcmin east of the center of the galaxy listed above and well within its outline, so the identification is certain.
ID Misidentifications: Due to errors in the UGC, MCG and RC3, there are/were several misidentifications of NGC 7825, NGC 7827 and PGC 376 in various catalogues, as noted by Gottlieb, Corwin and in the NED. This led to errors in earlier versions of the corresponding entries on this page, but those errors have now been corrected.
Physical Information: Based on a recessional velocity of 5295 km/sec, NGC 7827 is about 245 million light-years distant. Given that and its 1.2 by 0.9? arcmin apparent size, it is about 85 thousand light-years across.
 NED lists NGC 7827 as the namesake of the NGC 7827 Group, since it is the only NGC object in the group (WBL 006), which supposedly has three members; however, the recessional velocity listed for that group is much greater than the recessional velocity of NGC 7827, and none of the other members of the "poor" group are mentioned, so whether that designation is deserved seems uncertain at best. The only thing certain as of this writing is that PGC 376, which is often misidentified as NGC 7825, is probably a companion of NGC 7827.

Historical Identification: Per Dreyer, NGC 7828 (Leavenworth list II (#274), 1860 RA 23 58 46, NPD 104 11.0) is "extremely faint, small, extended 130°, suddenly brighter middle and nucleus, 15th magnitude star south-following (to southeast), NGC 7829 20 arcsec distant at position angle 100°." The second IC lists a corrected RA (per Howe) of 23 59 17. The corrected position precesses to RA 00 06 26.7, Dec -13 24 14, about 0.7 arcmin to the north of the galaxy listed above, close enough to be certain of the identification even without the accurate description given for the relative position of NGC 7828 and its companion, NGC 7829. Both galaxies are distorted by the gravitational (and possibly collisional?) effects of their interaction, leading to the pair's inclusion in Arp's Atlas of Peculiar Galaxies.
Note To Self: Per Gottlieb, the "ring" has a very unusual distorted appearance. "According to Higdon (1988), this is not a classical ring but possibly the result of stripping of the gaseous disk of a spiral galaxy during the collision with an intergalactic HI cloud. It was rejected as a ring galaxy... by Romano et al."
Physical Information: Based on a recessional velocity of 5730 km/sec, NGC 7828 is about 265 million light-years away (and obviously at the same distance as its companion). Given that and its 0.9 by 0.5? arcmin apparent size, it is about 70 thousand light-years across.
Use By The Arp Atlas: NGC 7828 and 7829 are used by the Arp Atlas of Peculiar Galaxies as an example of material (NGC 7828) emanating from elliptical galaxies (NGC 7829), with no comment about the system. (The image in the Arp Atlas has North on the left, so it is rotated 90 degrees counterclockwise compared to the images on this page.)

Physical Information: Not much is known about this galaxy. Classifications range from fairly standard (SABb) to complex (SB(s) c pec II-III), hence the question mark in the type shown in the description line. The distance and recessional velocity of the galaxy are unknown, so all that can be said about it is that it has an apparent size of about 0.75 by 0.55 arcmin (from the images below).
Usage By The Arp Atlas: PGC 475 is used by the Arp Atlas of Peculiar Galaxies as an example of a spiral galaxy with a small high-surface-brightness companion, but the Atlas does not identify the object, or provide any note about its appearance; all that it contains is an image and the coordinates of the galaxy, and only its Arp number places it in its Atlas category. There is no obvious companion, but there is a small "knot" on the northeastern spiral arm, and that is presumably what Arp took for an elliptical companion.
Database Notes: HyperLEDA does not have an entry for Arp 51, nor does it show that PGC 475 is Arp 51; but a search of the database for that Arp object does bring up the page for PGC 475. A search of NED for Arp 51 brings up a page with that title, identifies it as PGC 475, and adds "M51 Type" and "small, high surface brightness companion on end of arm". As noted in the preceding paragraph, the Arp Atlas doesn't specify where the supposed companion is, but the knot referred to there is near the end of an arm.

Historical Identification: Per Dreyer, NGC 7829 (Leavenworth list II (#275), 1860 RA 23 58 46, NPD 104 11.0) is "extremely faint, extremely small, round (nebulous?), following (eastern) of 2, 20 arcsec from NGC 7828 at position angle 100°," the position angle being measured from 7828. The second IC adds (per Howe) "only a 13th-magnitude star." Since Howe dismissed the object as a star, Dreyer did not bother to list a corrected position for NGC 7829; but since Leavenworth gave the same position for the two galaxies (other than their 20 arcsec separation), any error in the precessed position of NGC 7829 (which would be the same as Howe's corrected position for NGC 7828) is irrelevant, as Leavenworth's correct description of the pair's relative position means that the certain identification of NGC 7828 makes the identification of NGC 7829 equally certain. Most importantly, NGC 7829 is indeed a galaxy, which forms a close pair with NGC 7828. Both galaxies are distorted by the gravitational (and possibly collisional?) effects of their interaction, leading to the pair's inclusion in Arp's Atlas of Peculiar Galaxies.
Physical Information: Based on a recessional velocity of 5715 km/sec, NGC 7829 is about 265 million light-years away (and obviously at the same distance as its companion). Given that and its 0.7 by 0.7? arcmin apparent size, it is about 55 thousand light-years across. (See NGC 7828 for images of the pair and the region near them.)
Use By The Arp Atlas: NGC 7828 and 7829 are used by the Arp Atlas of Peculiar Galaxies as an example of material (NGC 7828) emanating from elliptical galaxies (NGC 7829), with no comment about the system. (The image in the Arp Atlas has North on the left, so it is rotated 90 degrees counterclockwise compared to the images on this page.)

Historical Identification: Per Dreyer, NGC 7830 (= GC 6240, Marth #595, 1860 RA 23 59 01, NPD 82 24) is "extremely faint, nebulous 13th magnitude star." The second IC lists a corrected RA (per Bigourdan) of 23 58 49; but for reasons discussed in the next paragraph, Corwin rejects Bigourdan's observation and supposed correction. The original NGC position precesses to RA 00 06 11.6, Dec +08 22 46, less than 1/4 arcmin nearly due west of the star listed above, as noted in the paragraph below the description is probably the best that Marth could have made, and there is absolutely nothing else anywhere in the region, so the identification is considered certain.
Identification Notes: Corwin's long note starts with a statement that the star and some very faint galaxies near the star were almost certainly too faint for Marth to see, and certainly far fainter than Marth's estimate of magnitude 13. However, he later compared Marth #595 with several other objects discovered by Marth on the same night, in particular NGC 4, which is magnitude 15.5, and concluded that Marth probably could see the star with Lassell's 48-inch telescope, its "neighbors" perhaps giving it the impression of a "nebulous" object, and almost certainly used "13th magnitude" for anything at the limit of his ability to see, so that what Marth saw was almost certainly the object shown above. As for Bigourdan's observation, which differs from Marth's by nearly 2 minutes of time, Corwin states that there is nothing there, and that what Bigourdan thought he saw was certainly not Marth's object, but probably one of Bigourdan's "fausse" (that is, nonexistent) objects. He therefore rejected Bigourdan's position (as noted in the first paragraph of this entry) and the credit given to him by Dreyer.
 In Bigourdan's "Big Book", he listed three observations of NGC 7830 (on Dec 1, 1885, Nov 21, 1897, and Oct 31, 1899). In all three cases he stated that the object is an insignificant nebula or nebulous star; in one he states that there is no other nebulous object in the region; in another that he barely glimpsed the object; and all of his observations disagree with the NGC position. So it might have been reasonable for Dreyer to treat Bigourdan's position as a correction of Marth's position, but even if Bigourdan did see something, it probably wasn't what Marth saw, and Corwin's rejection of Bigourdan's observations is almost certainly correct.
Physical Information: Basically, this object is just a faint star, with a suggestion of nebulosity perhaps caused by extremely distant galaxies too faint for Marth to have seen, none of which have any information available as of this writing.

Historical Identification: Per Dreyer, NGC 7831 (Swift list II (#1), 1860 RA 23 59 06, NPD 58 18.3) is "extremely faint, very small, much extended, very faint star very near." The position precesses to RA 00 06 17.7, Dec +32 28 28, over a minute of time west and 8 arcmin south of the galaxy listed above. But as noted for NGC 6, Swift made the same error for several objects discovered on the same night, so the consistency of the error and his descriptions of the nearby star fields have allowed for correct identification of the objects. Per Corwin, for NGC 7831 Swift noted "bright star south, very faint star very near", the "bright" star presumably being the magnitude 9.5 star about 2 arcmin south of the galaxy, and the "very faint" star being the 15th-magnitude star at its southwestern end. So despite Swift's positional error, the identification seems certain. However, his error did mean that when Bigourdan made a correct measurement of the position it was thought that he had discovered a separate object, whence the duplicate listing.
Physical Information: Based on a recessional velocity of 5075 km/sec, NGC 7831 is about 235 million light-years distant, in good agreement with redshift-independent distance estimates of 205 to 250 million light-years. Given that and its 1.7 by 0.4? arcmin apparent size, it is about 115 thousand light-years across. The galaxy is listed as the namesake of the NGC 7831 Group, which includes NGC 7805, 7806, 7819, 7836 and more than a dozen other galaxies.

Historical Identification: Per Dreyer, NGC 7832 (= GC 5057 = JH 4013 = WH III 190, 1860 RA 23 59 17, NPD 94 29.8) is "very faint, very small, round, very gradually then pretty suddenly much brighter middle, two 9th magnitude stars south-following (to southeast)." The position precesses to RA 00 06 27.1, Dec -03 43 02, only 0.3 arcmin west of the center of the galaxy listed above, so the identification is certain. (For a discussion of the duplicate listing, see IC 5386.)
Physical Information: Based on a recessional velocity of 6250 km/sec, NGC 7832 is about 290 million light-years away. Given that and its apparent size of 1.9 by 1.0? arcmin, it is about 160 thousand light-years across.

Historical Identification: Per Dreyer, NGC 7833 (Bigourdan (#101), 1860 RA 23 59 21, NPD 63 08) is "a cluster, very small, very faint, 2.5 arcmin, nebulous?." The position precesses to RA 00 06 32.5, Dec +27 38 46, dead center on the asterism listed above, so the identification is certain. In modern images the group consists of a few 15th to 16th magnitude stars and PGC 1813988, a galaxy discussed immediately below. However, that galaxy is far too faint for Bigourdan to have seen, so although I have given it an entry, it is not part of NGC 7833.
Discovery Note: As stated in the NGC, Bigourdan claimed B101 was 2.5 arcmin across, and there are five stars within that diameter; but some catalogs use a smaller diameter (about 1.5 arcmin), and as a result, exclude the outermost member of the asterism.

Physical Information: Apparent size 0.15 by 0.15 arcmin?
LEDA B 18.02, I 16.15 -> V 17.0(?); NED 3K Vr 43140 km/sec, z 0.1439035 -> 1705 Mly, 1825 Myr

Historical Identification: Per Dreyer, NGC 7834 (= GC 6241, Marth #596, 1860 RA 23 59 26, NPD 82 24) is "most extremely faint, very small." The position precesses to RA 00 06 36.6, Dec +08 22 46, about 0.7 arcmin north of the galaxy listed above, an error shared with two other galaxies discovered by Marth on the same night, the double nebula NGC 7837 and 7838. The three galaxies are close together, and their relative positions are correct, so the certain identification of the double nebula makes the identification of NGC 7834 equally certain.
Physical Information: Based on a recessional velocity of 5230 km/sec, NGC 7834 is about 245 million light-years distant. Given that and its apparent size of 1.1 by 0.8? arcmin, it is about 80 thousand light-years across.

Historical Identification: Per Dreyer, NGC 7835 (= GC 6242, Marth #597, 1860 RA 23 59 35, NPD 82 21) is "extremely faint, small, round." The position precesses to RA 00 06 45.7, Dec +08 25 46, about a third of an arcmin northwest of the center of the galaxy listed above and barely outside its outline, and there is nothing else nearby, so the identification is certain.
Physical Information: The apparent size of NGC 7835 is 0.55 by 0.25 arcmin; apparently nothing else is available.

Historical Identification: Per Dreyer, NGC 7836 (Swift list II (#2), 1860 RA 23 59 35, NPD 57 50.7) is "extremely faint, very small, round, between 2 stars." The second IC lists a corrected position (per Bigourdan) of RA 00 00 47, NPD 57 42. The corrected position precesses to RA 00 07 59.6, Dec +33 04 46, only 0.5 arcmin northwest of the galaxy listed above, making the identification certain. This is due to Bigourdan's accurate measurement, and not to Swift, whose position was off by more than a minute of time and 8 arcmin of declination. However, as noted by Corwin, this is one of five galaxies (such as NGC 6) discovered by Swift on the same night which all suffered similar errors, so the correct identification would have probably been made eventually, anyway. But it is fortunate that the error was discovered and corrected more than a century ago.
Catalog Note: Per Gottlieb, UGC 65 is not labeled as NGC 7836 in the UGC or CGCG; however, RNGC and PGC (HyperLEDA) have the correct identification.
Physical Information: Based on a recessional velocity of 4905 km/sec, NGC 7836 is about 230 million light-years away, in good agreement with redshift-independent distance estimates of 200 to 350 million light-years. Given that and its apparent size of 0.9 by 0.5? arcmin, it is about 60 thousand light-years across. NGC 7836 is listed as a member of the NGC 7831 Group, along with NGC 7805, 7806, 7819 and more than a dozen other galaxies.

Historical Identification: Per Dreyer, NGC 7837 (= GC 6243, Marth #598, 1860 RA 23 59 41, NPD 82 25) is "extremely faint, preceding (western) of double nebula," the other being NGC 7838. The position precesses to RA 00 06 51.7, Dec +08 21 46, about 0.7 arcmin north of the galaxy listed above, and the reference to a double nebula makes the identification certain.
ID Note: Although LEDA and MCG have separate entries for NGC 7837 and 7838, CGCG treats both galaxies as a single object (Arp 246).
Brightness Note: Steinicke lists this galaxy's visual magnitude as 15.3, while Gottlieb has 14.4; LEDA lists no visual magnitude, while NED has 16, but without any indication of what wavelength range that corresponds to. Hence the question mark after the magnitude in the description line.
Physical Information: Based on a recessional velocity of 11700 km/sec, a straightforward calculation indicates that NGC 7837 is about 545 million light-years away; however, for such a distance it is necessary to take into account the expansion of the Universe during its light's nearly half billion year journey. Doing so shows that the galaxy was about 520 million light-years away at the time the light by which we see it was emitted, about 530 million years ago (the difference between the two numbers being due to the expansion of the intervening space during that time). Given that and its apparent size of 0.4 by 0.2? arcmin, NGC 7837 is about 60 thousand light-years across. The galaxy forms an interacting pair with NGC 7838, and as such is listed as Arp 246.
Use By The Arp Atlas: NGC 7837 and 7838 are used by the Arp Atlas of Peculiar Galaxies as an example of galaxies with an appearance of fission, with the note "May not be physically connected," but without identifying the galaxies except by their position. (The image in the Arp Atlas has North on the right, so it is rotated 90 degrees clockwise compared to the images below.) As it happens, the two galaxies are physically connected and undoubtedly interacting, as noted in the Physical Information above.

Historical Identification: Per Dreyer, NGC 7838 (= GC 6244, Marth #599, 1860 RA 23 59 43, NPD 82 25) is "extremely faint, following (eastern) of double nebula," the other being NGC 7837. The position precesses to RA 00 06 53.7, Dec +08 21 46, about 0.7 arcmin north of the galaxy, and as for NGC 7837 the reference to the double nebula makes the identification certain.
ID Note: Although LEDA and MCG have separate entries for NGC 7837 and 7838, CGCG treats both galaxies as a single object (Arp 246).
Brightness Note: Steinicke lists this galaxy's visual magnitude as 14.6, but Gottlieb has 14.3. As in the case of NGC 7837, LEDA lists no visual magnitude, while NED has 16, but without any indication of what wavelength range that corresponds to. Hence the question mark after the magnitude in the description line.
Physical Information: Based on a recessional velocity of 11595 km/sec, a straightforward calculation indicates that NGC 7838 is about 540 million light-years away. However, for such distances it is necessary to take into account the expansion of the Universe during its light's nearly half billion year journey. Doing so shows that the galaxy was about 520 million light-years away at the time the light by which we see it was emitted, about 530 million years ago (the difference between the two numbers being due to the expansion of the intervening space during that time). Given that and its apparent size of 0.6 by 0.3? arcmin, NGC 7838 is about 90 thousand light-years across. The galaxy forms an interacting pair with NGC 7837 (which see for images), and as such is listed as Arp 246.
Use By The Arp Atlas: NGC 7837 and 7838 are used by the Arp Atlas of Peculiar Galaxies as an example of galaxies with an appearance of fission, with the note "May not be physically connected," but without identifying the galaxies except by their position. (The image in the Arp Atlas has North on the right, so it is rotated 90 degrees clockwise compared to the images shown in the entry for NGC 7837.) As it happens, the two galaxies are physically connected and undoubtedly interacting, as noted in the Physical Information above.

Historical Identification: Per Dreyer, NGC 7839 (Bigourdan (#102), 1860 RA 23 59 50, NPD 63 08.9) is "very faint, pretty small, diffuse, mottled but not resolved." The position precesses to RA 00 07 01.7, Dec +27 37 52, only about 0.5 arcmin southeast of a pair of stars of magnitudes 15.4 and 17.5 (which are listed as NGC 7839 by Steinicke and NED), which is certainly close enough to consider them a reasonable candidate for the NGC identification. However, as shown above and discussed in the next paragraph, there is considerably controversy about whether to include the fainter star in NGC 7839.
Notes About The Dual Identification: The confusion about whether only the brighter star in the "pair" or both stars should be called NGC 7839 is caused by Bigourdan's statement that his #102 was 40 to 50 arcsec in size, with "several points of condensation"; and if those "points" represent some kind of reality, the fact that the fainter star is only 21 arcsec from the brighter one would suggest that the NGC object should be the pair. In fact, Corwin's notes originally stated that although the position precesses "exactly" (?) to the brighter star listed above, he supposed that the fainter star to the south-southwest might have given Bigourdan the impression of a nebulous object, and he therefore included it in the NGC object. However, after taking another look at the pair, Corwin decided that Bigourdan probably couldn't see the fainter star with his telescope, and now writes that NGC 7839 is only the brighter star. Gottlieb also treats only the brighter star as NGC 7839, and though he could see the fainter star with his 24-inch telescope, he doubts that Bigourdan could have seen such a faint star with only a 12-inch refractor. Steinicke's database doesn't have room for comments, but states 2*, so he designates the NGC object as the pair of stars. NED agrees with this "two star" hypothesis, stating ** as the object type (also without any comment), and listing a position between the two stars. My feeling is that since Bigourdan often observed "fausse" (that is, nonexistent) objects by "seeing" more than his telescope could actually show him (as in the case of his non-observation of NGC 7830), although he undoubtedly observed the brighter star in the pair, the rest of his supposedly larger nebulous object does not exist. So although I have presented both the single-star and double-star "identifications", I believe that NGC 7839 is only the brighter star.
Note About Misidentifications: A Wikisky search for NGC 7839 lands almost exactly on the (single) magnitude 14 star 2 arcmin north-northwest of the NGC position. Meanwhile, LEDA misidentifies NGC 7839 as "PGC 529", a "double star" with a position halfway between the pair close to the NGC position, and the 14th magnitude star misidentified by Wikisky; but there is absolutely nothing at the LEDA position, and no way that stars 2 arcmin apart could possibly be described as a "pretty small, not resolved" object, so although there is some disagreement about whether NGC 7839 is the brighter star in the pair listed in the description line or both of those stars, the LEDA and Wikisky identifications are absolute rubbish.

Historical Identification: Per Dreyer, NGC 7840 (= GC 6245, Marth #600, 1860 RA 23 59 56, NPD 82 21) is "extremely faint, small." The position precesses to RA 00 07 06.7, Dec +08 25 46, nearly 3 arcmin north of the galaxy listed above, which is a much larger error than for any of the other galaxies Marth discovered on the same night (NGC 7834, 7835, 7837 and 7838, and NGC 3 and 4); but since everything else in the region is one of the other galaxies Marth discovered on the same night and his #600 cannot be one of them, although the unusually large error in the NPD is puzzling, the identification seems certain.
Physical Information: The apparent size of NGC 7840 is 0.7 by 0.5? arcmin. Gottlieb lists V = 15.5, whence the question mark in the description line.
LEDA ; NED 3K Vr 10905 km/sec, z 0.0363748