The second IC notes "3103 = 3100, per Howe, confirmed by reference to Swift's original observation"; so the apparent identity of the two entries goes back more than a century. Based on recessional velocity of 2640 km/sec, about 115 million light years away. Given that and apparent size of 3.2 by 1.6 arcmins, about 110 thousand light years in diameter.

There is nothing at Swift's recorded position. His description of the object very closely matches that of NGC 3100, discovered by John Herschel half a century earlier, and as a result, the two have been considered the same object for a century. In fact, as noted in the second IC, "3103 = 3100, per Howe, confirmed by reference to Swift's original observation".

NGC 3109 is the largest member of the Sextans Group, a scattering of small galaxies only a few million light years away. Opinion is divided as to whether the Sextans Group is gravitationally bound to our Local Group of galaxies, or is the nearest separate cluster of galaxies. NGC 3109's recessional velocity is only 405 km/sec, which is too small in comparison to peculiar (non-Hubble-expansion) velocities to be a reliable indicator of its distance. An estimate of its distance based on its recessional velocity would be about 18 million light years, much further than redshift-independent distance estimates of 3.3 to 5.9 million light years, so its peculiar velocity is indeed substantially larger than Universal expansion effects. Assuming a distance of about 4.5 million light years, NGC 3109's apparent size of 20 by 4 arcmin implies that it is about 25 thousand light years across. Originally classified as an irregular galaxy, it now seems likely that it is actually a dwarf spiral seen at an angle which makes its spiral structure difficult to detect, as it appears to have a halo and disk structure typical of spiral galaxies. It is relatively close to the Antlia dwarf (another member of the Sextans Group), and is believed to be tidally interacting with it, in the same way that our galaxy interacts with its companions.

The faint star is the one that created the nebula, not the bright one.

The second IC lists a corrected NPD (per Howe) of 101 53.6

The second IC adds "Not round but much extended, according to Swift. λ Hydrae is to the northwest".