Harold Corwin

IC 1572 is one of Bigourdan's imaginary nebulae. He has only one estimated position of it one night in 1888. There is no problem with his reduction of his position angle and distance to the comparison star (the same star he used for his first observations of NGC 213, which is just where he says it is) -- but there is nothing, not even a faint star, at his reduced position. I expect he was pushing his optics again.

He looked for the object again nine years later in 1897, but did not measure it. This second observation may refer to another object as he says, "Stellar object, seen a little preceding NGC 213." (I can't come up with a reasonable candidate for this object, either.) His first observation puts it 1.5 seconds following N213 and 14 arcmin south. So, even if the first object is a "fausse image", it is probably a different one than this second.

In any case, IC 1572 is lost.

In October 2016, Courtney Seligman suggested that Bigourdan's declination offset bears the wrong sign. If it is +6' 58", then his estimated position falls close to the star superposed on NGC 213. However, as Courtney also points out, the fact that the star is so close to the NGC galaxy suggests that if this really were Bigourdan's "nova", then he (Bigourdan) would have said so. Another problem with the idea is that Bigourdan explicitly mentions the superposed star in his observation of NGC 213 on the same night that he "saw" his new "nebula".

Altogether, then, the idea of a switched sign may be possible, but I do not think it likely to be what really happened here.

So, IC 1572 is still lost.

― IC Notes by Harold Corwin

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