Overlaid DSS image of NGC 4663, 30' x 30' with north at top and west to the right
IC 811, MCG-02-33-002, PGC 42946, SDSS J124447.05-101152.3
|Size ||0.783' x 0.595' @ 175°|
|Right Ascension ||12h 44' 47.0" (2000)|
|Declination ||10° 11' 52" S|
|Description ||vF, S, *13-14 f|
IC 811 = NGC 4663. Bigourdan found the galaxy in 1888, too late for inclusion in the NGC, but it did make IC1. Its position there is different enough from Tempel's estimated one for N4663 that Dreyer included it without hesitation.
Turning to Bigourdan's big tables, though, we find entries for both numbers. That for IC 811 has just two measurements on 13 May 1888. The mean offsets are +19.19 seconds in RA, and -7 arcmin 01.2 arcsec from a star identified as "A.G. Wien-Ott. 4631" which has an accurate and precisely given position.
On 8 May eight years later, he has four measurements for NGC 4663. The mean values are +19.15 seconds in RA, and -7 arcmin 01.7 arcsec from the same star. Bigourdan has no notes about the two observations being for the same galaxy. I suspect the reason that he did not notice this is that the data are on successive pages of the table.
I also suspect that Bigourdan did not prepare all the data for publication himself, but had help from one or more of the several people hired as "computers" at the Paris Observatory. They would have churned through the numbers as quickly as possible. Had they noticed the identical measurements, I suspect that they would have mentioned them.
In any event, the NGC position is a bit off. Dreyer cobbled it up from
Tempel's discovery note, which (roughly translated by me) reads, "About 8
arcmin south following NGC 4658 is a small, very faint (William Herschel class III) nebula.
it itself precedes a star 13-14 mag; a measure by me with the ring micrometer came to nothing." (I presume that the galaxy was too faint for him to measure accurately, or too far from the comparison star.) The galaxy is actually 7.2 arcmin south-southeast of N4658. This puts the nominal position far enough off that Bigourdan, taking it literally, found nothing where he was expecting it. However, just a few arcmin away just happened to be this small, faint nebula ...
The identity was apparently first noticed by the Mt. Wilson observers, and was copied into RC1 and MCG from there.
16 objects found within 120'
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