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Cotton, Condon & Arbizzani:

Arcsecond Positions of UGC Galaxies

ctsy. W. Cotton, TeX->ASCII and reformatting by H.Andernach 7/99
We present accurate B1950 and J2000 positions for all confirmed galaxies in the Uppsala General Catalog (UGC). The positions were measured visually from Digitized Sky Survey images with rms uncertainties sigma >= [ (1\farcs2)^2 + (\theta/100)^2]^{1/2}$, where \theta is the major-axis diameter. We compared each galaxy measured with the original UGC description to ensure high reliability. The full position list is available in the electronic version only. POSITION MEASUREMENTS Galaxy positions were measured from 6' x 6' FITS-format DSS postage-stamp images obtained from the Space Telescope Science Institute's WWW server URL {http://stdatu.stsci.edu/cgi-bin/dss\_form}. We obtained their POSS~II images if available and POSS~I images otherwise. Some entries in the UGC are multiple systems containing two or more galaxies having individual angular diameters <1'. We measured these galaxies individually, and they are distinguished in our list by the suffixes a, b, c,... in order of increasing J2000 right ascension. A sample of the UGC galaxy position list is given in Table 1. The first column contains the UGC catalog number, to which we have added lower-case suffixes a, b, c,\dots in order of increasing J2000 right ascension to distinguish individual galaxies in groups. Our suffixes usually agree with the lower-case suffixes found in the UGC notes, but not always. The second column contains the hours, minutes, and seconds of right ascension precessed to equinox J2000 plus the rms uncertainty in in seconds. The third column lists the degrees, arcminutes, and arcseconds of J2000 declination plus the rms uncertainty in arcseconds. Columns 4 and 5 give the corresponding B1950 right ascension and declination. The full list appears in the electronic version only.
Table 1. Optical Positions of UGC Galaxies
(N=13391 entries for 12910 unique UGC numbers)
#UGC Aa   RADEC_B1950         RADEC_J2000     +-s   +-"
00001a  000003.96+162224.8 000237.85+163906.8  .10  1.5
00001b  000004.06+162155.4 000237.95+163837.4  .10  1.5
00002   235952.03+443832.5 000226.14+445514.3  .13  1.4