RESULTS OF AN IDENTITY SURVEY OF IC GALAXIES.
(Completes all IC identified galaxies).
(Updated to May 6th 2005.).
EXPLANATION OF SURVEY RESULTS.
This is an updated version completed by me on May 6th 2005. and primarily it 
results from making a completely new comparison of my previous survey results with 
those recently published on the web site by Dr. Harold Corwin (November 19th 2004)  
and Wolfgang Steinicke (March 31st 2005) and following changes and these changes are 
as given below.
(A).  Identity problems for which I have arrived at a different conclusion than I 
previously stated.   
(B).  Identities that I had previously omitted in my survey due to my belief that 
they represented astronomical objects that I had been previously thought to be 
other than galaxies and therefore beyond the scope of my survey or that I had just 
overlooked and which have now been added.  They are for IC 468, IC 1111, IC 2115 
and IC 2729. 
This version again presents NOMINAL and/or CORRECTED NOMINAL coordinates for both 
Epoch 1950 and 2000.
All the coordinates I have given following the discoverers name are derived from 
the data provided by the different discoverers in their published lists or 
catalogues and these I have divided into two separate types of nominal positions.
TYPE 1. NOMINAL COORDINATES.  These are completely reliant upon the stated 
coordinates of the observer whose published lists contain no statistical 
information as to any reference stars.  This makes up by far the largest group of 
the IC observers.
For such, the investigator can only take the given positional data and enter it by 
Observational Epoch into NED's COORDINATE AND EXTINCTION CALCULATOR and obtain 
precessed coordinates for  the desired years, in my case 1950 and 2000.  With TYPE 
1. this is the best one can hope for and thus TYPE 1 Nominal Position results are    
entirely dependent upon the accuracy of the published historical data.
TYPE 2. CORRECTED NOMINAL COORDINATES.  These are historical positions for which 
the following discoverers, (Bigourdan, Javelle, Spitaler, Parrish, Muller, 
Leavenworth and Stone) provided the reference star's identity and coordinates for 
their selected Epochs and the offsets they measured in order to arrive at the 
coordinates for their discovered objects.
Much greater accuracy can be determined from this data as the reference star can 
be equated with its modern identity from a number of sources, such as the GSC 2.2, 
Tycho-2 or Astrographic Catalogue 2000.2 (AC), which is the catalogue I used the 
most due to it giving precessed coordinates based upon Observational Epochs close 
to the years the Type 2 observers were carrying out their observations.
The method I employed was to obtain from NED the year 2000 coordinates for the 
reference star by precessing from the discoverer's data and given Epoch, then 
putting the results into the AC with a search radius of 1 arcmin which resulted in 
giving the modern identity of the star and its year 2000 position.  Next I put 
these coordinates into NED's Coordinates and Extinction Calculator and precessed 
back to the discovery year and then applied the measured offsets to the discovery 
year data after which I again used NED to precess to the years 1950 and 2000.
It must be remembered that those observers employing reference stars obtained 
their coordinates for these stars from the Bonner Durchmusterung or other 
available star catalogues which although they may be considered as being the 
earliest accurate star catalogues still they do have, on occasion, significant 
positional errors for some of their entries, therefore the published historical 
positions by the discoverers will reflect any such errors, however, by employing 
the Type 2. Corrected Nominal Positions method much greater accuracy is obtained 
once the historical reference star has been correctly equated with its modern 
equivalent and then the above mentioned precession procedures are employed for 
each object involved.
Occasionally, those observers using reference stars created additional errors such 
as incorrectly identifying their reference star or reversing their offset signs in 
one or both directions.  Such possible errors should be checked out by the 
investigator when the Type 2 procedure fails to land on or very near a nonstellar 
image and in those cases involving incorrectly identified reference stars other 
similar stars should be looked for and the offsets applied to them in order to 
determine whether there are acceptable nebular images at the proper offsets.
I would also like to say that the Type 2. method was suggested to me by Dr. Harold 
Corwin as a way to obtain accurate Corrected Nominal Positions and I am most 
grateful for his kindness in explaining to me, step by step, how to obtain the 
results I desired.
It should be clearly understood that Type 2 Corrected Nominal positions apply only 
to those IC galaxies discovered by the above mentioned 7 discoverers. 
For this version I again re-examined every IC identity in my survey and found it 
necessary to revise some of my earlier conclusions.
A few identities that I had listed as "Not found" were changed to present possible 
viable candidates and although I find that Corwin, Steinicke and I still have 
differences regarding some identities the number of differences is growing ever 
smaller with each of the revised versions we present.
Malcolm J. Thomson F.R.A.S.  142 Ely Street, Oceanside, 
California 92054.  May 6th 2005. 2004.