SUPPLEMENT NUMBER 4:
Recently Bob Hill of Amarillo, Texas and his colleague Jim Fitch
carried out a 3 night series of visual observations of the IC 919
Field of galaxies, employing identical 20 inch Obsession telescopes
placed at excellent dark sky sites in Texas and New Mexico,. Their
purpose was to find out just how many galaxy images they could
successfully see within the field parameters determined by Barnard in
his observation made with the Lick Observatory's 36 inch refractor on
April 14th 1890.
I think that it can be fairly stated that the problems involving these
identities are the most complex faced by the identity investigator and
that the best we can hope to accomplish is to attempt to match up the
identities with what actually exists in the field by using what little
historical evidence is available. [See my IC GALAXY SURVEY.
"CORRECTIONS"], however, all such matchings will always be just
"suggested candidates" and as such, some identities at least will most
likely remain open to challenge from other equally legitimate
candidates.
It is my opinion that the fully correct matching of Barnard’s 18
galaxies can never be definitively established due to (a) Barnard’s
less than precise positions, which when plotted onto
a photograph of the field show for most identities large
inconsistencies with what actually exists, (b) insufficient
descriptive data in Barnard’s publication (A.N.2998) and (c) the
acceptable field contains more than 18 galaxies, thus allowing for
multiple matchings. Additionally, these most recent visual
observations appear to create possible problems with some of the
modern candidates.
Dr. Harold Corwin, Brian Skiff and Wolfgang Steinicke have
investigated these problems and presented their candidates, while the
most recent investigations carried out by Bob Hill and Jim Fitch, were
also able to record 18 definite nebular images within a field range of
1 tmin 53.9 tsec RA and 7 arcmin 0 arcsec dec. (Hill), very similar to
what Barnard gives (Barnard’s field parameters are 1 tmin 49.7 tsec RA
and 5 arcmin 33 arcsec dec.) which would strongly suggest that Barnard
should have been able to have also seen the same 18 galaxies with the
Lick 36 inch telescope, although there can be an argument made that 3
of those recorded by Barnard may have been a different 3 than seen by
both Bob and Jim.
Meanwhile, Corwin's field parameters are 2 tmin 0.8 tsec RA and 11
arcmin 5.1 arcsec dec, Skiff's 1 tmin 53 tsec RA and 8.1 arcmin dec,
and Steinicke's 1 tmin 59.9 tsec and 3 arcmin 30 arcsec dec.
The 3 candidates in question are Barnard's Numbers 1,2 and 3, equal to
IC 917, IC 918 and IC 919, as although Number 3 is the brightest
galaxy in the field and is selected by both Corwin and Skiff as being
IC 919 = ZWG271-059, (Steinicke selects the galaxy at 13hr 42m 56.5s
+55 36’ 12” 2000, as IC 919), its fainter companion located just off
its south preceding edge was clearly visible to Hill and Fitch on all
3 nights they conducted their observations and thus would have been
even more visible to Barnard, yet he makes absolutely no mention of
any companion to his Number 3. If Barnard is not including any of
those galaxies immediately preceding and adjacent to ZWG271-059 then
the conclusion would be that Barnard’s Nebulae are made up of 15 of
those galaxies seen by Hill and Fitch and 3 fainter galaxies within
the field parameters but not seen by either Hill or Fitch, and that
Barnard's "cB, R, bM" = IC 919 would most likely be Steinicke's
candidate for IC 919 (Hill and Fitch's #4).
None of the investigators who have examined this problem are in total
agreement as to the likely candidates for the 18 IC identities and
this is entirely understandable, as considerable jockeying is
necessary in order to arrive at any reasonable set of candidates, it
is as Brian Skiff states “it’s a bit of a wash: you pays yur money,
you takes your choice.”
These visual observations by Bob Hill and Jim Fitch are the only such
observations I am aware of since those made by Barnard over 100 years
ago and illustrate the important value the qualified visual observer
can contribute in helping to establish viable data used in the attempt
to sorting out disputed identities. They are to be commended for their
interest and work in examining such a challenging field.
The first 4 of 5 DSS photographs of the Barnard Field give the IC
identity candidates as determined by Barnard, Corwin, Skiff, and
Steininke and illustrate the differences arrived at by each of these
investigators, while the final photograph (#5) show the field galaxies
that were observed by Hill and Fitch.
Hill stated that he had difficulty assigning his #3 to Barnard’s #3
(IC919), as the companion galaxy (#2) off its south preceding edge was
evident on each of the 3 nights he observed the field and should have
been relatively easy for Barnard, also he pointed out that as for his
#9 it was extremely difficult and that all he would say was that there
was something at the position.
Jim Fitch added he may have also glimpsed the very faint galaxy close
north preceding their Object #1.
Thus we have the suggested candidates or observations of 6 differing
investigators and it would appear that a final correct solution may be
beyond reaching.
Malcolm J. Thomson.
June 13th 2005.
BARNARD'S 18 NEBULAE: POSITIONS FOR J2000 EPOCH.
CORWIN'S CANDIDATES: J2000 EPOCH.
SKIFF'S CANDIDATES: J2000 EPOCH. (For IC 917 he has ? and for IC
935*?).
STEINICKE'S CANDIDATES: J2000
HILL AND FITCH'S OBSERVED GALAXIES: J2000 EPOCH.
