http://www.skyandtelescope.com.au 61Another questionable object is NGC 4317, which is listed as
a faint star. On the STScI image of the field of NGC 4317,
I noted several faint galaxies. I was able to locate three
of them through the 52.5-cm scope: PGC 1929454, PGC
1924297 and PGC 40071. They are all within 15′ of the star.
IC 4470 near NGC 5712 (both galaxies) is an example of a
possible Herschel object that I observed, though it’s not on
the original list of 2,500. In fact, I found that IC 4470 was
actually easier to spot than NGC 5712.Final tally
Do I believe that I’ve spotted all of the visible Herschel
objects? Probably, but I’m not sure that any of us who went on
this quest can say that with complete certainty. One difficulty
arises from of the method of recording object positions by
astronomers in the 18th and early 19th centuries. Charles
Messier, Pierre Méchain, William Herschel and others didn’t
use coordinates consistently in their catalogues. They also
gave positions in relation to nearby stars or other deep sky
objects. Mistakes were made when later astronomers tried
tomatchthedescriptionsoftheobjectpositionstoright
ascension and declination — M91 and possibly M103 are
examples of Messier objects with mistaken identities.
HowmanyHerschelobjectsareobservable?I’vefound
thatthetotalsvaryfrom2,397to2,520.Howmanyhave
Ilogged?Icounted2,517.Subtractingtheduplicatesand
multiple listings for NGC 2264 (cluster and nebula) and
M20 (four sections of the Trifid Nebula), my total number
of actual galaxies, clusters, nebulae, stars, multiple stars and
asterismsis2,477.
Besides these 2,500+ objects, Wolfgang Steinicke has
identified55moreobjectsthatHerschelobservedbutdidn’t
includeinhisthreeseparatecataloguesthateventuallybecame
hiscompletelistingof2,500objects.IcheckedWolfgang’slist
andnotedthatIhadobserved27ofthem.Ihaven’tdecided
yetwhetherIwilltryfortheremaining28.Ineedarestfrom
searchingforwhatsomeofuscallfaint fuzzies.
Iestimatethatsomeonewithexperience,goodvision,a
darkskyobservingsiteandthedesireforthehuntcanfind
allofWilliamHerschel’sdeepskyobjectswithscopesof35
to40cm.Goodlucktoallwhotrythisquest.Youhavetobe
obsessed,crazy,orbothtoattemptthis.IfeelIwasboth.Tracking down designations
The Space Telescope Science Institute (STScI) Digitized Sky Survey website (https://is.gd/stsci_dss) locates objects by
their designations. This is useful for identifying sources’ true names. Just input the object designation in the search bar,
and the website will return results indicating whether or not the object is truly known by that name or if it goes by another
one (for example, if it has another NGC number other than the one entered). You can also retrieve an image of the field.Another useful website for this purpose is the SIMBAD database maintained by the University of Strasbourg:
simbad.u-strasbg.fr/simbad/SCOULD IT BE? NGC 4317 was listed as a faint star by Herschel. Tom
Reiland couldn’t find the star when he observed the field but did spot
three galaxies, all within 10′ of the given position (box). Could one of the
galaxies be the actual object Herschel observed? TOM REILAND has been observing the night sky for more
than 45 years. He worked at the Allegheny Observatory as
the Assistant Astronomer for 22 years and Senior Observer
10 of those years, and then founded and became director
of the Wagman Observatory. Along with Tom Hoffelder, Tom
is one of several independent originators of the Messier
Marathon in 1975. In July 1985 Tom discovered an open cluster
subsequently named Reiland 1, and in 2004 he was honored
with the naming of asteroid (10320) Reiland. He was also the
first to report the discovery of SN 2011dh in M51.HERSCHEL CATALOGUE RESOURCES: Jim Mullaney, Wolfgang
Steinicke and David Bishop all supplied the author with useful
information in his searches. Here are some links:
messier.seds.org/xtra/similar/herschel.html
http://www.klima-luft.de/steinicke/index_e.htmPGC 40071PGC 1924297PGC 1929454POSS-II / CALTECH / STSCI / PALOMAR OBSERVATORY