Repost of NGC 7234 which Space Banter Lost

NGC 7234 was discovered by William Herschel on October 16, 1787 but when his sister reduced his coordinates she made an error. She referenced a vacant piece of sky just below my image. Thus many catalogs list NGC 7234 as non existent. Not finding anything at his dad's position as recorded by his aunt John Herschel found and recorded the cluster at its correct position on September 24, 1829 which he included in his General-Catalog. Unfortunately when John prepared his General-Catalog in 1864 he missed the correction to the position of NGC 7234 by Arthur von Auwers published 2 years earlier. Both were included in his General-Catalog. When Dreyer prepared the NGC 25 years later he listed "both" clusters not realizing there was nothing at the position for NGC 7234 or that von Auwers had discovered it was John Herschel's cluster. So today some sources like WEBDA omit NGC 7234.

By whichever name you desire, the cluster is about 9,200 light-years distant in southern Cepheus less than a degree south of Zeta Cephei. WEBDA lists its age at 11.8 million years which makes it quite young. At that age I expected its stars to be blue rather than white but WEBDA lists it as being reddened by nearly a magnitude. I'd not think that sufficient to turn very blue stars white but apparently it is. The Sky shows the bright orange star as being only 65 light-years distant so it isn't a cluster member. The cluster's Trumpler classification is II3m. Even though discovered by William Hershel and a rather easy cluster visually it didn't make either of the Herschel 400 observing programs, possibly due to the position error for William's discovery of it.

For my previous post of NGC 7245 I only had a single color frame of each color to use to prepare the image. I got several emails wondering how much this altered the image. Since this was taken a much better night in which all luminance frames were usable I prepared two versions, one with luminance data, the other using only the single color frame of each color I took. I didn't take 2 color frames since no satellites needed removal.

14" LX100R @ f/10, L=4x10' (one version) RGB=1x10' (both versions), STL-11000XM, Paramount ME

Rick

One of the three didn't make it trying again.

Great image of a beautiful galaxy Rick. I should put it on my list in spite
of it's southern declination.

Stefan


"WA0CKY" schrieb im Newsbeitrag ...


NGC 1421 is a strange near edge on galaxy in northern Eridanus about 90
million light-years distant by redshift and 83 by Tully-Fisher
measurement. It has high surface brightness distorted arms in an
otherwise low surface brightness disk. It's been on my to-do list for
years but being so far south (-13.5 degrees) seeing never was up to the
task until this October night. NED classifies it as SAB(rs)bc: with
HII. It's redshift moves the H alpha emission well out of my passband
and I was unable to pick it up this low with RGB filters. The NGC
Project classifies it as Sb+ I: while Seligman agrees with NED. But he
mentions that de Vaucouleurs uses it as an example of a SB(s)c galaxy.
No two papers I looked at seemed to agree on its classification. One
admitted "Classification is difficult." Yet another said it was simply
Sc (no bar).

I measure the distance from the core to the southern edge of the galaxy
at 131" while the north segment is only 95". This makes for a rather
lopsided galaxy. Though this is partly offset by the odd third arm that
curves outside the normal oval to the northwest. There seems to be some
debate on the nature of this odd blob. NED considers it part of the
galaxy but one note at NED has this comment: "Its dwarf companion S2
could easily be mistaken for a background galaxy, except for its two HSB
nuclear H II regions." It appears to be talking of this blob as it does
contain two High surface brightness regions and I find nothing else the
comment could be about. Still I think it part of the galaxy. By my
measurement NGC 1421 is almost 100,000 light-years in size.

The galaxy was discovered by William Herschel on February 1, 1785. It
is in the second Herschel 400 observation program run by the
Astronomical League.

While NED lists over 150 galaxies in the image none but NGC 1421 have
redshift data. With nothing worth annotating no annotated image was
prepared. For some unknown reason when I centered the galaxy I had a
bad ghost reflection. I had to move it off center to get rid of it.
Nothing bright is in the area so I'm puzzled by the source of the
reflection.

14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

Rick


--
WA0CKY