Galaxy Catalog ID and Magnitude Sought

[William R. Mattil]

All,

In processing some images taken of NGC891 (Luminance Only) It appears
that there is a very small background Galaxy visible just above the
upper arm. Does anyone know of a way to determine what that Galaxy
actually is and its magnitude ?

Here is my Image:

http://www.celestial-images.com/Images/NGC891-3x300s-LRGB-1xBin-S.html

And from using Aladin I can easily confirm that it is a galaxy. But ID
become more of a challenge.

The best I can do is:

02:22:41.9 +42:22:42.2 20AG G140.39-17.38

Anyone ?

Regards

Bill

[Pierre Vandevennne]

"William R. Mattil" <wrma...@ix.netcom.com> wrote in news:97LFk.1567
$Ei5....@flpi143.ffdc.sbc.com:

No idea about the ID -

the image is very dark btw - is it 3x300s LRGB as indicated in the web
page's title (and in that case where is the RGB? ;-0) or is it shot in H-
Alpha as the astrodon mention in the text seems to indicate?

http://www.celestial-images.com/Images/NGC891-3x300s-LRGB-1xBin-S.html

I've found that, even in heavily polluted areas, h-alpha hurts rather than
improves most galaxies. You probably should go for longer exposures too.

[canopus56]

On Oct 4, 8:33 am, "William R. Mattil" <wrmat...@ix.netcom.com> wrote:
> All,
> In processing some images taken of NGC891 (Luminance Only) It appears
> that there is a very small background Galaxy visible just above the
> upper arm. Does anyone know of a way to determine what that Galaxy

> actually is and its magnitude ? <snip>

From Simbad Aladin plotter it looks like the galaxy is ZOAG
G140.39-17.38. The Aladin plotter renders the designated location
slightly offset from the galaxy.

http://simbad.u-strasbg.fr/simbad/sim-id?Ident=ZOAG%20G140.39-17.38&NbIdent=1

I don't see a magnitude value for the galaxy on the Simbad identifier
page.

Clicking the "Bibliography" link at the Simbad identifier page will
give you a list of articles and Simbad online databases from which the
original object designation was made -

http://vizier.u-strasbg.fr/cgi-bin/Dic-Simbad?ZOAG

I was not able to locate the specific entry ZOAG G140.39-17.38 in the
most recent catalogue entry J/A+AS/137/293 -

http://webviz.u-strasbg.fr/viz-bin/VizieR?-source=J/A+AS/137/293

- and the original source catalogue also does not include a magnitude
entry.

Since you have a number of catalogue bright stars in your photo, you
might want to try to use imaging tools like API4WIN to estimate a
magnitude.

- Canopus56