ASTRO: NGC 7242

NGC 7242 is a very large galaxy that anchors the NGC 7242 group. It is
about 250 million light-years distant. I can trace the plumes off each
end of the galaxy out about 490 seconds of arc on the luminance FITS.
That would translate to almost 600,000 light-years for its diameter. If
true that's one huge galaxy. I suppose it is possible some of this is
IFN or something else. Measuring the obvious diameter I get 334 seconds
of arc. That is over 400 million light-years. No matter how you look
at it, it is one big honker of a galaxy to use the scientific term. NED
classes it as E+? and cD?. The NGC project says simply E. This would
indicate they are unsure how much of its elongation is due to its nature
and how much has been caused by tidal plumes created when it interacted
and likely ate many members of the group. That is, much of its shape
may be due to indigestion from over eating in the recent past.

IC 5195 is seen against the galaxy to the northeast. It's redshift puts
it a tad closer which is likely the case. While NGC 7242 is rather dust
free and thus somewhat transparent I doubt it is as transparent as it
would have to be to see this small galaxy through it. I found no
classification for this small, but rather bright, galaxy.

IC 5193 another spherical galaxy to the southeast that is considerably
larger than IC 5195 but it too shows no classification at NED.

NGC 7240 to the southwest shows some hint of a tilted disk though its
overall shape is nearly round. It is classed as S0-:.

To the upper right of NGC 7240 is IC 1441 classed as SBa? A tightly
wound barred spiral, they think. IC 5192 is to the southeast making a
nice triangle with the other two. NED has little to say about it
however. To its west is IC 5191 which has the NED class of S0-a. The MCG
catalog gives its coordinates as the same as IC 1441 in error. So if
you wonder why I need two days to do these, its things like this that
can really take up time figuring out who is right and who is wrong.

I've listed a few other galaxies in the annotated image, some with
redshift data, some without if they seemed likely to be members of the
group. Most of the rest are anonymous in NED but for a few small IR
galaxies in the 2MASS survey.

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

Rick
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