G'day there Les,
I really enjoyed reading your visual observations of A3574. Your explorations of this cluster must have been very enjoyable!
In my opinion, the various galaxy clusters and galaxy groups in Centaurus that are found at this considerable distance , are still largely 'unknown territory' for most observers, despite the remarkable nature of these distant galaxy-rich structures.
In case you missed it, there is an interesting discussion of IC 4329 and
IC 4329A and Abell 3574, in the Science forum:
http://www.iceinspace.com.au/forum/s...d.php?t=110009
Note especially my morphological notes on IC 4329 at the end of the thread;
- complex and unusual structure....it is not quite type S0 and not quite an elliptical galaxy
- IC 4329 is remarkably blue, compared to the typical elliptical galaxy
- there is a diffuse outer envelope which is not a disk, and which is of highly uncertain 3-D shape
- this galaxy has shells or steps in its outer light, the sign of previous galaxy merger activity
As a really serious student of galaxy morphology, I would be very interested in hearing about accurate observations of the very-centre/nucleus/nuclear-regions, of IC 4329 and IC 4329A, especially with very good optics and very good seeing!
(Personally, I think it is feasible that dust lanes might be visually observable in good seeing, near the centres of some elliptical galaxies, due to the high surface brightness.)
Much of the structural detail that I noted about the 'envelope' of I4329 is not observable by visual observers, but I would like to see really accurate descriptions of the centralmost regions of galaxies by visual observers.
Over the years, in IIS fora, I have posted quite a lot about the structure of the nuclear regions of galaxies, in order to give visual observers a "toolkit" which enables them to understand the various sorts of structures that can be observed near to the very centres of galaxies.
cheers,
Robert
One more interesting point that I would like to extract from the other thread is that the great Alan Sandage, a man who "almost knew galaxies in the face-to-face sense", was able to make good distance estimates of clusters of galaxies, using simple and easily-observable parameters such as the angular diameters and surface brightnesses of the member galaxies.
He did this to great effect in his monumental "Virgo Cluster Catalog" (= the VCC) , when he used the 200 inch at Mount Palomar to photograph the entire Virgo Cluster of Galaxies.
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