Weltevreden Farm 13 kms west of Nieu-Bethesda , South Africa. Equipment is a Celestron C6, Intes MN61 & MK66, Santel 180 F/10, and Bosma Mak 200mm f/12.
Tom Polakis Tempe, AZ Visual observing, DSLR photography, lunar & planetary imaging http://www.pbase.com/polakis/
Quote:Within our own Galaxy, where, moreover, small instruments can be brought to bear, we observe a *very* much wider array of objects in close proximity which interact on vastly smaller time scales. Much more accessible, and relevant.
I see the extragalactic scene as more of an academic exercise, whereas the situation within our own galaxy is of immediate import and interest as regards the history of our solar system--and other readily observed, nearby objects.
C10NGT, Z8, 150 Rumak, XLT 150, C6, C5, SW5 Newt, 4.5 Ball, C102GT, C90, ST80, A70LF; 15x70, 25x100; Burgess BV; Paracorr II; T6 2.5, XO 2.58/5.1, Ethos-SX 3.7, Delos 4.5, TV Plossl 7.4-26, BCO 10, Hutech HC 12.5, Sterling 12.5-25, ES100 14, CZJ H 16/25, CZJ O 16, M5k UWA 24, T5 31, Ultrascopic 35, Titan-II 40; Bino Pairs M5k UWA 6.7, Baader Zoom 8-24, M5k SWA 24, TV Plossl 26, RKE 28.7; Zooms NZ 2-4, NZ 3-6, Leica ASPH 8.9-17.8, Baader 8-24; Baader Zoom Barlow, VIP Barlow
Quote:Niels,I wasn't trying to start a 'debate.' But I guess I did, in a way. Some years back I purchased Tully's galaxy atlas. After many, many hours of bending my mind over the various 2-D and 3-D charts, I still found it not so easy to retain a coherent picture. And I suppose it was just a lack of fascination which kept me from persevering. But I did try! At least I have a picture built up of our own Local Group of galaxies...
Quote:I must mention a neat, free, software package which should fill the bill for both our home galaxy and the larger universe of galaxies...Partiview, from the Hayden Planetarium. You can get either or both of a set of databases, for the Milky Way and for external galaxies. It's OpenGL-based, and so looks very nice. And it doesn't generate a Windows registry entry, meaning you can simply drop it anywhere in your machine.Incidentally, I supplied the OB association database, after noting this lack when I first tried the package in 2003. Which illustrates the fact that the user can fashion any database imagined...
Quote:I sense there are many discoveries, and joys, to be had at any level of our study. Like Glenn, I am most fascinated by the magnitude and minutia of our host galaxy. I could say the same were I to zero in on the Carina Nebular Region, the Local Group, the solar system, the Moon. No matter the distance, there something to learn, teach, and enjoy. And instrumentation or personal budget need not limit our horizons, either. I'm limited to 200mm on an alt-az. Yet recently I tracked down several PGCs in Abell 1367 in Norma. Three faint fuzzies, ephemeral yet there. There are the most visible in the Norma Cluster. Research in to that led me to the Great Attactor, the ten years of investigation that finally charted the Galactic Superplane, Shapley Supercluster, and immense filament on all which all these lie. Yet even that was not the end of the fun. I came across a recent paper by Beygu, Krekel et al in the Netherlands, which identifies a 3-galaxy group designated VGS-31 (Markarian 1477 & Arekelian 409) that has evolved from the influence of dark, not baryonic, matter. It formed in one of the galactic voids completely isolated from the type of filaments on which the bulk of galactic clusters lie. [see: ]http://arxiv.org/pdf/1303.0538v1.pdf] These three galaxies, the Begyu paper asserts, evidence properties unlike other galaxies. I felt a sense of what Tycho Brahe may have felt when he looked up from his armillaries nd sextants at the apertures in the roof of his half-subterranean observatory, and said to himself, 'Beyond these apertures are matters I shall never see, but know are there.'So where in all the above is our Milky Way? What's the connection? The Norma Cluster, Great Attractor, and a dozen other clusters from Antlia through Pavo pass through the Zone of Avoidance, our own Galaxy's disc of dust and gas. Our Galaxy's extinction zones mimic supergalactic filaments in their intricacy and gravitationally-driven properties. Starting with Shlegel et al in 1998, the darkness in our galaxy has been mapped till it's as lucid as light. I can see these very same obscuring filaments in a Norma eyepiece field as intricately woven as star lanes in a great globular. There is as much to learn, and again, in which to take joy, in the darkness as there is in the light. Those dark threads of dust in our very own spiral arm, are Tycho Brahe holes in the roof, beyond which great wonder lies.
Quote:Thanks, Neils. What a great Web site! I will look at anything from the moon through quasars, but there aren't many subjects that interest me more than large-scale structure of the universe. My eye-opening moment in this subject came about when I was observing the Local Group in 1990, and as part of my library work, discovered Tully's Nearby Galaxies Atlas. It contains unique 2-D representations of the 3-D structure, plotted in an atlas that's similar in size and format to Tirion's Sky Atlas 2000.0.When I'm looking at galaxies through the eyepiece, I am constantly trying to get my arms around their relative distances. While none of us can relate to these distances, we can comprehend them.Tom
Quote:Has anyone tried this program? Where is M13? It looks like a much simpler way to get a good overview - literally and figuratively - of the structure of our galaxy without an overabundance of intervening verbiage or math. I think a visually-based understanding is probably best for most humans. Mike