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Old 01-04-2019, 08:37 PM
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Weltevreden SA (Dana)
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Join Date: Apr 2012
Location: Nieu Bethesda, Karoo, South Africa
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Nightfall DSO Journal in South Africa has posted two new publications

Hi to all our friends over there in Oz . . .



The Astro.Soc. of Southern Africa (ASSA) is please to announce our latest astronomy journals in the Nightfall DSO series. These are available for free download.

Nightfall April 2019 V.3 #2


The highlights of this issue are:

Martin Heiganís Vela Supernova Remnant (p.7) describes what happens in the million years after a supernova blast wave detonates into the complex environment a galaxyís disc. The article opens with a stunning Hubble HOO Palette image acquired by South Africaís Martin Heigan.

You CAN hear a scream in space (p.48) dissects the effects of gas pressure density waves (sound) in the extremely low densities and high temperatures of interstellar space. Middle C in space is roughly 40 octaves below middle B on a piano. First, invent a hearing aid that can detect one wave pulse per month. Then be patient.

The exotic world of bino-builds starting on p.61 illustrates the rich inventiveness of amateur astronomers when it comes to improving already good ideas ó in this case the binocular.

And for fans of those beautifully painstaking early astronomy maps and charts, Heveliusís 1687 Selenographia was the first meaningful map of the moonís surface. See p. 85. The lunar story continues on (p.96) to a sample of ten pages from his atlas of the constellations Firmamantum Sobiescanum. Many consider these to be the most artistically beautiful star maps ever made.

On the Trail of the Chameleon Tail


This article begins with a keynote image by your very own Greg Bradley, who acquired and processed the lead image specifically at our request after we had seen some of Greg's earlier work. Greg has done a real service to science with this image Well done, Greg!



So to the story: What would you do if you saw a 40-degree long streak in the sky as large as those glorious comets recorded in history? You would tell everybody, right?



But what if no one can see it because it is too faint? In fact, what if it is visible only in far-infrared, microwave, micron, and 21 cm radio bands?
So your problem becomes how to describe the invisible visible ó and then figure out what it is.



On the Trail of the Chameleonís Tail tracks down a feature that is startlingly obvious in the spectral bands generated by dust, but is so tenuous in the Milky Way disc that it lies below the 25 MPSAS faintness limit of the human eye. It has been photographed only a few times by amateur astrophotographers, but only by stacking so many images together that the rest of the field looks horribly over-processed.



After dissecting 35 pages of clues, the Chameleonís Tail is hypothesised to be the last surviving traces of an ancient supernova remnant as old as 2 million years.


This isnít really a discovery paper because the object was already known. Rather, but it is a rediscovery paper because itís the first attempt to define what it is.



Also enjoy the other 12 publications produced in the last year and a half by the Astronomical Society of Southern Africa on ISSUU.
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