Friday, 21 October 2016

Thanks Karen!


Thanks for the great talk Karen! Shoalhaven Astronomers were treated to a feast of solar animations on 21st Oct 2016. The challenges in getting time-lapse of solar transients can be daunting: but Karen succeeded. We watched hard-to-see events unfold in amazement, as 'roos grazed the lawns outside. The low density solar chromosphere is dominated by magnetic fields: matter flows sedately - then abruptly plunges to the surface or 'pops' into space without warning. Incredible physics! A great night.

Sunday, 16 October 2016

NGC1532 'Woomera'

Most galaxies are ‘poker-faced’ – giving little away: featureless ovals with faint nuclei; but some offer a glimpse of a more dramatic existence –when galaxies collide.  One such is N1532 (Dunlop 600) in the constellation of Eridanus, the River.
On first impression this is a big edge-on spiral with, seemingly, two nuclei! Higher power shows a small bright elliptical ‘object’ almost in contact with the edge-on’s nucleus. Are these interacting galaxies? References suggest they are: although there is no extended disc to be seen around the small galaxy, NGC1531. The common name for this galaxy pair is ‘Woomera’, the long thin Aboriginal spear-thrower.
In fact, this object seems to still have the ‘spear’ attached! Repeat viewings showed a thin strand of galaxy ‘arm’- aimed at a nearby field star. The whole scene was much like a ‘Mimi’ art figure from Arnhem Land in Australia’s north (Fig). 

Saturday, 1 October 2016

Enigma: NGC55

This is a large member of the Sculptor Group of galaxies; but what are we seeing? Apparently, an edge-on view, but with the bright core to the W and only a fainter arm to the E? A Gendler image suggests the bright 'cigar' is the central core seen through an outer arm of blue stars. Several small 'knots' are likely OB clusters of activity. A possible stellar central nucleus is arrowed. Reference stars are noted in case we see a super nova! This galaxy is seen well in a 4in 'scope. Is NGC55 a barred spiral with only the E arm visible - the W one hidden from view?