Quote:
Originally Posted by ngcles
Hi John,
IAU circular 9103 issued on 1 January 2010 includes some very accurate photometry performed at Perth Observatory by David Frew and others that puts the magnitude of the central star (Eta itself) plus the Homunculus surrounding it at 4.65 in mid-November. I estimated it visually on 13th December 2009 at between 4.35 and 4.45 (the lower being the more likely). It had been estimated visually in early October 2009 at about 4.1. There were several visual extimates around the 4.5-4.6 mark in October-Nov. It just doesn't seem that long ago it was about mag 6.5-7.0 -- guess I'm showing my age!
This increase and variability in visual brightness is not necessarily evidence that "she's about to blow" but more likely that Eta is finally starting to clear the Homunculus away and shine out of it -- rather than through it.
It would appear therefore that as the material is being cleared out, there is less infrared and more of the visual and shorter wavelengths getting out. Change is occurring very quickly (on astronomical time-scales) and it is always interesting to watch.
Best,
Les D
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Thanks for the detailed info Les, a mine of information as usual!
This is very interesting as when I was observing Eta Car the other night I thought to myself "You know.I reckon thats brighter than last year" Last time I saw it was probably around June I think, and I cannot remember being able to find it so easily, in fact I was a little frustrated on a couple of nights when it was hard to find. Now you look and there it is. Might just be my observing skills are getting better
or the seeing was not very good last year, and the last week down here has been magnificent!