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Re: APOD: Eta Carinae and the Expanding Nebula... (2014 Dec
Posted: Wed Dec 03, 2014 6:39 pm
by DavidLeodis
geckzilla wrote:star struk wrote:Eta Carina picture shows lines arranged in a hexagon pattern from star. Are these the 'whiskers' refered to in picture description?
The six lines which change orientation in one of the three frames of the animation are artifacts. They include the usual x-shaped diffraction pattern created by the struts holding up Hubble's secondary mirror and then one line bisecting them which is a charge bleed caused by electrons overflowing in the detector itself due to the extreme brightness of the star.
EtaCarinae_Hubble_artifacts.jpg
BTW, here is the animation on a forever loop that won't stop after only 5 plays.
http://www.geckzilla.com/astro/CarinaEx ... orever.gif
Thanks geckzilla for that explanation
, as it confirms what I had thought that the whiskers would not be the spikes.
I do wonder though where the "streaming whiskers" are in the image, as the explanation in mentioning them would seem to imply that they are obvious features.
Re: APOD: Eta Carinae and the Expanding Nebula... (2014 Dec
Posted: Wed Dec 03, 2014 9:25 pm
by geckzilla
DavidLeodis wrote:I do wonder though where the "streaming whiskers" are in the image, as the explanation in mentioning them would seem to imply that they are obvious features.
I'll outline what I think are the whiskers based on the descriptions
this paper. Within, it is mentioned that it is easy to conflate the point spread function with the whiskers, so it seems that the structures which line up the best with the diffraction spikes are the most likely candidates. The linear structure of the whiskers is not as apparent in the gif animation as in other versions of the Homunculus which may be processed to enhance them.
- Whiskers outlined in blue.
Re: APOD: Eta Carinae and the Expanding Nebula... (2014 Dec
Posted: Thu Dec 04, 2014 12:10 am
by DavidLeodis
Thanks for the help and link geckzilla.
I was amused by the 'curly hair' in the "HTS and Gemini instruments have two different point-spread functions and then, after the processing deconvolution methods have been applied to the relative images, the two systems give us an imaging of the central whiskers with different features, long and straight in the HST imaging, as curly hair in the case of the Gemini imaging".
Re: APOD: Eta Carinae and the Expanding Nebula... (2014 Dec
Posted: Thu Dec 04, 2014 12:13 am
by Ann
Yes, thanks for the helpful illustrations, Geck.
One of the whiskers, the one on the left, appears to be associated with an elongated structure looking like a jet, ending at about 11 o'clock. There might be an elongated structure on the right as well, ending in a bright "cloud" of turbulence.
Ann
