In message <13s6rc21iedgcf1 RemoveThis @corp.supernews.com>, Nicholas O. Lindan
<see RemoveThis @sig.com> writes
>There seems to be lot of 'illumination' in these pictures
>(i.e. - an awful lot of photoshopping).
There has to be some work done to generate an image that will work on
the conventional printed page starting from the huge dynamic range of
the original scientific data. The illumination comes from stars in the
nebulae.
>
>You wouldn't think the Triffid shown here
>http://img.dailymail.co.uk/img/galleries/hubble/NO10_350x301.jpg
The Triffid is a very large nebula. The image above is one very tiny
part of it that you can see in the wide field view below. The dark
molecular cloud is casting a shadow against the bright yellow blob just
to right of centre.
They are two images of the same object but at very different scales. The
detailed one is something like 10x enlargement of the central patch.
>
>Has much in common with these other Triffids -
>http://www.world-mysteries.com/mpl_photos/astronomy/trifid_nebula_nasa1.jpg
>http://www.cuyastro.org/images/cukras-triffid-full.jpg
>
>At least the sombrero retains a bit of resemblance to its 'before' image:
>Before:
>http://photos.crosscountryadventures.us/albums/astrophotography/astropag
>e/sombrero360425es.jpg
>After: http://img.dailymail.co.uk/img/galleries/hubble/NO1_350x175.jpg
If you insist on choosing a really poxy photo as your comparison then no
wonder you are convinced that they are all fabrications. A more
realistic amateur image with decent kit is online at:
http://www.space.com/imageoftheday/image_of_day_040331.html
Plenty of others if you look arounf on the S&T site or Astronomy Now.
>
>After a while I am not sure at all what these things really look like.
>http://www.noao.edu/outreach/aop/observers/v838monharris.jpg
>http://www.therealuniverse.com/V838MONOCEROTIS.jpg
>http://hubblesite.org/explore_astronomy/skywatch/db/72/images/large.jpg
>http://www.nasa.gov/images/content/199918main_rs_image_feature_784_946x710.jpg
>http://picasaweb.google.com/LyndaMilo/EmailArt/photo#5121571450265059634
You seem to have a problem with understanding that photographs of very
large objects using Hubble have to concentrate on interesting small
regions. There is some photoshopping going on - their workflow suggests
two marginally incompatible versions each adding their own thumbnail to
NASA images, but they are doing little more than making the image
suitable for the printed page.
Astronomical objects are pretty peculiar things especially the emission
nebulae lit up by UV from young stars. Their light is essentially at a
very few wavelengths (and some of them where old traditional colour film
was insensitive). It wasn't until the mid 1970's that we had any full
colour images of what the sky would look like with more sensitive human
eyes.
I don't especially like some of the hyper spectral false colour stuff
but they have to do something to visualise the data. It would be no use
to anybody printed in IR or UV inks.
Regards,
--
Martin Brown
--
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