Hubble pictures
Ed Huesers
Ilja Friedel
> http://www.dailymail.co.uk/pages/galleries/index.html?in_gallery_id=9139&in_page_id=1055
They are very nice, but I suspect also heavily photoshoped. The stars are
very artistic and the colors in all likelyhood not real and picked for
aesthetic reasons. Maybe Eugene knows more. An example (still impressive)
that I remember is http://www.msss.com/mars_images/moc/2003/05/22/
Ilja.
Bruce Jensen
The Hubble pix are generally enhanced, at the admission of NASA. That
does not, however, take anything away from the amazing and splendid
detail that is captured in the Hubble's photos, and other than color
and contrast tinkering, nothing is added or subtracted.
Bruce Jensen
Eugene Miya
>> http://www.dailymail.co.uk/pages/galleries/index.html?in_gallery_id=9139&in_page_id=1055
M104.
You can see this one sometimes in the old Outer Limits credit sequence at
the end.
In article <eo1rr6$fvl$1...@naig.caltech.edu>,
Ilja Friedel <il...@sue.caltech.edu> wrote:
>They are very nice, but I suspect also heavily photoshoped.
Huh?
>The stars are
>very artistic and the colors in all likelyhood not real and picked for
>aesthetic reasons.
Modern astronomy by in large doesn't depend the human eye looking at a
scene. This is spectroscopy is for. The human eye has response problems.
You could be seeing things which are merely overexposure. Stretching
the dynamic range of an image for human is only occasionally done to
enhance contrast, it's not considered a manipulation of the original data.
Ask the source.
>Maybe Eugene knows more. An example (still impressive)
>that I remember is http://www.msss.com/mars_images/moc/2003/05/22/
Oh Mike Malin's firm. I once had an office 3 floors above him at JPL.
He was in the Antarctic at the same time as one of my trips, and we have
friends in common (Mars Underground).
--
Ilja Friedel
> Ed Huesers <e...@grandshelters.com> wrote:
>>> http://www.dailymail.co.uk/pages/galleries/index.html?in_gallery_id=9139&in_page_id=1055
> M104.
> You can see this one sometimes in the old Outer Limits credit sequence at
> the end.
> In article <eo1rr6$fvl$1...@naig.caltech.edu>,
> Ilja Friedel <il...@sue.caltech.edu> wrote:
>>They are very nice, but I suspect also heavily photoshoped.
> Huh?
What makes the stars have crosses go through them? If I want to achieve
this with a camera I have to buy a "star effect filter" to degrade the
image. I doubt they mounted one on Hubble, so where do they come from?
>>The stars are
>>very artistic and the colors in all likelyhood not real and picked for
>>aesthetic reasons.
> Modern astronomy by in large doesn't depend the human eye looking at a
> scene. This is spectroscopy is for.
I know.
> Stretching the dynamic range of an image for human is only occasionally
> done to enhance contrast, it's not considered a manipulation of the
> original data.
Alberto Korda had a fairly boring picture of a Cuban revolutionary. Once
he cropped it and enhanced the contrast it became one of the most famous
images of the last century.
> Ask the source.
I wish I could. A science picture without context, is it art?
Ilja.
Bruce Jensen
> Eugene Miya <eug...@cse.ucsc.edu> wrote:
> > Ed Huesers <e...@grandshelters.com> wrote:
> >>> http://www.dailymail.co.uk/pages/galleries/index.html?in_gallery_id=9139&in_page_id=1055
>
> > M104.
> > You can see this one sometimes in the old Outer Limits credit sequence at
> > the end.
>
> > In article <eo1rr6$fvl$1...@naig.caltech.edu>,
> > Ilja Friedel <il...@sue.caltech.edu> wrote:
> >>They are very nice, but I suspect also heavily photoshoped.
>
> > Huh?
>
> What makes the stars have crosses go through them? If I want to achieve
> this with a camera I have to buy a "star effect filter" to degrade the
> image. I doubt they mounted one on Hubble, so where do they come from?
The crosses are diffraction spikes from the secondary mirror supports.
On bright point sources, they are ubiquitous on scopes of this design.
Any photo taken through a Newtonian reflector scope with similar
supports, for example, will show these, unless they are digitally
removed.
Apparently, in digital photos, sometimes the individual pixels cannot
absorb so many concentrated photons, and the photons then tend to "fall
out" along horizontla and vertical columns. I don't knwo much about
this, but I do not think that's the case here.
Bruce Jensen
Eugene Miya
Ilja Friedel <il...@blinky.caltech.edu> wrote:
>>>> Hubble
>> M104.
>>>They are very nice, but I suspect also heavily photoshoped.
>
>this with a camera I have to buy a "star effect filter" to degrade the
>image. I doubt they mounted one on Hubble, so where do they come from?
Oh, probably the CCD array's saturation (overexposure/sampling) along the
dimensions of the array.
Ask the guys at the STSCI.
>>>The stars are
>>>very artistic and the colors in all likelyhood not real and picked for
>>>aesthetic reasons.
>> Modern astronomy by in large doesn't depend the human eye looking at a
>> scene. This is spectroscopy is for.
>
>I know.
OK.
>> Stretching the dynamic range of an image for human is only occasionally
>> done to enhance contrast, it's not considered a manipulation of the
>> original data.
>
>Alberto Korda had a fairly boring picture of a Cuban revolutionary. Once
>he cropped it and enhanced the contrast it became one of the most famous
>images of the last century.
You mean Che Gueverea? sp.
I think leftists would not think him boring.
There are a couple of books: Making People Disappear and
Spotting Photo Fakery (amusing where I purchased my copy of that).
>> Ask the source.
>
>I wish I could. A science picture without context, is it art?
Well, it's not Impressionism.
Painting? No.
Sculpture? No.
...
It's certainly part of the art of phorography (being an image).
The STSCI has a fairly responsive web site/email contact because they
are required to.
--
Eugene Miya
Bruce Jensen <bpnj...@yahoo.com> wrote:
>> What makes the stars have crosses go through them? If I want to achieve
>> this with a camera I have to buy a "star effect filter" to degrade the
>> image. I doubt they mounted one on Hubble, so where do they come from?
>
>The crosses are diffraction spikes from the secondary mirror supports.
Oh you mean the spider holding the secondary?
No. It's blurred out of focus.
>On bright point sources, they are ubiquitous on scopes of this design.
>Any photo taken through a Newtonian reflector scope with similar
>supports, for example, will show these, unless they are digitally
>removed.
>
>Apparently, in digital photos, sometimes the individual pixels cannot
>absorb so many concentrated photons, and the photons then tend to "fall
>out" along horizontla and vertical columns. I don't know much about
>this, but I do not think that's the case here.
The photons are brought to a focus and their geometric projection is
just are lost as part of scattering.
To take a photo doing that has to be done with a focus
on the legs of the spider.
--
Eugene Miya
>>Well, it's not Impressionism.
>>Painting? No.
>>Sculpture? No.
>>...
In article <45a79eaa...@news.midmaine.com>,
Lobster Grrrl <lobste...@gmail.nospam.com> wrote:
>Art doesn't necessarily need to be based on something tangible. The
>conceptual art movement of the 60's and 70's gave us some fine
>examples of that.
Yeah hence Impressionism, abstraction, found objects, performance art.
But a lot of that is junk. Music and writing are considered arts as well.
--
Bruce Jensen
> In article <1168468367.0...@77g2000hsv.googlegroups.com>,
> Bruce Jensen <bpnj...@yahoo.com> wrote:
> >> What makes the stars have crosses go through them? If I want to achieve
> >> this with a camera I have to buy a "star effect filter" to degrade the
> >> image. I doubt they mounted one on Hubble, so where do they come from?
> >
> >The crosses are diffraction spikes from the secondary mirror supports.
>
> Oh you mean the spider holding the secondary?
> No. It's blurred out of focus.
I've never seen a view or a picture through a Newt that *doesn't* have
these. My own newts, including an 8" and an 18", both display this
effect. My refractors do not. The main diff in the light path is the
4-pointed "spider," and when focusing in and out, you can see the
points come into position as artifacts of the diffraction around the
spider "legs." The spider may be out of focus, but the photons
diffracting around the legs make nice sharp points on the stars.
Bruce Jensen
Ilja Friedel
Now I understand. I did not think of those. And makes a lot of sense, as
they only appear on brighter stars. Well, one could have hoped that in
zero gravity they could have done without the spiders (or very thin).
Thanks!
Ilja.
Alfred Falk
news:eo8ees$enh$1...@naig.caltech.edu:
It still has to be rigid and support a substantial mass through
movements even if gravity is not a problem.
--
----------------------------------------------------------------
A L B E R T A Alfred Falk fa...@arc.ab.ca
R E S E A R C H Information Systems Dept (780)450-5185
C O U N C I L 250 Karl Clark Road
Edmonton, Alberta, Canada
http://www.arc.ab.ca/ T6N 1E4
http://outside.arc.ab.ca/staff/falk/
Floyd L. Davidson
For those with less experience with telescopes and more with
traditional photography, consider the typical "filter" that can
be purchased to produce the star effects. It has a cross
pattern of lines, and is mounted just in front of the lense too
(i.e., out of focus). Same effect.
Another cause of the same effect in traditional camera
photography is diffraction at the aperture in the lens. A
typical lens might have a wide open aperture of something like
f/1.4 to f/4, and when "stopped down" will be f/22 or even f/32.
At the smaller apertures the diffraction is greatest, and the
blades of the lens form a pattern that shows up in two ways in
the resulting image.
Out of focus point sources of light will have the shape of that
pattern. In focus point sources will have the same star pattern
as discussed above, with one line shooting out for each "corner"
in the pattern. (For that reason, an even number of blades
produces half as many rays of light in the star pattern, because
they match in pairs. The ray will be twice as bright though.
With an odd number of blades their will be more points in the
star pattern, which is often considered a better looking result,
and therefore most lenses have an odd number of blades.)
--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) fl...@apaflo.com