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Pictures of Pluto (APOD 3 Sep 2006)
Posted: Sun Sep 03, 2006 4:05 pm
by Carol Lauer
Why is it that we can see wonderful detailed pictures of galaxies and cannot see a detailed picture of Pluto which is so much closer???
Posted: Sun Sep 03, 2006 4:17 pm
by rigelan
It might be because of the apparent width of the objects. Galaxies, even far ones have an decent width (degrees or minutes or even seconds). I'm guessing that the appart width of pluto is just less.
This link shows how accurately the hubble telescope can see at different distances.
http://sm3a.gsfc.nasa.gov/messages/676.html
If at the distance of the moon (384,000 km), hubble can see at a resolution of 124 meters, then at a distance of pluto, (4,500,000,000km from the sun), it should be able to pick out points 1400 km wide. Pluto is 2300 km wide, so pluto is just 2 pixels wide.
Pluto
Posted: Sun Sep 03, 2006 4:50 pm
by karfmusic
I would like to know why we cannot get a clear picture of the
dwarf planet Pluto, when Hubble can obtain strikingly clear images
all the way into the Deep Field. Can anyone give me a viable answer ?
Posted: Sun Sep 03, 2006 7:52 pm
by craterchains
It is not powerful enough.
Norval
Posted: Sun Sep 03, 2006 8:33 pm
by cosmo_uk
As an example, Hubbles Advanced Camera for Surveys Wide Field Camera used for most of hubbles galaxy images has a resolution of 0.05 arcsec per pixel. Pluto has a size just under 0.1 arcseconds on the sky so it is only covered by 2 pixels. The pretty galaxies we see in hubble images subtend a larger angle on the sky and so can be seen more easily.
Posted: Mon Sep 04, 2006 6:33 am
by makc
Posted: Tue Sep 05, 2006 6:48 pm
by iamlucky13
Of course, Hubble can't focus on objects as close as the moon. It would be blurry. I think even pictures of Mars I've seen through the Hubble show the limitation in resolution is the depth of focus, not the perfection of the optics or the size of the CCD pixels.
Rigelan is pretty much on mark. In fact, I just read today that the full extent of the Andromeda galaxy is wider than the moon in the sky, but most of that is the dim outer arms that can't be seen with the naked eye...but they look fantastic in a long hubble exposure.
I'm excited to see the pictures returned by New Horizons in 8 or 9 years. They won't be as spectacular as Cassini's pictures of Saturn, but they'll be an incredible leap over what we currently have.
Posted: Mon Sep 18, 2006 12:45 pm
by orin stepanek
Some interesting news about Pluto.
http://www.space.com/pluto/
Orin
Posted: Mon Sep 18, 2006 1:12 pm
by ckam
"news"
Posted: Mon Sep 18, 2006 1:58 pm
by orin stepanek
ckam wrote:
"news"
Pehaps I should have said [data].
Orin
Posted: Mon Sep 18, 2006 2:05 pm
by ckam
iamlucky13 wrote:Of course, Hubble can't focus on objects as close as the moon. It would be blurry. I think even pictures of Mars I've seen through the Hubble show the limitation in resolution is the depth of focus, not the perfection of the optics or the size of the CCD pixels.
here are hubble pics of jupiter. doesn't look too sharp, but hey can you make better picture from earth?