No high res pics of pluto even with Hubble

[raghavbala]

Hi

Im a new member around here.. and nowhere close to even an amateur in astronomy..But have a simple query, which has been pondering in my mind..

Have searched the net quite a bit for good pictures of Pluto - which i assumed should be available in decent resolution.. But, all I got was this..

http://www.solarviews.com/cap/pluto/pluto3.htm

My question is this.. When the Hubble telescope is able to take pictures of objects, events so many light years away (recently came to know that hubble caught a moment 500 mn light years from BIG BANG!), why aren't we able to get Hubble to take a good detail picture of Pluto ?

Is there a technical limitation ? Would be glad to hear your answers..

Thanks

Raghav Bala
India

[Communist Hamster]

Pluto may be relatively close, but it is small. The objects (like nebulae) that Hubble usually takes pictures of are enourmous.

[orcot]

Telescopes can only see objects that shines light.
Pluto in pretty far from the sun and recieves verry little light.
Earth recieves about 1370 watt/m²
So Pluto only recieves something like 5 watt/m²
and it only reflects around 60%.

This combinend with the fact that it's the smallest planet in the solar system+ the fact that it's light has to travel a other 30AU (=distance sun earth),to reach us makes it a real bugger to photograph it.

in short it's to small and it doesn't reflect enof light

[Billy T]

Telescopes can only see objects that shines light.
Pluto in pretty far from the sun and recieves verry little light.
Earth recieves about 1370 watt/m²
So Pluto only recieves something like 5 watt/m²
and it only reflects around 60%.

This combinend with the fact that it's the smallest planet in the solar system+ the fact that it's light has to travel a other 30AU (=distance sun earth),to reach us makes it a real bugger to photograph it.

in short it's to small and it doesn't reflect enof lightAll true. But I doubt collecting light is the problem. (I am too lazy to prove this with a resolution calcualtion.) Two new moons of Pluto have just been discovered by the light they reflect and they are much smaller than Pluto's moon Charon. The big telescopes on Earth surely do not achieve their theoretical resolution looking thru the air and Hubel is much smaller. Resolution is directly related to the mirror diamter. I think the reason there are no detailed surface photo is more related to resolution limits than lack of light (You could collect light all night.)

Soon to be launched (Early January 06) is the mission to Pluto. (The spacecraft was made by the group I worked with at Applied Phyicis Lab of Johns Hopkins U and I know the project leader, Glenn Fountain, well but I have had no contact with him since I retired to Brazil, 12 years ago.)

[Janus58]

Two reasons have been given and both are factors.

1. The resolution of the Hubble is just not good enough to pick out features on Pluto.

2. The dimness of Pluto. Even if the resolution was good enough, the lack of light causes a problem. The Hubble can get around this when it comes to these images of distant galaxies, by increasing the exposure time (many of these objects are much dimmer than Pluto), sometimes with exposure times of weeks.

The reason this doesn't work for Pluto is that Pluto rotates once every 6.37 days. With the long exposure times needed to get the hi-res image, the planet's features will have moved significantly. It would be like taking a picture of a spinning top with a camera set to a slow shutter speed; you would get a blur.

[blobrana]

Hum,
the Hubble can take lots of short photos about 6 hours apart and stack them up to give a total exposure time of many hours...

Sounds like the resolution power of the telescope to me.

[Lucas]

Soon to be launched (Early December) is the mission to Pluto. (The spacecraft was made by the group I worked with at Applied Phyicis Lab of Johns Hopkins U and I know the project leader, Glenn Fountain, well but I have had no contact with him since I retired to Brazil, 12 years ago.)

Do you know Alan Stern, the Principal investigator of the project?. There's an interview with him this week in Planetary radio

Interview here (http://www.planetary.org/radio/show/00000105/)

[Billy T]

Do you know Alan Stern, the Principal investigator of the project?...No, but thanks. I listen to his talk and corrected my prior post (which was based on the APL/JHU news letter the lab is kind enough to still send me, even in Brazil.) to reflect the launch window now opens 11 January 06. Pluto was recently inside Neptune's orbit and now is back outside and every week of delay of launch adds a year to the trip to Pluto (roughly). I think this is because they intentionally wanted the "fly-by" to be slow - I.e. most of the KE provided by the rocket and planet swing bys will be gone when the Horizons spacecraft get out to Pluto. Delay also hurts as the very thin atmosphere will be condensing back on Pluto and harder to learn what it is. Lets hope for 11 Jan launch.

Someone should tell EmptyForceOfChi to keep her rain/cloud making pyramids etc away from the cape. ;)

[Janus58]

Hum,
the Hubble can take lots of short photos about 6 hours apart and stack them up to give a total exposure time of many hours...

Sounds like the resolution power of the telescope to me.

That would be about 6 days apart. While this method works (it is the one the Hubble uses to take long exposures of objects that are blocked for a part of its orbit), the idle time between exposures would be so much greater than the actual exposure time as to make it an extremely wasteful use of telescope time.

[blobrana]

Hum,
Tnx, for correction.

The main point of the post was to say that even if you did do that the images would still be blurry...

The theoretical best minimum angle of resolution is proportional to the wavelength of the light and inversely proportional to the aperture diameter of the telescope.

http://www.courses.psu.edu/astro/astro001_pjm25/telesc2.gif

http://www.airandspacemagazine.com/ASM/Mag/Index/1996/JJ/plpt.html

[may_wentee]

I don't think we're going to find some nice warm seas on Pluto or any alien resorts for wayward space travelers. Might be just a little to cold and probably hasn't got much of an atmosphere either, if any at all. Best bet is to look somewhere else for that remote get-away outer space vacation place you've always been looking for. How about Zeta 2 Reticulae for starters?

[orcot]

Perhaps if we ever built thisexoearthimager (http://www.space.com/scienceastronomy/astronomy/exoearthimager.html)
Telescope we could get a nicer photo.

[CANGAS]

In Hubble's earliest days, when it still had its "defective" lens, it made brilliantly sharp pictures of solar system planets, whereas star pictures were blobs. After the corrective lens was installed, it became able to sharply focus upon very distant stars but planets then became blobs.

[Billy T]

In Hubble's earliest days, when it still had its "defective" lens, it made brilliantly sharp pictures of solar system planets, whereas star pictures were blobs. After the corrective lens was installed, it became able to sharply focus upon very distant stars but planets then became blobs.Interesting, but Pluto is 30 or more AU away and that, I think, is from an optical focus pov the same as the stars.

For Mars, what you say may well be true. Are the best photos of Mars surface from pre-correction plate Hubble? Do you have a reference? What ever happend to Perkins-Elmer (almost sure it was them) for cheating on the optic tests to make the delivery schedule?

[Janus58]

In Hubble's earliest days, when it still had its "defective" lens, it made brilliantly sharp pictures of solar system planets, whereas star pictures were blobs. After the corrective lens was installed, it became able to sharply focus upon very distant stars but planets then became blobs.

Really?

Then why does this image of Mars, taken with the Wide Field/Planetary Camera 2, the intrument with the corrected optics and the replacement for the WFPC 1 look perfectly sharp?

http://photojournal.jpl.nasa.gov/tiff/PIA01589.tif

Can you point me to a sharper picture taken with the WFPC 1?

[CANGAS]

Since the Hubble was first placed in orbit, it has enjoyed a number of changes and ADDITIONS.

Really.

The link provided by Janus58 is a picture of MARS, made with a camera later added to the original Hubble camera, about ten years later.

The thread starter asked about pictures of PLUTO.

Really.

Anyone desiring to waste an hour or two may Google "Hubble Pluto pictures" and try to find pictures of PLUTO which are sharper than what I can only call blobs.

Really.

[CANGAS]

BillyT:

Answers to your questions, in order:

I don't know.
No.
I don't know.

[Billy T]

BillyT:Answers to your questions, in order:
I don't know.
No.
I don't know.
In view of your "no" to if you had a reference and Janus58's post, I think your first post was in error. I am very impressed with Janus58. He not only has never been wrong (to my knowledge) in these astronomical questions, but has taught me a lot. For example, thanks to him I now know the moon orbits the sun, not the Earth and further more the orbit of the moon around the sun is always concave towards the sun, just as the Earth's is. Best way to think of this I believe is to consider that the moon just "wiggles" a little, sort of like small amplitude sign wave of 28-day period, in it’s ~1AU nearly circular orbit about the sun but the amplitude of the wiggle is not enough to make it ever convex towards the sun.

BTW, Janus58 if you are reading - thanks again for educating me.

[Janus58]

Since the Hubble was first placed in orbit, it has enjoyed a number of changes and ADDITIONS.
I never said it hasn't.


The link provided by Janus58 is a picture of MARS, made with a camera later added to the original Hubble camera, about ten years later.

No, it was taken by the WideField/Planetary Camera 2, which was installed in 1993, three years after Hubble was launched. This was the first servicing mission.

http://hubble.nasa.gov/missions/sm1.php

Note that there were two sets of corrective optics installed. One was set in front of one set of instruments, and the other was included in the replacement camera. The WFPC-2 is the camera that provides us with all those pretty pictures.

You might have confused the WFPC-2 with the ACS (Advanced Camera for Surveys), which was installed in 2002.


The thread starter asked about pictures of PLUTO.


You said:

In Hubble's earliest days, when it still had its "defective" lens, it made brilliantly sharp pictures of solar system planets, whereas star pictures were blobs. After the corrective lens was installed, it became able to sharply focus upon very distant stars but planets then became blobs.


You said planets, plural. You did not restrict your assertion to Pluto alone.

You also seem to equate the Hubble's optical defect to the equivalent of being near-sighted (the ability to focus on nearby objects while further objects are out of focus) while the corrective optics caused it to be far-sighted. (able to focus on distant objects, but not nearby ones)

This is not the case. The Hubble mirror suffers from spherical aberration. This causes a the mirror to have a ill-defined focal point. The incoming light does not converge at a single point, but is spead out over a small area. This blurs the image, no matter at what distance the telescope is focused.
The closest human eye analogy is probably astigmatism.


Anyone desiring to waste an hour or two may Google "Hubble Pluto pictures" and try to find pictures of PLUTO which are sharper than what I can only call blobs.
Since it is you that are making the assertion, the onus is on you to do the required search and provide the evidence to back it up.

[Pete]

Images of Pluto from Hubble Faint Object Camera (FOC) before and after COSTAR (the corrective optics module) was added to the telescope:

1990 - Pluto and Charon from FOC before COSTAR, compared with best ground based image:
http://imgsrc.hubblesite.org/hu/db/1990/14/images/a/formats/web.jpg
Source: hubblesite.org (http://hubblesite.org/newscenter/newsdesk/archive/releases/1990/14/image/a)

1994 - Pluto from FOC with COSTAR
These were apparently the first views of Pluto which allowed resolution of features on Pluto's surface.
http://solarsystem.nasa.gov/multimedia/gallery/Pluto01-browse.jpg
Source: nasa.gov (http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=569)

1994 - Pluto and Charon from FOC with COSTAR:
http://solarsystem.nasa.gov/multimedia/gallery/PIA00827-browse.jpg
Source: nasa.gov (http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=2100)

Later photos from the new Advanced Camera for Surveys, which replaced the FOC in 2002, have revealed more detail of Pluto's surface (although still pitiful compared to what we'd get from a flyby), and two more moons.

[CANGAS]

I feel no onus, Janus. I have been wrong so many times that I have gotten used to it. Just wait for the first it ever happens to you.

Regardless of any correctness or incorrectness in any of my posts, I would expect to see any vociferously interested poster, as, I am sure, the original thread starter would, provide Hubble pictures of Pluto showing surface DETAIL.

If the posted pictures are believed by the posters to show DETAIL, I have some real nice ocean front property in Montana that I will be glad to sell them. :rolleyes:

[CANGAS]

Really, I have no choice but to admit how dumb I actually am, but I do not wish to claim any more dumbness than I really deserve.

Really.

Google " hubble speed of light ". One of the listings will be " speed of light ". Its domain name will be " [url]www.astrosurf.com/miroir_grav/einstein_e.htm". I have been unable to directly key into the domain because it appears to be a subscription site. Once in through Google, select "section 3 B".

I experienced some difficulty making an image load, and my solution was to right click the blank square, save image as, and launch the saved image.

Happy Googling.

Really. :cool:

[Janus58]

Really, I have no choice but to admit how dumb I actually am, but I do not wish to claim any more dumbness than I really deserve.

Really.

Google " hubble speed of light ". One of the listings will be " speed of light ". Its domain name will be " [url]www.astrosurf.com/miroir_grav/einstein_e.htm". I have been unable to directly key into the domain because it appears to be a subscription site. Once in through Google, select "section 3 B".

I experienced some difficulty making an image load, and my solution was to right click the blank square, save image as, and launch the saved image.



I wouldn't exactly call that website an unimpeachable source of information.

[CANGAS]

But, Janius, you do not have a reliable opinion. Everyone who knows you already is aware of that sad fact.

Cangas has used up his alloted amount of time and energy for argueing with an idiot about something that is virtually worthless.

Cangas has left the building.

Sayonara.

[Billy T]

But, Janius, you do not have a reliable opinion. Everyone who knows you already is aware of that sad fact..... not "Everyone"

I have found Janus58 to be well informed, accurate and able to help me correct my erroneous, but common view, that the moon goes around the Earth and that the Earth's gravity at the moon surface is dominate one, when it fact it is not (the sun's is much stronger) and in fact moon is in orbit about the sun, not the Earth, as a result.

PS I now remember that the hubel defect was "spherical aberation" as Janus said and he is fully correct that this optical error does not favor either short or long focal lengths as you erroneously stated in your post. I can only judge who has a "reliable opinion" by their posts here and Janus58's are error free, as far as I can tell.

[Janus58]

But, Janius, you do not have a reliable opinion. Everyone who knows you already is aware of that sad fact.

Cangas has used up his alloted amount of time and energy for argueing with an idiot about something that is virtually worthless.



My, that was a little uncalled for.

[Pete]

Regardless of any correctness or incorrectness in any of my posts, I would expect to see any vociferously interested poster, as, I am sure, the original thread starter would, provide Hubble pictures of Pluto showing surface DETAIL.
There are no Hubble images of Pluto showing surface detail. The best that exist show fuzzy shadings, as shown in my previous post. They were taken after the corrective optics were added. Before COSTAR was added, Hubble could not resolve any difference in surface shading at all.

[shekhar]

Dear Raghav, The HUBBLE Telescope is not for take the pics in side solar system.......Its working is for next to our solar system....there are so meny other telescopes to take the pics of planets......just visit following link for recente pics...
http://www.sonnensystem.pointcom.eu.com/pluto.htm
if u want to see more details..........email me....i will send you that software......to view all the plants and also the all sky.....astroshekhar@yahoo.co.in