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View Full Version : Why can't we just focus Hubbel on Mars?


Homer
05-11-2000, 12:40 AM
If the Hubbel telescope can see so damn far away, why can't we focus Hubbel on Mars and get some damn good closeups?

Okay, now tell me why I'm an idiot.

--Tim

Narile
05-11-2000, 12:49 AM
I am not sure, but I am pretty sure that Hubble's focal range is not optimized for such close images. Also, Mars might have to great an albedo for Hubble, but I am not sure. Hubbles resolution might also not be adaquate for such a fast moving object as Mars.

Fyodor
05-11-2000, 12:52 AM
There is probably a waiting list years long for Hubble projects and every precious minute is booked and reserved by serious scholars who have to apply, in great detail, to be approved to use Hubble time. You could go through channels and try and book some Hubble time to try and identify pyramids on Mars but it would be a risky career move for any member of the Hubble Board of Directors to schedule you in. Closeups of weathered rocks and red dirt may not be time well spent. I don't think you are an idiot but a bunch of academic snob astronomers might suggest it.

zuma
05-11-2000, 01:07 AM
It appears Hubble has already taken several pictures of Mars, as well as most of the other planets in the solar system.

http://oposite.stsci.edu/pubinfo/SolarSystemT.html#Mars

The planetary pictures were taken with the "wide field" camera, so I am assuming they have different cameras/lenses for nearby vs. distant objects. I dunno.

Icerigger
05-11-2000, 04:41 AM
When comet shoemaker-levy 9 crashed into Jupiter the HST did take many good photos of the impact. The comet pictures were in newspapers throughout the world.

pluto
05-11-2000, 04:49 AM
Hubble's strengths are its ability to see faint objects (that's why it can see so far) and its high resolution -- the ability to distinguish two things very close together.

Mars certainly isn't faint and we have sent a lot of orbiters to Mars that have returned images of almost all of the planet at much higher resolution than Hubble can muster. It's not that the Mars probes had better imaging than Hubble, it's just that they were so very much closer that they could see so much better.

So the short answer to your question is that we don't use Hubble to take pictures of Mars because there is no reason to. We already have much better pictures.

scr4
05-11-2000, 04:56 AM
As the link posted by zuma shows, they have taken images of various planets. Planets and even the moon are far enough that no re-focusing of the telescope is necessary. Planets are also slow enough that tracking isn't a big problem. The images were taken with the Wide Field Planetary Camera 2, becaues that's the primary imaging camera of the Hubble. Other instruments are for infrared observation, spectroscopy, or more optimized for faint objects.

One reason you may not have seen those Mars images by Hubble is that they don't provide much new information. We have been sending probes there since the 60s (or is it 70s?) which sent us far better data. The Hubble images only tell us what has changed since our last probe - useful for studying the climate, I'd think, but not much else.

Guy Propski
05-11-2000, 08:02 AM
You could, but there's still a limit to the amount of information that can be gathered from just photos. For one thing, Mars does have an atmosphere, which can cause distortions to the image. For another, well, let me ask the question this way--which would tell you more about London, taking a picture of London or going to London?

We were able to take lots of photos of the moon, but we never learned more than what we did from the couple of hours the Apollo mission spent on the surface.

Sorry if I took this thread on a tangent.

CurtC
05-11-2000, 08:43 AM
Narile wrote:
I am not sure, but I am pretty sure that Hubble's focal range is not optimized for such close images.The focus of anything farther out than a few miles is at "infinity" anyway. There's no difference in the focus setting whether you're looking at the moon, Mars, or a quasar 13 billion light-years away.