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Chip
2001-Dec-17, 08:46 PM
According to CNN, the next space shuttle mission will be in February, when a crew on board Columbia is sent up to work on the Hubble Space Telescope.

Public information page on the Hubble website has a story but scrolling down I see the mission they're talking about was in 1999! (They need to update their website.) http://oposite.stsci.edu/sm3a/index.html

Goddard Hubble page has no mission information (but really great pictures!): http://hubble.gsfc.nasa.gov/

Anybody know what the mission will be? Maintenance or new equipment?

Chip

ToSeek
2001-Dec-17, 10:25 PM
On 2001-12-17 15:46, Chip wrote:
Anybody know what the mission will be? Maintenance or new equipment?

Chip


Some of each: (http://hubble.nasa.gov/servicing-missions/sm3b.html)

- Replacement of the Faint Object Camera (FOC) with the Advanced Camera for Surveys (ACS) (http://acs.pha.jhu.edu/), a totally butt-kicking instrument that's a 10x improvement over anything that's gone before.

- Replace the solar arrays

- Replace power control unit

- Add new cooling system to the NICMOS

- Reboost HST to a higher orbit

The Bad Astronomer
2001-Dec-17, 10:36 PM
The GSFC Hubble page does indeed have what you want. Try here (http://hubble.nasa.gov/servicing-missions/sm3b.html).

The folks who run that page were all coworkers of mine until I abandoned DC for the left coast. Well, they weren't on the same project; I was on STIS and they were developing the Wide Field Camera 3 (WF3). But it was funny; we had the 'hubble' domain name for GSFC for one of the computers in my group, and the woman in the WF3 group wanted it, so we had to go through some paperwork to let her have it. I always smile when I see that URL.

Anyway, the solar panels are markedly smaller than the ones on HST now, so it'll look weird afterwards. I saw those panels shortly before I left GSFC. Some workers were hoisting them in their box, getting them ready to ship to Kennedy. That was very cool. The NICMOS cooler was there too, as was the body for WF3 (made from the leftover chassis from WFPC 1) and a few other odds and ends. Sometimes I miss being near all that excitement.

Chip
2001-Dec-17, 11:02 PM
Thank you BA & ToSeek! Great info.

Sounds like they're going to "soup up" HST quite a bit, as old hot-rodders say.

The ACS webpage states: "The ACS will increase the discovery efficiency of the HST by a factor of ten. It will consist of three electronic cameras and a complement of filters and dispersers that detect light from the ultraviolet to the near infrared (1200 - 10,000 angstroms)."

Wow! Will that mean they'll be able to resolve those tiny, extremely remote - hard to see red smudges (sometimes obtained with Hubble by using gravitational lensing,) into recognizable shapes? Some people call them: "early proto-galaxies," "proto-galactic sub-fragments," and even "train wrecks."

(My head spins just trying to think about how far away Andromeda is!)

Chip


<font size=-1>[ This Message was edited by: Chip on 2001-12-17 18:04 ]</font>

ToSeek
2001-Dec-17, 11:10 PM
On 2001-12-17 18:02, Chip wrote:

Wow! Will that mean they'll be able to resolve those tiny, extremely remote - hard to see red smudges (sometimes obtained with Hubble by using gravitational lensing,) into recognizable shapes?



Does this answer your question?:

http://acs.pha.jhu.edu/science/gallery/simulations/poster/poster7.1-sqrt-512.png

(May need Quicktime plugin to view.)

The Bad Astronomer
2001-Dec-18, 03:52 AM
On 2001-12-17 18:02, Chip wrote:
Will that mean they'll be able to resolve those tiny, extremely remote - hard to see red smudges [...] into recognizable shapes?


No, it doesn't. The resolution isn't any better than what has been done before. However, ACS is both more sensitive (it can see fainter objects in a shorter exposure) and sees a bigger area on the sky. Either way helps, and both together make it a powerful instrument. I just emailed a friend of mine who will be using it once it's installed, and he mentioned it should get down to magnitudes of fainter 30. The faintest objects ever seen by HST are about 30, so this thing will see those objects, and more of them, because it captures a larger area on the sky. Pretty cool. I can't wait to see teh images, and I don't envy the folks who have to analyze that much data...

ToSeek
2001-Dec-18, 01:09 PM
On 2001-12-17 22:52, The Bad Astronomer wrote:
The resolution isn't any better than what has been done before.


Is WFC3 going to be any better, or are the instruments already at about the limit of what HST can resolve?

Chip
2001-Dec-18, 10:30 PM
On 2001-12-17 22:52, The Bad Astronomer wrote:
The faintest objects ever seen by HST are about 30, so this thing will see those objects, and more of them, because it captures a larger area on the sky.


Understood. Are those HST objects at 30 the "red smudges" I referred too? Some of them seem just too small and/or too far away to resolve much more than they do. And on some Hubble pictures, after they process out cosmic rays, noise, etc...what are those sources that resolve into a single dull reddish pixel?

Can they take a spectrum of an image that remote?

Chip

<font size=-1>[ This Message was edited by: Chip on 2001-12-18 17:36 ]</font>

The Bad Astronomer
2001-Dec-18, 11:27 PM
Are those HST objects at 30 the "red smudges" I referred too?


I don't think so. The faintest stuff was seen by STIS, and the images weren't ever shown in color. The dimmest stuff was seen in the Deep Field South. You can find the images on the Hubble website.



what are those sources that resolve into a single dull reddish pixel?


That's a fine question. If you can answer it, publish! /phpBB/images/smiles/icon_wink.gif



Can they take a spectrum of an image that remote?

Not yet. When you take a spectrum, you take the light from a source and physical spread it out over a row of pixels. That dims the light per pixel by a huge amount (in STIS, the rows were 1024 pixels long, so each pixel had about 0.001 times as much in it as a single pixel would). Since these objects are faint to begin with, spectra are that much harder. The Next Generation Space Telescope may fair better. Try the NGST website (http://ngst.gsfc.nasa.gov).

[/quote]

Chip
2001-Dec-19, 12:29 AM
Thank you for the information! Great website link! /phpBB/images/smiles/icon_biggrin.gif

I asked: "Can they take a spectrum of an image that remote?"

You answered: "Not yet. When you take a spectrum, you take the light from a source and physical spread it out over a row of pixels. That dims the light per pixel by a huge amount (in STIS, the rows were 1024 pixels long, so each pixel had about 0.001 times as much in it as a single pixel would). Since these objects are faint to begin with, spectra are that much harder. The Next Generation Space Telescope may fair better. Try the NGST website (http://ngst.gsfc.nasa.gov)."

Chip:
Thanks again for the link. I wondered: What if someone took images of a very remote object that was only one, (or a few) pixels, and periodically imaged the same object over time, collecting a series of pixel images of the same object. (Perhaps collecting variations in "brightness" - or "less dimness" in the case of these impossibly dim objects.) Then, they arranged these repeated pixel images into a row within a computer file to create a sum over history translation of enough repeated pixels to create an artificial spectrum? The pseudo-spectrum might contain some scant information derived (i.e. squeezed) out of the cumulative repeated pixels of the same source, collected over a very along time.

Don't they already do stuff similar to this, but with more data to work with?

Anyway, Happy Holidays to all,

Chip

<font size=-1>[ This Message was edited by: Chip on 2001-12-18 19:30 ]</font>