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Hubble's Deepest Pictures Yet
MrBook2 writes "NASA have just released the Ultra Deep Field (UDF). This image took 800 exposures and clocked in at 11.3 days (!) of exposure time. This image is deeper than the Hubble Deep Field which has yielded a vast amount of knowledge. So, why exactly was it that NASA wanted to scrap the Hubble?"
So, why exactly was it that NASA wanted to scrap the Hubble?
Because thanks to adaptive optics, it is now possible to get very close to hubble's resolution with Earth-based telescopes. Thus, it is much, much cheaper to use those ground-based scopes.
Because we don't have a really huge budget for this sort of thing, and all the money that goes into Hubble could be used on a newer, better space based scope.
It goes back to an era quite a bit earlier than the earlier deep-fields--about 400 and 800 million years after the big bang--and they are noticing quite a bit more chaos in the early universe, as the first galaxies were forming:
So, they are already seeing oddball things that they didn't see in earlier deep-field images.
The image as presented is actually a composite of two images, one taken in visible light and one taken in near-infrared. This allows the image to show details that would have normally been obscurred by dust.
HCG 50a = 2MASX J11170638+5455016
11h17m06.4s +54d55m02s
Actually, a congressman from Colorado is trying to get a commitee together to determine the fate of the Hubble, so the decision is not solely on the director of NASA. This could mean life for the Hubble.
I submitted the 'save the hubble' story a couple days ago and was turned down.
Good quote, too many chars. Seriously, the slashdot 120 char limit sucks!
They are not scrapping Hubble because of cost. The NASA Administrator stated that the reason was due to "the risk to the astronauts on a Hubble mission and President Bush's plans to send humans to the moon, Mars and beyond as the reason for NASA's change of focus." In fact, the planned upgrade has been built, tested and (most importantly) PAID FOR. It's just setting there waiting to be taking to the telescope and installed.
Are you Corn Fed?
The big reason I have heard for discontinuing mantanence on the Hubble is it's orbit. If a shuttle goes out to do maintanence and is damaged, the orbit makes it impossible to reach the ISS and difficult to do anything else to save the crew.
This signiture copied from somewhere.
http://savethehubble.org/
If they are willing to take the risk to finish ISS, there is no good reason not to fix Hubble.
Write your congressman.
Blaze a trail to the New World
NASA intends to eventually replace the Hubble with the James Webb Space Telescope:
The James Webb Space Telescope (JWST) is an orbiting infrared observatory that will take the place of the Hubble Space Telescope at the end of this decade. It will study the Universe at the important but previously unobserved epoch of galaxy formation. It will peer through dust to witness the birth of stars and planetary systems similar to our own. And using JWST, scientists hope to get a better understanding of the intriguing dark matter problem. The JWST is also a key element in NASA's Origins Program. So, between the JWST and the terrestrial observatories using new adaptive optic technologies, over the long haul it makes better sense to re-allocate our scarce space resources not only on these projects, but also towards the new goals announced by GWB. Remember that Bush hardly increased NASA's budget, so they cannot afford to do everything at once.
More facts about the JWST as it stands now.
Proposed Launch Date: August 2011
Proposed Launch Vehicle: Ariane 5
Mission Duration: 5 - 10 years
Total payload mass: Approx 6200 kg, including observatory, on-orbit consumables and launch vehicle adaptor.
Diameter of primary Mirror: ~6.5 m (21.3 ft)
Clear aperture of primary Mirror: 25 m2
Primary mirror material: beryllium
Mass of primary mirror: about one-third as much as Hubble's
Focal length: TBD
Number of primary mirror segments: 18
Optical resolution: ~0.1 arc-seconds
Wavelength coverage: 0.6 - 28 microns
Size of sun shield: ~22 m x 10 m (72 ft x 33 ft)
Orbit: 1.5 million km from Earth at L2 Point
Operating Temperature: Cost: $824.8 million
Note that it is planned to launch the JWST using an Arianne rocket, which is far cheaper, and can also get the device to the L2 point. Yes, the shuttle could launch JWST into LEO (low earth orbit) but it would then have to travel up on an additional rocket. Seems like they have accounted for this and are going to use a cheaper expendable vehicle to do the job.
The one problem with that is that the JWST is an infrared and near infrared telescope. 0.6 micron = 600 nm = red light. This won't give any coverage to the rest of the optical spectrum (~380-600 nm).
You have a short memory.
Well, his still considerably better than this AC's.
The mirror is seriously messed up. It has been corrected with a lens, but the quality is still rather less than it should have had.
And, yet, still better than anything else we have today or will have in the next 20 years. There is no Hubble replacement on the way, and while earth based scopes can replace some of its functionality, they can't replace all of it.
The James Webb scope will have a much larger mirror, much faster camera
And is an IR only telescope. It does not have the range of instruments that Hubble has. In particular, it lacks any realistic UV sensors.
could be put on an orbit to allow evacuating the shuttle crew to Fred
I'm not even going to try and guess what "Fred" is, but JW isn't going to be in an orbit allowing the shuttle to do anything with. The JW Scope is going to be stationed at the L2 point, considerably farther than where the shuttle can go. If something goes wrong with the scope -- thank you for playing, goodnight. It's unserviceable, at least by anything we have now or in the forseeable future. Damn well better not have a problem with failing gyros, mirror irregularities, or anything else. Because if it does then we've put all our eggs in one basket. By the time that JW is launched and in position (late 2010 to 2012) Hubble will be unrepairable. Unless we spend the time, money, and risk on a single shuttle mission to repair and upgrade it.
You can argue all you please about how Hubble is out-of-date and needs cancellation, but the real experts will disagree with you. Astronomers are quite irate about the Hubble's cancellation, and rightly so. Politicians should not dictate how NASA spends its paltry budget - and doubly so in an election year when your poll numbers are looking grim.
Sean O'Keefe was picked for the head of NASA precisely because he has a reputation as a budget cutter. The man knows *nothing* about space science.
But don't take my word for this. The American Astronomical Society - an organization that includes essentially all the professional astronomers in America, and rarely if ever takes a political stand - released a statement pleading to reconsider the cancellation:
AAS's cancellation statement
I believe there's a statement from the UK's Royal Astronomical Society there, too.
This is absolutely 100% false. The Hubble UDF image was taken over the span of several months, not over 11.3 days of consecutive orbits. Stacking images from earthbound telescopes taken over several different days/months is a standard astronomical practice. No special equipment (i.e. a worldwide distributed network of telescopes) is required to do this.
As for not having the versatility of Hubble -- there are many terrestrial observatories that are far more versatile (and accessible!) than HST. It all depends on the sort of observing you're doing.
(2) The atmosphere blocks alot of the UV band, in particular the hydrogen 1 Lyman-alpha line. That's the brighest emission line of the most common element in the universe. With a wavelength of about 121.6nm (unredshifted), not much of it punches through the atmosphere. Check out this for a primer on what's so important about the lyman alpha line.
--- Often in error; never in doubt!
It's a good thought, but ozone holes are really ozone depletions, and they still rule out sensitive UV measurement. That, and the holes are at the poles, and so you're limited to the amount of sky you can look at.
Dr Fish
Please read some of the posts by astronomers (including me) in this story and any other HST story. This is absolutely untrue. Yes, AO does allow ground-based astronomers to take high angular resolution images comparable to the quality of Hubble. However, the science that you can get from AO images does not compare to the science you can get out of Hubble images. AO is still too limited in many ways, and there is no way it will ever overcome some of the limitations. THE FACT IS THAT ULTRAVIOLET ASTRONOMY IS IMPOSSIBLE FROM THE GROUND! No AO telescope can observe in the UV, which Hubble can. This makes impossible many topics in Quasar research, interstellar and intergalactic medium research, hot star research, and a zillion other fields that I can't think of off the top of my head.
It was politics, ie Bush's men on mars initiative, that led to O'Keefe's decision to cancel Hubble's servicing mission. Let's not give up now that O'Keefe is starting to feel some political pressure. At http://SaveHubble.org we are working on polling all of congress. How about some of you slashdot readers give us a hand contacting them?