Don't know where else to post it, so...

http://www.esa.int/esaCP/SEMV128X9DE_index_0.html


on the new infrared space telescope Herschel.

some news on a new space telescope

ESA's next-generation infrared observatory, due to be launched in 2007, follows in a grand tradition. In the 1980s, the US-Dutch-British satellite IRAS inaugurated infrared space astronomy by mapping 250 000 cosmic infrared sources and large areas of extended emission. ESA's ISO, launched in 1995, pursued this exploration providing a wealth of science data until May 1998, well beyond its nominal 18-month lifetime.
Currently NASA's Spitzer Space Telescope is in operation going further down the ISO track. Software tools developed for Spitzer will be used by Herschel that, in turn, will be pushing back the frontiers of infrared astronomy with its larger telescope and ability to observe at longer wavelengths.
http://sci.esa.int/science-e/www/are...cfm?fareaid=16
http://www.thespacesite.com/260905_h...servatory.html
http://www.physorg.com/news6754.html
The largest telescope mirror ever built for space, due to be launched on board ESA’s Herschel spacecraft in 2007, has completed its assembly and first testing phase.

so this will be up before JWST ?

Yes, by about six years.

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Everything I need to know I learned through Googling.

I believe that Planck and Herschel will be launched together (to save money). Originally, I was very upset about this misguided frugality because I felt Planck was much too important to take chances with. I really didn't care much about Herschel - I didn't think it would tell us anything basic. I thought it would just do some grunt work cataloguing young galaxies without much theoretical significance. Well, reality keeps amazing and delighting us. There may be some anomalies to resolve in the early nurseries. Now I'm really excited about Herschel! Launching Herschel and Planck together still makes me nervous. I hope everything proceeds successfully. Hershel and Planck should both be a lot of fun!

EADS Atrium has completed assembly of the mirror for the European Space Agency's Herschel space telescope. This milestone moves Herschel a step closer to its late 2007 launch date.

What I don't get, is why are we getting so upset about Hubble being allowed to go out of service? Recent adpative optics packages for the Keck II telescope have made it as good as a space based telescope. You remember the rotational images Hubble got of Ceres a month or two ago? About a year ago Keck II used adaptive optics to do the very same thing - and it achieved better detail. I have the pictures.

Compare...

Rotational images of asteroid 1 Ceres as achieved by Christophe Dumas and his team using Keck II with AO. A year or so ago.
http://s1.simpload.com/10034341d7edcf588.jpg

Very recent rotational images using Hubble.
http://s1.simpload.com/10034341d866aab89.jpg

Note that in the Keck II images, you can clearly see large craters, large dark spots, etc, traversing the planetoid. The only thing you can see in the Hubble images is a big white spot. Conclusion: The year old Keck images are way better than the recent Hubble images.

So, I think that Hubble is great, just like all of us. I think it is an incredible piece of technology. But, its time has come and gone. We can now get equal, if not far better, performance out of ground based systems. And what with Herschel going up in 2007, I really dont see the need for Hubble. Especially because of the price tag of keeping it running.

Does anyone have any interesting information on Herschel? I've heard the latest technology was used to create the mirror, and it is half again as big as Hubbles. Just exactly how much more powerful will it be over Hubble? How long will it be able to function?

---Vil.

Unfortunately, the Keck scopes can't look at one point in the sky for 30 hours straight. My understanding is that the strength of the Hubble was not its resolving power but it's light grasp from being able to focus for periods that the Earth's rotation would not allow ground-based telescopes to match.

I don't know that there's really a great hue-and-cry over the decommissioning of the Hubble per-se. There are twinges of nostalgia among its strongest supporters, and there is also the fact that it is maintainable, repairable, and upgradeable - aspects that I understand will be lost in the next generation of space-borne telescopes. I wonder what kind of media will be available the day after scientists announce that the Herschel telescope's mirror cracked during liftoff and the resulting images will only be useful for X and Y, not Z as orginally planned.

The only reason the Hubble is going is the price-tag you mentioned. In terms of capability, it is still an immensely useful instrument, and it could (theoretically) serve us for another few decades scanning the entire sky to the depth that it has, thus far, only examined small portions. Unfortunately, it does so at a cost that is, pardon the pun, astronomical.

Sincerely,
Derrick Baumer

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If I'm wrong, you probably asked me the wrong question.

Thank you, I had never thought of that.

I was always wondering what the big fuss over space based telescopes was about. Now it makes sense. While a ground based telescope could have far more massive optics, and indeed be able to resolve objects with greater detail, it would never be able to get the same views of galaxies and nebulas that a space based telescope could.

I figured that Herschel was not meant to be serviced, and thats why I question its lifespan. If we can never go and patch it up, and give it new equipment or batteries, I wonder what its projected lifespan will be? Probably far less than what the hubble has already served.

---Vil.

Keck scopes are wonderful they continue to make great observations and great discoveries in space


However - Adaptive optics are totally over-sold and over-rated by ground based guys that say it is a magic tool or wrongly fear funding may taken away be put into space, 'adapative optics'
is not some magic wand, otherwise people wouldn't be lauching space telescopes and people wouln't be talking about saving Hubble. Space telescope will remain a very important part of science and go out in space for a long time to come.

Telescopes on the ground have the Earth blocking much of their view and the night and day sequence dispurts viewing

Ground based scopes can't image the atmosphere of exo-planets..something that may soon be done by NASA's TPF and ESA's Darwin...
ground based adaptive optics can't do sqaut here we need a space mission for this.

Our atmosphere blocks much of the spectrum, we have a window in visible light, almost no real UV, a small window in infrared IR, and a big window Radio frequency
adaptive optics can't view a spectrum that is already invisble from Earth.

Oftentimes bad weather plays a role, this is perhaps why scopes like Chandra XMM-Newton, Spitzer can do better work on missions like Deep impact.

There are also issues of protection, vandalism, theft, terrorism and security to deal with on earth based observatories

Ground scopes can not probe 'Blind Spot' there could be many potentially hazardous asteroids (PHAs) out there but there is a notorious 'blind spot' that telescopes on Earth can never peer into.

there are many other reasons aswell why space telescopes are so important, some of which seohtu mentioned

Manchurian, if you have a moment, could you elaborate on the blind spot you refer to? I imagine the sun and its environs would qualify.. regardless of the Earth's position around the sun, looking toward the sun would be detrimental to the Keck's cameras, for instance <wink>. Or is there another aspect I haven't yet stumbled upon?

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If I'm wrong, you probably asked me the wrong question.

Europe's Gaia will be checking it, region of space inside Earth's orbit, towards the Sun. From Earth, astronomical observations close to the Sun are almost impossible because it means observing during the daytime when only the brightest celestial objects stand
http://www.bautforum.com/showthread....703#post438703
The Gaia spacecraft will be ideally situated to probe the asteroid blind spot between the Sun and Earth. Asteroid 2002 EM7, which passed close by the Earth was one such object and was only detected after it crossed Earth's orbit to appear briefly in the night sky, before it crossed back into the glare of the Sun

Posts such as there belong in the Astronomy section, which is where it now is!

Merged our three threads about Herschel into one, apologies for any confusion.

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Everything I need to know I learned through Googling.

Some reasons the Hubble users are such fans include:

It has diffraction-limited resolution, and not just resolution but the whole point-spread function (PSF, what an unresolved star looks like) is very close to the theoretical limit all the way from 110-2200 nm. Below 300 nm the ozone (still) blocks the light on the ground, and adaptive optics (a) work much less well in the visible than the near-IR and (2) give amazingly sharp image cores but substantial and time-variable halos, which take a lot of work to calibrate and (as far as I know) set the precision limit on such applications as quasar host galaxies.

This means that, for example, HST could (with the loss of STIS, that's in the past tense barring a miracle with the next shuttle flight) set its spectrograph aperture 0.3 arcseconds from a quasar core and get a measurement with a small and pre-calculable contribution from the quasar, which AO still can't do. One amazing observation in this vein was measuring the differential Doppler shift from opposite limbs of Betelgeuse to drive its direction of rotation (the bright spot in the HST UV images is around its north pole).

Long uninterrupted viewing windows are a rarity for Hubble, happening only for the piece of sky close to the instantaneous poles of its orbit (which is why Chandtra and XMM-Newton are in such high orbits) - the deep fields were composited from large numbers of single exposures. This advantage of space observations matters only for certain kinds of variable objects where there is an aliasing effect from daily, monthly, or annual interruptions (and this turned out to matter for the key project on Cepheid variables - they could schedule for much more uniform efficiency of detection if the periods of observation need not strobe against the Moon's phases).

Furthermore, the sky background is lower from space than from the ground at all wavelength ranges. This isn't a big deal in green light (the V-band brightness is only twice as high at a good dark site), but becomes more important blueward, and especially into the near-IR, where the gain can be factors of thousands. Thus 10-m telescopes on the ground can outdo HST ony by having 16x tyhe loight grasp plus spending a good deal longer on an observation. (Note that the diffraction limit of HST reaches 0.3 arcseconds at 2200 nm, something which several large telescopes can routinely sneak up on without AO - there is an extensive white paper available from www.stsci.edu detailing the tradeoffs of each approach). This is one driver for JWST and Herschel.

An additional issue is that HST time is allocated from applicants worldwide, and publicly available AO systems have lagged greatly. The only such system available for applications (last I heard, anyway) from any US astronomer is Hokupa'a on Gemini-N, while Keck is available to applicants from UC, Caltech, UH, and NASA-supported work on planetary systems (plus any sufficiently close collaborators, etc.). ESO has done a better job, with high-quality systems tested on their 3.6m and implemented at the VLT. (This also means that astronomers in the cultural outback have more trouble keeping up with the capabilities of AO systems). None of this is meant to belittle the enormous technical achievements in AO, by the way - my nominee for "coolest thing ever done at Keck" would have to be Andrea Ghez' group measuring the orbits of stars around the Galactic Center and basically nailing the case for a massive black hole (work which was largely confirmed at almost the same time by Genzel's group using the VLT).

Herschel Space Observatory
http://sci.esa.int/science-e/www/obj...objectid=31361

It will be the first space observatory covering the full far infrared and sub-millimetre waveband, and its telescope will have the largest mirror ever deployed in space. It will be located 1.5 million kilometres away from Earth at the second Lagrange point of the Earth-Sun system. Herschel's three and a half metre mirror will collect the light from distant and poorly known objects, such as newborn galaxies thousands of millions of light-years away...

30 Nov 2005 10:16
http://sci.esa.int/science-e/www/obj...objectid=38340
The assembly of the Herschel Structural and Thermal Qualification model has been completed in ESTEC. The two main modules constituting the satellite: the payload module and the service module were joined together for the first time last week. After completion of dedicated thermal tests on each module, the assembled satellite will soon undergo mechanical vibration and shock tests to complete the environmental qualification campaign.

European Space Agency and the French company Arianespace signed a contract for the provision of an Ariane 5 ECA launcher for the Herschel and Planck spacecraft.
http://www.esa.int/esaCP/SEM8S2WLWFE_index_0.html
Herschel will study the birth of galaxies and stars and Planck the very early history of the Universe.

Herschel Ready for Mechanical Vibration and Shock Tests
http://sci.esa.int/science-e/www/obj...objectid=38735
01 Feb 2006 16:54
The completed Herschel Structural and Thermal Qualification model satellite has been mounted onto the HYDRA platform in preparation for mechanical vibration and shock tests to complete the environmental qualification campaign


Here is that other Planck mission -
http://www.spacemart.com/reports/Pla...st_Center.html
Planck is the first European mission to study the birth of the Universe, Planck will look back at the dawn of time, close to the Big Bang, and will observe the most ancient radiation in the Universe, known as the 'cosmic microwave background'. More than 40 European and some US scientific institutes will participate in the construction of the instruments. An Ariane-5 launcher will carry Planck into space in July 2007. Saab Ericson Space in Sweden will give the Attitude Control Computer its Central Data Management Unit, Ametek United States will give Planck the Reaction Control System's Latch Valves, Northrop Grumman United States provides the Attitude Control Management System - Gyroscope, Datasat United Kingdom will provide the Electrical Engineering Support, Alcatel Espacio in Spain will build the Radio Frequency Distribution Network's X-Band Transponder......
Planck Science Team Home
http://www.rssd.esa.int/index.php?project=Planck
For reasons of cost effectiveness, ESA has decided to launch Planck together with Herschel, an infrared space telescope. The two spacecraft will separate soon after launch and will operate independently.

Testing of Herschel Structural Model
http://sci.esa.int/science-e/www/obj...objectid=38899
06 Mar 2006 15:13
The Herschel Structural Model spacecraft is being prepared for a series of qualification tests in the acoustic test chamber, LEAF, in ESTEC.

Herschel Space Observatory
http://www.ipac.caltech.edu/Herschel/
The Herschel Space Observatory is th