PDA

View Full Version : Herschel space observatory is operational



Gigabyte
2009-Jun-22, 09:26 PM
http://news.bbc.co.uk/1/hi/sci/tech/8110345.stm

http://www.esa.int/SPECIALS/Herschel/SEM76A0P0WF_0.html

(If there already is a topic about this, pleeze tell me where and delete this one)

NEOWatcher
2009-Jun-23, 12:01 PM
(If there already is a topic about this, pleeze tell me where and delete this one)

That depends on how narrow your bandwith is for the concept of "topic".
There are several in UT Stories about Herschel, including the first observation story... but sometimes these tend to lose visibility with new topics coming in.

ToSeek
2009-Jul-10, 11:05 PM
Herschel images promise bright future (http://www.eurekalert.org/pub_releases/2009-07/esa-hip071009.php)


Herschel has carried out the first test observations with all its instruments, with spectacular results. Galaxies, star-forming regions and dying stars comprised the telescope's first targets. The instruments provided spectacular data at their first attempt, finding water, carbon and revealing dozens of distant galaxies.

These observations show that Herschel's instruments are working beyond expectations. They promise a mission of rich discoveries for waiting astronomers.

http://www.eurekalert.org/multimedia/pub/web/15261_web.jpg

R.A.F.
2009-Jul-10, 11:36 PM
You can actually see the spiral arms in that image...amazing!

tdvance
2009-Jul-11, 12:23 AM
I'd think seeing the spiral arms is not the amazing part, as Google turns up plenty of visible light pro and amateur photos (including one with a 500mm telephoto lens instead of a scope) of M74 with visible spiral arms.

Of course, spiral arms at 250 microns (hmm-that's way into the infrared I believe) might be something.

Tuckerfan
2009-Jul-11, 12:44 AM
Herschel images promise bright future (http://www.eurekalert.org/pub_releases/2009-07/esa-hip071009.php)



http://www.eurekalert.org/multimedia/pub/web/15261_web.jpg

Its Sauron! :eek:

ngc3314
2009-Jul-11, 03:36 PM
Of course, spiral arms at 250 microns (hmm-that's way into the infrared I believe) might be something.

Yeah - it's not that the dust in the arms wasn't expected to emit when heated by starlight, but this is the first instrument in the far-IR (this one goes out to a quarter millimeter wavelength!) with resolution much better than an arcminute, and thus able to map this structure out in any but the nearest galaxies. The Spitzer comparison shows a lot of the potential in going to Herschel's 3.5m mirror (versus 0.6-0.9 for its predecessors IRAS, ISO, Akari, and Spitzer).

George
2009-Jul-14, 02:42 AM
Yeah - it's not that the dust in the arms wasn't expected to emit when heated by starlight, but this is the first instrument in the far-IR (this one goes out to a quarter millimeter wavelength!) with resolution much better than an arcminute, and thus able to map this structure out in any but the nearest galaxies. The Spitzer comparison shows a lot of the potential in going to Herschel's 3.5m mirror (versus 0.6-0.9 for its predecessors IRAS, ISO, Akari, and Spitzer).
Is it really only near an arcminute in resolution? [How much better?] That won't reveal much, will it?

StupendousMan
2009-Jul-14, 04:12 AM
Is it really only near an arcminute in resolution? [How much better?] That won't reveal much, will it?

Work it out: the diffraction limit of a telescope is
approximately theta = lambda / D, where
"theta" is an angle in radians, "lambda" is the
wavelength, and "D" is the diameter of the telescope.

In this case, "lambda" = 250 microns = 250 x 10^(-6) meters,
and "D" = 3.5 meters, so theta = 7 x 10^(-5) radians.
That's about 0.25 arcminutes.

Will it reveal much? That depends on your point of view,
I suppose. It represents a factor of five or so improvement
in resolution at these wavelengths.

George
2009-Jul-15, 03:06 AM
That's about 0.25 arcminutes.

Thanks, StupendousMan. I was hoping for better, but feared the diffraction limit might make the resolution as bad as was stated.

Inner regions (50 AU radius) of stellar accretion disks will not have any resolutions (1 pixel at about 20 lyrs.)

But, I'm not complaining, really, as the big stuff will look great!

antoniseb
2009-Jul-15, 10:44 AM
As I understand it, the JWST will only go down to 28 microns, so that deep IR won't be there, but it will give much sharper angular precision.

BTW at that kind of wavelength Herschal will too.

ngc3314
2009-Jul-16, 11:41 AM
As I understand it, the JWST will only go down to 28 microns, so that deep IR won't be there, but it will give much sharper angular precision.

BTW at that kind of wavelength Herschal will too.

Best I can find, Herschel has instruments working from 57-670 microns, so there's no wavelength overlap. Herschel's mirror wouldn't be diffraction-limited at short wavelengths with that seamed construction. Getting the mirror quality for segments to be operated at cryogenic temperatures is one of the reasons JWST is so expensive (and even so, they've given up working for genuinely diffraction-limited images short of about 2.0 microns, and it has no detectors that work shortward of 0.6 or so). Still - diffraction-limited images from a 6.m aperture all the time at 2 microns, with the thousandsfold sensitivity gains from getting to space and chilling the instrument. Mouth-watering.

01101001
2009-Dec-17, 02:51 AM
Operating away...

ESA: OSHI, Online Showcase of Herschel Images, latest (http://oshi.esa.int/#list=/images.html;jsessionid=2D8255F58BC979FBF4C933878B5 12D98?q=latest)

George
2009-Dec-17, 04:02 AM
Nice!!!