My Assistant
| Posted on: Oct 30 2008, 11:28 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
This is not a specific criticism, but a general one; I know the reasons for it have to be lack of personnel or money, and hopefully not lack of planning or foresight. I can't understand why this spare was not dragged out of storage periodically (maybe annually) and tested so that any problems could be identified & resolved long before it was needed. Oh, they have dragged it out a couple of times (but not for verification but to test various procedures before uplinking commands to live flight hardware.) It gets worse: on such occasions, it was noted that faults occurred with the flight spare during such operations... Repair won't be easy: you're dealing with a box full of long-obsolete ICs. Perhaps with unlimited time and resources, they could have taken the modern approach of an all-software data handling system running on general-purpose hardware, just in case HST did not live up to its original design life of 15 years. |
| Forum: Telescopic Observations · Post Preview: #129801 · Replies: 28 · Views: 20807 |
| Posted on: Oct 18 2008, 12:33 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
Does anyone know which CCD the HST is using? Originally it was launched with a 2.56 million pixel CCD HST has numerous CCDs in its instruments. I suppose you're referring to WF/PC-1? It was really a set of 8 CCDs (4 per plane) with a resolution of 800x800 pixels each. Here's a list of the detectors currently onboard: CODE ACS WFPC2 NICMOS STIS Wavelength range (nm) WFC: 370-1100 115-1100 800-2500 FUV-MAMA:115-170 HRC: 200-1100 NUV-MAMA: 170-310 SBC: 115-170 CCD: 200-1100 Detector(s) SITe CCDs, MAMA Loral CCDs HgCdTe CCD, MAMAs Image format 2×2048×4096 4×800×800 256×256 1024×1024 1024×1024 256×256 1024×1024 1024×1024 256×256 1024×1024 |
| Forum: Telescopic Observations · Post Preview: #128918 · Replies: 28 · Views: 20807 |
| Posted on: Oct 10 2008, 04:51 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
I wonder if they can transition to MRO, which is typically an hour later, or even more MEX relays. There was mention of MRO in a recent Oppy update (below), so that is perhaps what they are planning to do. QUOTE On sol 1644 (Sept. 7, 2009), Opportunity relayed data at UHF frequencies to NASA's Mars Reconnaisance Orbiter (MRO). Typically, the rover sends data to NASA's Odyssey orbiter for transmission to Earth. Once a month, Opportunity is relaying data to the Mars Reconnaissance Orbiter in preparation for using it more in the future. |
| Forum: Tech, General and Imagery · Post Preview: #128395 · Replies: 1 · Views: 4571 |
| Posted on: Oct 8 2008, 10:15 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
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| Forum: Chit Chat · Post Preview: #128184 · Replies: 20 · Views: 14743 |
| Posted on: Sep 28 2008, 05:32 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
Yup, there's a team led by Peter Jenniskens (who regularly does this during meteor showers) going up. More details here: http://atv.seti.org/ |
| Forum: Exploration Strategy · Post Preview: #127046 · Replies: 222 · Views: 138859 |
| Posted on: Sep 23 2008, 05:47 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
Ulysses finds that the solar wind pressure and magnetic field strength is 20% lower than the previous solar cycle, and the lowest since such measurements began. Implications are that Voyager 1 and 2 could reach the heliopause sooner than predicted, if this trend continues. |
| Forum: Sun · Post Preview: #126606 · Replies: 77 · Views: 170570 |
| Posted on: Sep 22 2008, 10:32 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
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| Forum: Sun · Post Preview: #126523 · Replies: 77 · Views: 170570 |
| Posted on: Sep 16 2008, 09:22 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
Naively, I'd expect a brown dwarf to be mostly hydrogen and helium, with no icy or rocky core to speak of, but a planet -- even a giant planet -- formed in an accretion disk would be more like Jupiter or Saturn. My reasoning is that the heat of the star ought to push some of the hydrogen and helium out of the disk, making planets rather different from brown dwarves, even if they had the same mass. Spectrally, brown dwarfs appear to have similar composition to Jupiter (and even similar weather activity!) Bear in mind that the early solar nebula disk was 99% H and He compared to the heavy elements -- if the Sun had driven-off the H and He, you would not be able to build a Jupiter, which also shares the same H/He ratio as the Sun. If this is a binary system, it would be remarkable, as star-formation simulations are unable to produce systems with such extreme mass ratios. |
| Forum: Telescopic Observations · Post Preview: #126040 · Replies: 67 · Views: 57180 |
| Posted on: Sep 16 2008, 11:44 AM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
People can lose their Facebook account for the dumbest of reasons. A friend of mine lost over 150 friends in a recent Facebook crackdown. Their crime against humanity? They had an image of a dog as their profile picture... |
| Forum: Phoenix · Post Preview: #126017 · Replies: 32 · Views: 110752 |
| Posted on: Sep 16 2008, 11:34 AM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
I haven't read the paper in question, but presume it rules out such a case from the observables. Yes, the authors state: "...the spectrum of the companion confirms that it is very cool, showing important water vapor absorption on either sides of the H and K bands and strong CO band heads beyond 2.29 µm." |
| Forum: Telescopic Observations · Post Preview: #126016 · Replies: 67 · Views: 57180 |
| Posted on: Sep 16 2008, 11:32 AM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
Are there (or were there) other stars in the neighborhood? Perhaps this planet is a relic expelled from another solar system and captured? There are 82 stars nearby, but they estimate that the chances of an interloper are 1-in-30,000. Nevertheless, we really need follow-up proper motion studies to verify that this planet is truly bound to the star. |
| Forum: Telescopic Observations · Post Preview: #126015 · Replies: 67 · Views: 57180 |
| Posted on: Sep 10 2008, 09:09 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
The color accuracy of the latest SPVA-based panels are pretty decent, but they still have the drawback of high black levels, so I stick with CRTs. Choosing a monitor is a highly subjective thing; best to try to see the display in person before buying... |
| Forum: Chit Chat · Post Preview: #125702 · Replies: 6 · Views: 6518 |
| Posted on: Sep 7 2008, 01:44 AM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
The laser frequency comb was recently successfully tested at the VTT: http://www.eso.org/public/outreach/press-r...8/pr-26-08.html This is needed to build the next generation of spectrographs to enable detection of Earth-like planets, dark energy etc. The required accuracy really is quite astonishing: QUOTE In fact, they must be accurate to about one part in 30 billions - a feat equivalent to measuring the circumference of the Earth to about a millimetre! |
| Forum: Telescopic Observations · Post Preview: #125392 · Replies: 0 · Views: 2689 |
| Posted on: Sep 6 2008, 12:38 AM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
If we ever develop the technology to accelerate a spacecraft to 0.1c, one would hope we would also be able to slow-down from 0.1c at the other end. |
| Forum: Voyager and Pioneer · Post Preview: #125213 · Replies: 54 · Views: 81172 |
| Posted on: Sep 6 2008, 12:36 AM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
I never posted in that forum, but found it to be very useful in keeping up-to-date with the latest happenings in that area, so sad to see it go, too. With all the amazing things happening in the Solar System and the Universe, why anyone would burn their time discussing politics is beyond me... |
| Forum: Forum Management Topics · Post Preview: #125212 · Replies: 44 · Views: 151664 |
| Posted on: Sep 5 2008, 05:59 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
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| Forum: Telescopic Observations · Post Preview: #125182 · Replies: 4 · Views: 5442 |
| Posted on: Sep 1 2008, 05:54 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
I have never heard anything similar from reliable sources (i.e. anything but la Repubblica) . Any info? I recall reading in Science (or similar rag) that a team from JPL originally found 100,000 microbes per sq/m just a few months before launch, and thus requested a more aggressive sterilization program. |
| Forum: Phoenix · Post Preview: #124910 · Replies: 49 · Views: 56652 |
| Posted on: Sep 1 2008, 01:02 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
Yesterday, I spent three very pleasant hours walking eight dogs (and got paid for it!), and read a science paper on dark matter and 22 pages of the Cassini ISS handbook on my palmtop during the outing. Does that qualify me as a UMSFer? |
| Forum: Chit Chat · Post Preview: #124893 · Replies: 33 · Views: 30962 |
| Posted on: Sep 1 2008, 01:01 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
Observations of MACS J0025 supports findings of the Bullet Cluster, suggesting dark matter is collisionless: http://hubblesite.org/news/2008/32/ http://chandra.harvard.edu/photo/2008/macs/ The paper linked from Hubblesite dismisses MOND as being unable to explain the strong lensing effects and only limited success with explaining the weak lensing. |
| Forum: Telescopic Observations · Post Preview: #124892 · Replies: 4 · Views: 6259 |
| Posted on: Aug 28 2008, 12:00 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
If Doug takes a dark frame on the ground with the same equipment and the same camera settings, possibly cooling it a bit to have comparable thermal noise levels, it might be possible to compare noise densities or patterns in the images and check for any radiation effects. No need to cool the camera, as cosmic ray hits are very obvious -- they leave bright pixels or trails on the image, given a long-enough exposure. |
| Forum: Private Missions · Post Preview: #124614 · Replies: 141 · Views: 207151 |
| Posted on: Aug 27 2008, 02:01 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
Please accept a rain check from me; I'd very much like to join y'all, but with the equipment at my disposal, the best I could do would be a 720x576 screengrab from my S-VHS video camera -- not "reasonable quality" by today's standards. Be sure to give my best to Oppy. |
| Forum: Chit Chat · Post Preview: #124514 · Replies: 27 · Views: 18270 |
| Posted on: Aug 27 2008, 02:00 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
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| Forum: Dawn · Post Preview: #124513 · Replies: 285 · Views: 337413 |
| Posted on: Aug 26 2008, 06:27 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
NASA announces new name for GLAST: Fermi Gamma-ray Space Telescope http://www.nasa.gov/mission_pages/GLAST/ne...ings_media.html |
| Forum: Telescopic Observations · Post Preview: #124465 · Replies: 56 · Views: 60658 |
| Posted on: Aug 5 2008, 12:17 AM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
If they have a hard time interpreting their findings and agreeing on one story, it doesn't bode well for the peer review their conclusions are going to get. It isn't necessary for a science team to get their story straight before publishing papers in peer-reviewed journals. In fact, it is quite common for authors to speculate on the wide range of possibilities presented by the data. For example, in a paper that I recently read on extrasolar planets, the authors described their observations, and then went on to speculate (educated guesses based on the observed phenomena) as to whether the planet has an intrinsic or induced magnetic field (or perhaps none at all!) in order to explain the data. After 16 pages, they essentially said they weren't sure what the heck was going on and needed more data... |
| Forum: Phoenix · Post Preview: #122589 · Replies: 377 · Views: 2738428 |
| Posted on: Jul 30 2008, 10:00 PM | |
![]() Member ![]() ![]() ![]() Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
Stu, you owe me a new swear jar! |
| Forum: MRO 2005 · Post Preview: #121816 · Replies: 41 · Views: 35501 |
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