October 2006 Archives

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My bookmarks for this week

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  • Catalyst: Celestial Navigation - ABC TV Science
    Long before Europeans were exploring the world’s oceans, Polynesian sailors had successfully landed upon just about every scrap of earth in the Pacific – without any conventional navigational tools.
    Tagged as: [astronomy science australia]

  • What is the point of astronomy? | Astronomy Blog
    Why do we pay for space science/astronomy?
    Tagged as: [science astronomy]

  • Transit of Mercury, 9 November 2006
    On the morning of Thursday, November 9, Mercury will transit the Sun as seen from Australia, New Zealand and parts of the Pacific, East Asia and the Americas.
    Tagged as: [astronomy science planets]

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MRO looks at Opportunity

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Rover Opportunity from aboveThis was posted as one of my "links for the week", but it's cool enough to mention on its own: the new Mars Reconnaissance Orbiter is taking very high resolution images of the martian surface since reaching its final orbit; the pictures show a few centimeters per pixel. That's about as good as the best images of Earth you can see in Google Maps.

And one of the recent images shows rover Opportunity standing by the rim of Victoria crater. The rover is clearly visible, and you can even see the shadow of the camera mast and the tracks it left while getting there. You can see a detail of the image here; click on it to see the full image and the press release.

The ability of seeing the same terrain from two different view points will be very useful to scientists, both in analysing science results and in plotting future movements of the rovers. Come to think of it, it's quite possible that the MRO will be able to find the ill-fated Beagle, the British lander that was lost in late 2003, which may help pin-point the causes of the loss.

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NAGging

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Last night was this month's meeting of the NAG, about which I wrote here. Differently from the other months, this meeting did not have a theme; it was the "nothing in particular" meeting.

Because of that, we spent most of the time outside, enjoying one of the few clear nights of the last few weeks. Unfortunately, the almost-full moon made sure that the only "interesting" thing to look at was, well, the moon (note to self: looking at the full moon with binoculars after allowing your eyes to adapt to the dark will ruin your night vision for several minutes).

There were a few small telescopes around, plus the ASV's large 20-inch; plus, several people (myself included) had their binoculars at hand. The only visible planet was Jupiter, but it was very low in the sky and it dropped off behind the trees before the 20-inch was set-up (and cooled down). Uranus and Neptune were up as well, but in the same general direction of the moon and, therefore, not visible.

One highlight of the night was seeing the ISS; it showed up low in the southwestern sky and disappeared when it was starting to set in the northeast, after flying almost directly above us and staying clearly visible (as a bright orange dot) for over two minutes. This was quickly followed by a 0-magnitude Iridium flare, followed soon after by a spectacular -3-magnitude one, with an unknown satellite doing approximately the same path of the ISS minutes later. It's definitely getting crowded up there. (heavens-above.com will tell you when the ISS and Iridium flares are visible from your location, and how to find them)

What are Iridium flares?

Satellite flares, in general, are bright flashes of light visible from the ground when the Sun light reflects off satellites flying above. The Iridium phone satellites, in particular, generate very bright flares due to their format; the flashes can go up to magnitude -8, and can be visible in bright daylight if you know where to look at. Flares are very localised events; the "spot" of light created on the ground is some 10km wide, so you need to know your location (latitude/longitude) failry precisely in order to find out about them. Google Maps can help with that.

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This page is an archive of entries from October 2006 listed from newest to oldest.

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