Buried in data ...

[Andrew Bennett <andrew.bennett@ns.sympatico.ca>]

The final load of grapes went down the driveway
today. Maybe I can start digging out from under
that stack of Tom's CDs.

About the time the truck left, the post arrived
with "Astronomy & Geophysics." A long article on
the proposed GAIA system to be launched in 10 years.
Highlights:

"The main focal plane assembly employs CCD technology,
with about 250 CCDs ... per focal plane [3 of them]." 
" ... an integration time of ~0.9 s per CCD"

Now that's a data rate. Even if the CCDs are "only"
4 Mpixels @ 16 bits. Um! Multi GBytes per second.

" ... an average of 1 Mbit of data per second is
returned ... throughout the five-year mission."

So there is, to put it mildly, a fair bit of
processing going on up there: 

"On-board object detection will ensure that variable
stars, supernovae, transient sources, microlensed events
and minor planets will all be detected and catalogued
to this faint limit [V = 20 mag]."

And what does this get you? 10^9 targets seen 100 times 
each. Positions to 0.01 mas at M = 15. That's 100x better 
than Hipparcos while going 5 mags deeper. The system is
aimed at astrometry but does photometry too ... as an
accidental by-product.

And that's just a fraction. Try astro.estec.esa.nl/GAIA

Andrew Bennett, Avondale Vineyard