[LMB] Dragging Arecibo onto topic

Markus Baur baur at chello.at
Tue Nov 24 07:35:12 GMT 2020

Am 24.11.2020 um 01:01 schrieb Pouncer via Lois-Bujold:
> Markus Baur quotes, er, somebody, and responds:
> >> The far side of the moon is much better protected from Earth
> >>based radiations.   And the very slow rotation period of the
> >>moon makes it much, much easier to have super long exposures.
> >the slow rotation speed is both and advantage(as above) and a
> >curse, as it will take about 14 days (or longer, depending on
> >how much the telescope can steer away from zenith) until a
> >target can be observed again
> Both of which are completely true, and together represent a
> good argument for building several. Four, maybe.  One at the
> Lunar north pole; one at the leading edge of the equator,
> in the direction of orbit; one at the trailing edge; and one
> at the south pole. All just behind the horizon.  Just nearside
> those working locations there should (eventually will be) the
> Earth-side habitat where the people live and work and exchange
> text messages and cat videos with family and friends on Earth,
> and cables strung over the horizon to the telescopes receiving
> radio and radar reflections from, well, everywhere else. If the
> engineers come in under initial budget, maybe two more, at 60
> degree intervals.  So, six.  Or more.  Why not?

ultimately - yes ..

an arecibo design telescope as a pretty narrow field of view (arecibo 
has a 40° field of view - 20° off zenith in every direction) . so if we 
want to us use the moon as radio backstopm, but see the entire 180° sky 
hemisphere visible form there we would need about 10 telescops ..

> If you build several of anything the lessons learned from the
> earlier can be applied to the next. The later constructs will be
> better or cheaper or both. Unless you allow the military to
> design them, in which case each'll be more durable than the last,
> against more newly recognized or imagined kinds of hazards. And
> of course each one will cost more.

all true 8)

and the second and following telescopes als have the advantage of having 
much of the necessary constrcution equipment already on the moon .. the 
construction machinery can trundle from one site to the next on the 
ground, so that alone will reduce costs by a good margin

> It's relatively cold in North Texas today and I was wearing my
> old US Army field jacket.  I'm smug that, unlike Miles in his
> Dendarii Grays, I can get the zipper-and-snaps all closed up on
> MY old gear. Though I suspect that miles, returning from his
> honeymoon and recovery from Ceta death-drugs at the end of _DI_,
> all the extra weight he displayed in _ACC_ will have dropped
> away.
> Rush and Reed. I swear I didn't look it up. Old memories are on
> file but the indexing system is horribly damaged...  One loses
> more than weight as one ages.
> Yes, cat videos.  I imagine images of cats cavorting in low Lunar
> gravity will be QUITE amusing to viewers on Earth.

or in zero-g .. (i have a design for a zero-g cat litter box, that i am 
pretty optimistic about .. i cant wait for the competition to build one ..)

> And they'll
> need cats on purpose to deal with the rats (or feral canaries)

now that sounds interesting .. feral canaries in Luna City .. what will 
they eat?

> that they'll have by accident. I am not as sure of the canaries
> as I am the cat videos. But because much of Lunar construction
> will be underground -- mined -- I wouldn't be surprised.
> They'll live in CAVES.  And they'll LIKE it.

lava tubes




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