Currently this is rescheduled for 20:45 tonight. Launch window closed at
Could be well worth a look.
The success of the "Wonder Bra" for under-endowed women has encouraged the designers to come out with a bra for over-endowed women.
It's called the "Sheep Dog Bra"- it rounds them up and points them in the right direction.
Impressive to have it all work OK first time and simultaneous landings.
Not as potent in sheer power and lift terms as the good old Saturn V but
with the three boosters properly reusable a real step forwards.
Long way to go to collect your free used Tesla car though.
"Don't Panic" screen was a nice touch as was "Life on Mars"...
You have to admire Elon Musk for his vision and making it happen.
Actually (and you may know this already) it's the whole point of the
exercise. In order to get to Mars in a reasonable time and land a decent
payload, it's necessary to re-ignite a rocket engine facing into a
trans-sonic flow and land under thrust. That's what they're learning how
Today is Pungenday, the 38th day of Chaos in the YOLD 3184
Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn.
On Thu, 08 Feb 2018 08:06:43 +0000, Martin Brown wrote:
I'd have thought focussing your eyes to infinity would be easy seeing as
how it's the result of relaxing the eye's focussing muscles used to
accommodate for close in vision. Indeed, deep thought about a problem
gives you that "Far Away Look", hence the word "consider" which literally
translates as "to be with the stars".
That's almost twice as bright as Earth's albedo (39% back in 1976 when
Vangelis released his space physics inspired concept album, "Albedo
0.39). Since Venus is closer to the sun, its brightness will be even
higher than that simple albedo comparison suggests.
The problem is that to see a faint white speck against a bright blue sky
background you have to have an exact focus. Try it and see. It is also
quite easy to lose the thing even after you find it the first time.
Looking at a nearby con trail and transferring your gaze to the right
spot often works. Seeing a dot is much harder than you might think.
Not quite correct. With nothing specific to focus on, the eye tends to
settle at a couple of metres. All pilots are taught that lookout
requires an active action of focussing on the horizon (and then breaking
the scan into a series of segments where the eye is stationary,
interspersed with re-focussing on the horizon). In the dark there's also
the problem of the blind spot.
Many aero-med books discuss these but there are good articles here:
On Thu, 08 Feb 2018 15:20:31 +0000, nothanks wrote:
All very interesting. I guess the real problem with 'focussing' on far
away point sources of light is more to do with convergence than with
focussing per se. In dim night sky viewing, you need the use of both eyes
to mitigate the dark blind spot problem making use of both eyes correctly
converged an important requirement.
Eye convergence on distant objects can't be guaranteed by relaxation
alone, usually requiring some active trimming by muscular control.
Generally, in a sort of learned "Pavlonian" styled response, the lens
focussing muscle response takes its cue from the amount of convergence we
consciously 'dial in'.
I know from my experience with atropine drops that, my eyes lose all
accommodation powers leaving them relaxed into a state of focus at
infinity so I'm pretty sure that that bit about the eyes being in an
individually relaxed state when looking into the far distance is correct
and the corresponding convergence whilst not trimmed to precisely fixate
on a particular far and distant object when in deep thought, is
sufficient to give the outside observer, of another in deep thought, the
impression of "gazing at the stars" or the far away horizon.
However, when it comes to observing the "Morning" or "Evening" star,
namely Venus, that generally doesn't present any great difficulty with
naked eye observation since it is both very bright and discernible as a
tiny crescent, unlike the dimensionless points of light we call stars.
I have to admit that 'focussing on distance objects' relies not so much
on relaxed focussing muscles so much as on correct convergence which
almost always is a matter of some active muscle control and less about
total relaxation which usually only approximates the precise convergence
required for viewing distant objects. As you pointed out, my throw away
observation wasn't quite correct, merely just a small part of the whole
Well, the correct name for the effect is "empty field myopia", which
implies it is down to focus or, possibly, cognition. Muscles can only
contract and when relaxed the ciliary muscle pulls the lens to its
thinnest (longest focal length) condition ... so I can only surmise that
either the ciliary muscle isn't fully relaxed in this state or there's
summat else goin' on.
I looked around for an explanation and stumbled over this google book,
it doesn't have the answer but is a great thing to scan through:
For the avoidance of doubt I was talking about seeing Venus with the
naked eye at or around midday in a clear blue sky with the sun well
above the horizon. You need a good clear day and to stand in shadow.
The eye's default focus is as someone else has said is a few metres away
from you if you have normal vision. You have to make an effort to bring
the distant horizon into sharp focus assuming normal vision.
If you want a serious test of visual acuity try splitting the star
epsilon-Lyra naked eye soon after dark it is a 3' arc double star -
actually a double double in a small telescope it looks like:
with much bigger gap between then.
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