Re: Laser ranging to moon begs questions

On Tue, 30 Oct 2007 14:30:28 -0700, Martin Brown
<|||newspam|||@nezumi.demon.co.uk> wrote:

On Oct 30, 7:19 pm, John C. Polasek <jpola...@xxxxxxxxxx> wrote:
On 30 Oct 2007 13:15:27 -0400, Craig Markwardt

Furthermore, since returned photons are grouped/averaged into "normal
points" of duration ~10-15 minutes (wall clock time) before delivery
to archives for science analysis, the number of photons per unit wall
clock time is relevant. While this discussion has focussed on the
McDonald Observatory, which typically receives ~10 returned phtons per
normal point, the OCA observatory typically receives ~100 photons per
point, and Apache Point many thousands (Shelus et al., Murphy et al.).
[snip]
That is a weak reply for several reasons. (a) More than one reference
was cited; (b) the originally mentioned Shelus paper is freely
available; (c) many municipal public libraries hold scientific
journals; (d) *Science* magazine articles are available for very
modest fee.

I have found that when I become really interested in a paper,
that as member of the unwashed, I have to pay $30 for the paper. The
.pdf cited below for example is not worth $30. (I don't see a source
mentioned-isn't it copyrighted? How would I look it up?)

Go to the local university or public library and talk nicely to a
librarian.
Google is your friend ADS abstracts gives for example on Apache point:

http://adsabs.harvard.edu/abs/2006AAS...20915402B

They have no reason to lie about the capabilities of the instrument.
If you look carefully you may find a few articles that are free access
- not all the journals are pay per view for public access. Or their
own site:

http://www-physics.ucsd.edu/~tmurphy/apollo/apollo.html

For a basic accessible answer.

You have far overestimated my interest in the details of this process.
I simply asked a simple question, expecting a simple answer to how you
can determine fractional cm/s with a few pulses per minute and find
myself drawn into a 70 message harangue.
It is beginning to appear that you are not capable of answering a
simple question.

Not every simple question has a simple answer. There is enough signal
to noise available on the top flight instruments now to measure the
distance from telescope to moon with astonishing precision.

Regards,
Martin Brown
Thank you.
John Polasek
.

Relevant Pages

  • Re: Laser ranging to moon begs questions
    ... points" of duration ~10-15 minutes (wall clock time) before delivery ... to archives for science analysis, the number of photons per unit wall ... clock time is relevant. ...
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  • Re: CPU time versus wall clock time
    ... >> What is CPU time, and how does it relate to wall clock time. ... differ. ...
    (alt.comp.lang.learn.c-cpp)