[FoRK] Astronomy units question

Dave Long dl at silcom.com
Wed Apr 20 08:33:28 PDT 2005


> FYI, arc minutes are denoted '... So one could note a bearing of 40
> (degrees) 30'15" if the available instruments were accurate enough.

I ran across this description of how early
20th century experimental results depended
greatly on a subjective experimenter:

TN Whitehead, _The Design and Use of Instruments and Accurate Mechanism_
> In the case of normally good vision, the eye has the faculty of 
> resolving
> two points separated by not less than about 50" of angle, but it is 
> well
> known that skilled observers can set well designed symmetrical cuts 
> with
> a m.e. not exceeding 5" to 10" of angle at the eye ... if a skilled
> observer is shown a setting or "cut" already performed, and is asked to
> judge its truth without touching the control, he will probably judge it
> correct provided the error does not exceed about 50" at the eye; the 
> same
> observer will, however, fairly consistently perform the same cut with
> errors not exceeding 5" to 10".  The inference is that the mind 
> receives
> a number of sensations of different character, and then performs some
> mental act of synthesis, the outcome of which is an order to the
> controlling hand.
> ... a surprisingly high precision can be obtained for a set of perhaps
> 20 readings taken at a sitting.  If the observer is then interrupted,
> speaks to someone, or has lunch, etc., and repeats the set, he will
> obtain a similar precision; but the means of the two sets may well be
> separated by an interval at least five to ten times the m.e. of either
> set.  Similarly two observers performing the same operations may have
> the means of their sets so separated.

and now wonder if all of this attention on
the experimenter as a crucial last link in
an observation led to the consciousness/QM
mumbo-jumbo?

-Dave



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