[rollei_list] Re: Tell the tales of Triotars
- From: Marc James Small <marcsmall@xxxxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Mon, 06 May 2013 23:26:32 -0400
At 08:08 PM 5/6/2013, Don Williams wrote:
One thing that has always confused me is that
the company that makes Questar telescopes used
to, perhaps still does, claim their systems beat
the theoretical resolution for their apertures.
The Questar Corporation claims that their
telescopes beat the hypothetical limiting
resolution for telescopes, quantified in the
nineteenth century by Lord Rayleigh
(mathematically derived) and by Dawes (derived
through observation). Both of these turn out to
be somewhat conservative, an open secret within
the astronomical and optical communities by the
first years of the last century. Braymer simply
exploited this reality and, yes, a Questar will
beat Dawes' Limit. In the late 1980's, the
Optical and Equipment Section of the British
Astronomical Association gathered a large number
of observations and confirmed the unreliability
of Dawes' Limit but, to date, no one has produced
a generally accepted replacement. Dawes set it
out as 1 arc second of resolution per 4.56 inches
of aperture. From my own experience with a
variety of telescopes, I would suggest 1 arc
second per 3.5 inches of aperture. My '62 Quartz
Standard Questar can reach that on a night with steady seeing.
Marc
msmall@xxxxxxxxxxxx
Cha robh bàs fir gun ghràs fir!
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