Sky & Telescope - November 2019 - 7

start with, which would reduce sensitivity. (Normal is about 98% for most
people.) I don't know if the effect of
oxygen on me would be as great if I were
at sea level, although other observatory staff members did report the same
effect. There's probably a lot of individual variation.
Tom Sargent
Tucson, Arizona

Legacy Observatories
I was very happy recently to get a call
from Sam Hale, CEO of Mount Wilson Institute. Sam is the grandson
of George Ellery Hale (1868-1938),
founder of Kenwood, Yerkes, and Mount
Wilson Observatories, and a key ﬁgure
in the creation of Palomar Observatory.
Sam asked me to join a small and informal weekend meeting bringing together
people concerned with "legacy observatories." The proposal was to consider a
new organization that would serve the
needs of such institutions.

The meeting took advantage of initial
considerations written down by a small
group of senior astronomers who had
gathered informally at a prior meeting
of the American Astronomical Society
(AAS). As resolved that weekend, the
working name for the new organization
is Alliance of Historic Observatories.
Three participants agreed to lead an
effort to reﬁne a draft mission statement and other key wording, and the
group plans to reconvene this fall at an
event hosted by Palomar Observatory.
Of many extremely interesting
points raised, it's notable that the
intangible spirit of astronomical observatories, and of their grand historic
instruments, was not overlooked. The
group recognized the power of this for
education.
All of us interested in preserving
astronomical heritage and exploiting

1969

1994

John W. Briggs
President, Antique Telescope Society
Magdalena, New Mexico

FOR THE RECORD

* In "The Moon Three Ways" (S&T: July
2019, p. 22), the Moon in the composite
photograph that opens the article is waxing, not waning.
* Several alert readers reminded us that
Earth's distance from the Sun at aphelion
(S&T: July 2019, p. 47) is 1.0168 astronomical units, not 1.1068 a.u. Nostra culpa.

* In "Action at Jupiter" (S&T: Aug. 2019,
p. 50), the second sentence should read in
part ". . . and diminishes to a still-luminous
-2.2 by the end of the month."

SUBMISSIONS: Write to Sky & Telescope, 90 Sherman St., Cambridge, MA 02140-3264, U.S.A. or email: letters@
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75, 50 & 25 YEARS AGO by Roger W. Sinnott
1944

it for education and engagement can
be pleased that development of the
Alliance of Historic Observatories will
certainly continue.

º November 1944
Faraway Suns "Dr. C. K. Seyfert
and Prof. J. J. Nassau, of the Warner and Swasey Observatory, find
that there are around 2,500 supergiant stars in the Andromeda system [Messier 31], each of which is
at least 1,000 times as bright as our
sun. The investigation was made
on photographs obtained with the
new 24-inch Schmidt telescope at
Cleveland. We thus actually have
a far more complete census of the
supergiants in this distant system
than in our own galaxy."
Because we see the Milky Way
edge on, many of its more distant
stars are obscured from our view
by interstellar dust.
º November 1969
Meteor Up Close "The unusual
experience of seeing a 1st-magnitude meteor pass through the
field of view of a 30-inch refractor at 600× is described by W. A.
Feibelman. [He] was photographing

the planetary nebula NGC 7009 on
September 2, 1968, with the Thaw
refractor at Allegheny Observatory
in Pittsburgh. The guiding eyepiece
into which he was looking received
part of the beam of the 30-inch
f/18.5 objective, and had a field of
one minute of arc.
"The very swift passage of the
meteor left a yellow trail about
seven to 10 seconds of arc in
width. After the observer recovered from the momentary dazzle,
he saw the field filled with tiny
luminous centers moving with the
same velocity and direction as the
meteor, except along the original
trail, which was now empty. Quickly
this smooth motion changed to a
turbulent one, with twisting filaments and eddies, until the whole
phenomenon faded from view. The
entire sequence of events lasted
only about four seconds."
º November 1994
Brand New Neighbor "An international team of astronomers has
found a large spiral galaxy in our

cosmic backyard. The object,
located in Cassiopeia . . . was
announced at the 22nd General
Assembly of the International
Astronomical Union. . . .
"Dubbed Dwingeloo 1, the
galaxy was detected with the
25-meter radio telescope in
Dwingeloo, the Netherlands, one
of the oldest radio telescopes in
the world. Renée Kraan-Korteweg
. . . and Andrew J. Loan [and colleagues] found the galaxy [during]
a search for hitherto unknown
galaxies in the Zone of Avoidance,
the part of the sky that is largely
hidden from view by dust in the
plane of our galaxy. . . . According
to team member W. Butler Burton
(Leiden Observatory), it is probably
10 million light-years away [or] just
outside the Local Group."
In 1996, Loan and his team
identiﬁed Dwingeloo 1 as a dim
and extended glow of total visual
magnitude 14 using the 2.5-meter
Isaac Newton Telescope (Canary
Islands), among others. It turns out
to be a barred-spiral galaxy.

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Sky & Telescope - November 2019

Table of Contents for the Digital Edition of Sky & Telescope - November 2019