Sky & Telescope - August 2022 - 7

ride the subway-surface trolley toward
downtown. I'd then buy a copy of Sky
& Telescope at the bookstore of the
Fels Planetarium and, sitting by the
fountain, indulge my celestial fantasies,
which were first created by Roy
K. Marshall of Fels and his very early
television shows under that hallowed
dome, Percival Lowell's books, and the
wonderful art of Wally Wood in E. C.
Comics' Weird Science and Weird Fantasy.
I still have, in mint condition, the
comics and books, as well as my first
scope: a 2.4-inch (60-mm) Unitron
Model 114 refractor!
William Bonney
Moscow, Idaho
Sketching Markarian's Chain
I enjoyed Howard Banich's " Markarian's
Marvelous Chain " (S&T: Apr.
2022, p. 22). It brought back strong
memories of the night of April 5, 2008,
when I viewed and sketched Markarian's
Chain in my 10-inch Dobsonian
the importance of taking notes and the
joy of reliving moments through them.
Even at a conservative 100 billion
stars per galaxy, the idea of pondering
the combined light of over a trillion
stars at once staggers me.
Steve Riegel
Colorado Springs, Colorado
 Steve Riegel drew this sketch of Markarian's
Chain in his logbook in 2008. North is down.
with a 24-mm Hyperion eyepiece from
Figueroa Mountain in California. That
logbook entry ranks in the top five for
me out of the 15 years or so that I've
been observing. I often use it as an
example in my high school classes on
FOR THE RECORD
* In " Nearest Supermassive Black Hole
Pair Discovered " (S&T: Apr. 2022, p. 10),
François Schweizer and team identified the
galaxy's double nucleus, and showed that
one of them hosts an active supermassive
black hole, in 2018. Karina Voggel and
colleagues significantly improved the mass
measurements for both black holes in 2022.
* On page 56 of the April issue, an astrophotographer
reduces the effective noise
by half each time they multiply the number
of images by four.
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75, 50 & 25 YEARS AGO by Roger W. Sinnott
1947
1972
º August 1947
Eclipses or Not? " In Coma Berenices,
the star known as Alpha or
42 is a visual binary with a period
of 25.87 years. Its component
stars are practically identical,
of magnitude 5.2 and spectral
class F5. . . . Dr. Luigi Jacchia,
of Harvard College Observatory,
finds this star to offer the interesting
possibility of the eclipse of one
component by the other . . .
" [At] their distance of about 50
1997
light-years, these stars, if each is
about the same size as the sun,
should have apparent diameters of
0.0006 seconds, which makes the
chances of eclipse seem not too
favorable. . . . But in 1963, about
April, [they will have roughly the
same] minimum separation. "
Despite the system's accurately
known orbit, tipped almost exactly
edge on to our view, astronomers
failed to detect an eclipse in
1963 and again in 2015. The next
chance is in 2040.
º August 1972
Wandering Phobos " At the Royal
Greenwich Observatory, A. T. Sinclair
has completed a comprehensive
study of the orbital motions
of the two natural satellites of
Mars . . . One purpose of the new
investigation . . . was to clarify the
question of the secular acceleration
of the satellite motions.
" This effect was first pointed
out in 1945 by B. P. Sharpless at
the U.S. Naval Observatory, who
found that Phobos appeared to be
gradually speeding up, at a rate that
would put it 19 degrees ahead in its
orbit by the end of a century. . . .
" Dr. Sinclair used a total of
3,107 observations of the two
satellites . . . This analysis showed
that the supposed speeding up of
Phobos resulted from the observations
made at the oppositions of
1877, 1879, and 1881. When these
observations are omitted [the
anomaly goes away]. "
Sinclair's study closed the book
on a wild suggestion by Russian
astronomer I. S. Shklovskii. In
1959, he had noted that Phobos's
odd motion could be accounted
for if it were hollow (that is, something
built by aliens).
º August 1997
Galaxy Survey " In five short years,
a state-of-the-art telescope will
measure the distances to one million
galaxies. . . .
" It was with this dream in mind
that the Sloan Digital Sky Survey
(SDSS) was born. Nearly ready to
begin its five-year journey through
space and time, [the 2.5-meter
reflector at Apache Point Observatory
in New Mexico] will produce
detailed color images of about a
quarter of the sky [and lead to]
a three-dimensional map of the
universe's structure throughout a
volume a thousand times larger than
that probed by existing surveys. "
Participant Gillian Knapp limited
her article to initial expectations
for the SDSS. With ever-evolving
instrumentation and techniques, the
survey goes on. Last year its scientific
team issued Data Release 17.
sk yand tele scope .o r g * AUGUST 2022
7

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Sky & Telescope - August 2022

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