Sky & Telescope - July 2020 - 7

The diffraction
grating wasn't
quite parallel with
the needle, so the
resolution was poor.
Nevertheless, this
experiment is well
worth trying again.
A needle spectrum

Kevin J. Kilburn
Manchester, England

The Little Scope That Could
I bought my nephew a telescope many
years ago. He quickly lost interest, and
it sat in a basement for more than two
decades under extreme temperature and
humidity conditions. A few years ago, I
decided to resurrect it, clean it up, buy
some hardware for it, and take a look at
the night sky. To my surprise, I saw the
rings of Saturn and was ecstatic. Then, I
purchased some additional hardware to
record what I was observing. The image
wasn't as dramatic as the ﬁrst scope
I peered through (my industrial arts

teacher's Questar back in the early '60s,
when I was in eighth grade), but it was
still very cool! The real wonder is seeing
the Sun's reﬂected light from Saturn
having taken 71 minutes to reach Earth
through 60 mm of ground glass.
Ed Huff
Tucson, Arizona

S&T Appreciates You
I have been subscribed to S&T for more
than 40 years with only a few interruptions on my end since an initial gift
from my parents while in middle school.
This most recent renewal involved a bit
of hesitation on my end. Why bother
renewing a subscription when I may not
have the time to read my monthly magazine? Should I continue experiencing the
guilt in having an issue or two neglected
in their plastic sleeve for a month or
longer after arrival?

1970

K E V IN K IL B U R N

1995

R. S. Marvin
Farmington Hills, Michigan

FOR THE RECORD

* In the graph of the Orientale basin (S&T:
Apr. 2020, p. 53) the average elevation
is in meters not kilometers. The correct
graph can be seen on our new website
https://is.gd/Errata2020.

SUBMISSIONS: Write to Sky & Telescope, One Alewife Center, Cambridge, MA 02140, USA or email: letters@
skyandtelescope.org. Please limit your comments to 250 words; letters may be edited for brevity and clarity.

75, 50 & 25 YEARS AGO by Roger W. Sinnott
1945

I renewed my subscription to thank
the S&T editors, employees, and contributors of this iconic publication.
Their efforts and enthusiasm continue
to spark the interest in observational
astronomy of not only those whose
ﬁ rst exposure was a gift issue of S&T
but also to keep alive the interest of
long-time subscribers. I hope that S&T
continues to serve as much of a magnet
to talented contributors, as it does to
keep its subscribers committed to the
magazine's success.

º July 1945
Corona Revealed "By far the most
striking results obtained by French
astronomers during the war are
those by Bernard Lyot and his
collaborators on the Pic du Midi.
The coronagraph has an aperture
of about eight inches and a focal
length of over 13 feet, and is used
with a . . . monochromatic filter . . .
"Films covering a total duration
of 92 hours fail to confirm actual
motions in the corona reported
by some observers [during total
eclipses] - no moving streamers are observed. The corona as a
whole seems to pulsate, however,
getting brighter and fainter over
large segments. [Before] Lyot built
his coronagraph we had to wait for
an eclipse of all of the sun before we
could even hope to see the corona."
º July 1970
Microbe on the Moon "[A] microorganism accidentally carried
to the moon three years ago in

Surveyor 3's camera has been
recovered from inside the camera
that was brought back to Earth by
the Apollo 12 crew in November,
1969. The microorganism has
been identified as Streptococcus
mitis, a harmless species often
found in the human respiratory
tract. Apparently it survived the
Surveyor launch, the three-day
journey under vacuum conditions
to the moon, and 950 days in the
hostile lunar environment.
"Captain [Frederick] Mitchell
and his team spent five months
in studying Surveyor 3 camera
parts retrieved from the moon.
The microorganism was found in
a small bit of polyurethane foam
which was used as insulation in
circuit boards inside the camera
housing. [Air Force microbiologists]
placed the cubic millimeter of foam
in a bacterial culture medium (Thioglycollate broth) at 37° C.
"The first signs of life were
observed after four days of incubation . . . and on the next day 'the
tube was turbid with growth.'"

º July 1995
Origin of Comets "A team of four
astronomers led by Anita Cochran
(University of Texas) has exploited
the Hubble Space Telescope to
detect hints of a large population of
extremely faint objects orbiting the
Sun beyond Neptune.
"[They] combined 34 Hubble
images of a single field, 4 arcminutes on a side . . . They identified
and removed the field's stars and
galaxies, then combined the images
again with two kinds of relative
offsets. [Dozens] more objects were
found in . . . an excess far beyond
that expected by chance. . . .
"This statistical excess implies
that many thousands of objects
. . . await discovery in every
square degree of sky along the
ecliptic. . . . Their discovery thus
strengthens the belief that the
Kuiper Belt is the dominant source
of short-period comets."
Today's thinking shifts the bullpen of periodic comets to the scattered disk, a broader, less stable
region also just beyond Neptune.
s k y a n d t e l e s c o p e . o r g * J U LY 2 0 2 0

https://www.is.gd/Errata2020 http://www.skyandtelescope.org

Sky & Telescope - July 2020

Table of Contents for the Digital Edition of Sky & Telescope - July 2020