Sky & Telescope - March 2019 - 6

FROM OUR READERS

Animated Almanac
I've built a device I call the SkyClock that animates S&T's Skygazer's Almanac by
pointing to sky events identiﬁed on the Almanac in real time.
The Almanac is mounted on a vertical cylinder that rotates once a day, driven
by a stepper motor. A vertical screw connected to the cylinder with friction plates
moves a pointer downward one day on the date scale per revolution of the cylinder.
Thus, in one year the pointer moves down the Almanac from top to bottom.
It uses an inexpensive 5-volt stepper motor driven by a circuit board programmed with appropriate time delays between steps. The link between the
rotating cylinder and the screw that moves the pointer downward consists of two
spring-loaded plywood disks that supply a constant contact pressure. The ratio of
their diameters provides the required rotation rate of the screw.
The SkyClock isn't intended to generate new information not already on the
Almanac, but it's a real-time clock that's fun to watch and gives a visual sense of
time and the events unfolding in the sky. The device gives a particularly interesting
visual representation of the rising and setting times of the Sun and how the day
and night times change throughout the year.
There is, of course, an inherent irony in this project: It takes a sophisticated
computer-generated map based on physics and complex astronomical calculations
and turns the information back into an 18th-century analog device!
Bernd Enders * San Rafael, California
t Bernd Enders's SkyClock updates the display on the Skygazer's Almanac on a daily basis.

It was with great sadness that I read
of Sue French's retirement from her
Deep-Sky Wonders column (S&T: Dec.
2018, p. 4). As someone who also writes
- in my case a far more modest little
astronomy column in the local newspaper - it's easy to feel a strange sense
of not knowing if anyone is actually
reading it. It's not a "live performance"
where the audience claps at the end.
As this curtain closes let me assure
you, Sue, of the applause from all of us.
Your writing has inspired wonder, and
your sense of joy has been spread far
and wide. For me, and probably most,
the guides you have provided are read
and then re-read again and again as
each view of the sky moves into place.
You may not be writing any more columns, but Deep-Sky Wonders will live
on as a timeless resource for observing
the universe around us.
William Maxwell
Camano Island, Washington

I have just sat down to read this month's
magazine, and I must say that the Spec6

M A RCH 2 019 * SK Y & TELESCOPE

trum editorial was moving. Sue French's
columns back in the early 2000s were
very important to me as I re-entered the
world of astronomical observing after a
hiatus of 30-plus years.
Amateur astronomy had changed
so much from the late 1960s and early
'70s. Living in northern New Jersey, I
had almost despaired of what I could
do with the small equipment I could
afford. Sue's columns saved the day
for me. She was the perfect instructor,
always knowledgeable and encouraging.
Her writing style encouraged me with a
"you can do this" style of enthusiasm.
It was an enthusiasm that also carried
over in her public speaking, as when I
heard her talks at NEAF.
I enjoyed her monthly columns
and the published collections as well.
It was her works that made me feel
comfortable once again in this hobby.
So, thanks so much, Sue. It has been a
pleasure reading your columns. Enjoy
your retirement, and may it be ﬁlled
with clear skies.
Dale Patterson
Washington, New Jersey

Home Sweet Hole
Michael Poll's letter (S&T: Dec. 2018,
p. 6) describes Tswaing Meteor Crater in
South Africa, which "must be one of the
more easily accessed impact craters!" In
Quebec, I actually live in one.
About 30,000 people live in the Charlevoix crater, in some 11 small towns
and villages. The crater is referenced in
the RASC's Observer's Handbook 2019
on page 261. It's a 54-km semicircular
crater, the missing half being buried
under the St. Lawrence River and the
Appalachian tectonic plate.
Hugues Lacombe
Baie-Saint-Paul, Quebec

An Amazing Revelation
NGC 1514 in Taurus is sometimes
called the "Crystal Ball Nebula," but I
think the name "Herschel's Revelation"
is far more signiﬁcant. This is the object
that convinced Sir William that nebulae
are real and not, as was the belief then,
just masses of unresolved stars. His profound insight came at seeing the clear
separation of the surrounding nebula
from the obvious central star. It was yet

BERND ENDERS

A Deep-Sky Goodbye

Sky & Telescope - March 2019

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