Sky & Telescope - December 2020 - 6

FROM OUR READERS

"

Diana Hannikainen replies: Indeed,

astronomers have detected radio
emission after events that have given rise
to gravitational waves, such as the neutron
star merger recorded in 2017. They don't
understand the origin of the radio emission completely, but one scenario proposes
that the merger event creates a narrow,
collimated, bipolar jet. As the jet plows
outward, it shocks the interstellar medium,
and scientists receive this as radio emission
- this behavior is akin to the radio jets from
quasars and microquasars.
S Members of Troop 12 proudly display their
new telescopes.

The students of Scout Troop 12 in our
town were determined not only to earn
their Astronomy merit badges but also
to build their own telescopes. Using
the plans described by Jerry Oltion in
"The STEM Spyglass Project" (S&T:
July 2020, p. 74), they deconstructed
binoculars, removed the eyepieces, and
transplanted them into optical tube
assemblies using a lot of tape. Then
they secured and glued the objective
lenses into place. They brought their
telescopes to our socially distanced
scout summer camp to ﬁ ne-tune their
instruments. Bad weather almost
ruined the possibility of using their

scopes, but at the last minute the skies
cleared. They got to see Jupiter and its
moons as well as Saturn.
The scouts earned their Astronomy
merit badges and formed lifelong
memories. The adult leaders became
enthusiastic partakers of the night sky
and created one of the best star parties
I've ever attended. Troop 12 expresses
its gratitude to the Wootens and to Sky
& Telescope's editors for sharing their
encouragement and expertise. We hope
that others will be inspired to make
their own telescopes in the near future.

A Horn for Every Home

Purcell to detect 21-cm radio waves from
neutral hydrogen. The spectrometer uses
GNU Radio, which is a free and opensource toolkit for software radio.
We would greatly appreciate any
feedback. Our ultimate goal is to have
"a horn in every backyard" that can be
linked as one big interferometer!

I enjoyed reading Diana Hannikainen's
article "The Radio Sky" (S&T: Aug.
2020, p. 12) and the overview of radio
astronomy that it provided. I'm an amateur radio astronomer, and I teach high
school physics. For the past four years,
I've been involved in the Digital Signal
Processing in Radio Astronomy program
developed by West Virginia University
and Green Bank Observatory.
A main focus of this program is to
help teachers build radio telescopes and
develop curriculum for their classrooms.
We developed a website wvurail.org/
dspira-lessons that provides instructions and lessons on building and
operating a horn radio telescope that
is similar in design to the one used by
Harold Irving Ewen and Edward Mills
6

DECEMBER 2 02 0 * SK Y & TELESCOPE

Thomas C. Rushton
Huntington, West Virginia

John Makous
Charlotte, North Carolina

Spacetime Disturbances
Your excellent article, "The Radio Sky,"
made me wonder if events that cause
gravitational waves also produce an
electromagnetic signal with a similar
frequency spectrum. It would arrive
after the gravitational wave.
Ward Halverson
Cambridge, Massachusetts

Inspirational Eclipses
Nicole Nazzaro's Focal Point (S&T:
Aug. 2020, p. 84) about the total lunar
eclipse on July 6, 1982, brought back
memories. I was 13 years old and living
in Michigan at the time. I too loved
science and was a misﬁt - except in
my backyard under the stars.
I loved astronomy in high school
and considered it as a career. In college,
I studied aerospace and mechanical
engineering, leaving astronomy behind.
Through the '90s, I built my career, got
married, and did other hobbies. Then I
also started a family and dusted off my
old gear. In hindsight, astronomy never
really left me. It was one of the main
inﬂuences that steered me toward my
technical vocation.
It is amazing how much a simple
hobby can inﬂuence a person's life. If
children enjoy a scientiﬁc activity, we
need to feed it. Even if they later lose
interest, the experience may spark
future achievements.
Michal Warzecha
El Dorado Hills, California

Just like Nicole Nazzaro, I was inﬂuenced
by an eclipse and a couple of science-ﬁction TV shows. But in my case, it was the
1970 eclipse of the Sun. I had a 60-mm
refractor with the solar ﬁlter that no one
uses anymore, and many people from
my neighborhood came over to watch
it. I found several deep-sky objects with
that little telescope. As I grew older, I
wanted to be an astronomer, but I soon
realized that I didn't have the math skills
for it. So I got married and joined the
Army. I've been in and out of astronomy

BERNARD VA LLEJOS

DIY Refractors
http://www.wvurail.org/dspira-lessons
Sky & Telescope - December 2020

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