Sky & Telescope - April 2021 - 6

FROM OUR READERS

Being a bino nut myself, I enjoy reading Matt Wedel's Binocular Highlight
column. I also enjoy the observing
articles he writes. So I plowed into
" The Caldwell Catalog Turns 25 "
(S&T: Dec. 2020, p. 20) with interest -
most enjoyable! I've ignored the catalog
since it came out, but after reading his
article, I may give it a try!
I had the pleasure of meeting
Patrick Moore in 1986 on a two-week
tour in Australia to see Halley's Comet.
The people on
the trip were split
between three
buses, and each
had a different
tour leader. I
lucked out - PatS Patrick Moore and
rick Moore was
Bill Dellinges pose
our guide! I knew
for a picture during
of his fame, so I
a two-week tour in
was delighted.
Australia in 1986.

Bill Dellinges
Apache Junction, Arizona

Although Matt Wedel averred that
the goal of his article was " not to
focus on his [Patrick Moore's] political opinions, " he nevertheless chose to
mention them and made it clear that
he disagreed with Moore's views.
Some other aspects of Patrick
Moore's life that may not be well
known to fans of his astronomical
contributions are that he was a keen
follower of cricket, a more than competent performer on the xylophone,
and a staunch and vocal opponent of
fox hunting.
Jeremy Tatum
Victoria, British Columbia

Sketching OB Associations

Cruising Under Totality

I enjoyed reading Matt Wedel's " The
Fires of Youth " (S&T: Jan. 2021, p. 43).
Years ago, I visually sketched my way
through a number of OB associations listed in the article " In Pursuit
of OB Associations " by Joseph Caruso
(S&T: Jan. 1986, p. 110).
I have more sketches of OB associations and star charts on my website:
stellar-journeys.org/OB-Tour.htm.
One of the reasons that I really enjoy
reading S&T is the wonderful observing
articles covering a wide range of objects
suitable for small and large telescopes.
Barely an issue goes by where I'm not
cutting out and saving something for a
future observing project!

Rick Fienberg's " Corona Virus "
(S&T: Jan. 2021, p. 84) brought back
fond memories of two special cruises.
Having never seen a total solar eclipse
before, my wife and I planned to observe
the July 11, 1991, one in Hawai'i. We
luckily found ourselves off the shores of
Mazatlán, Mexico, on Carnival Cruise
Line's Jubilee to watch the event. Buzz
Aldrin was a guest lecturer! It was a
fantastic cruise experience.
Then, during the February 26, 1998,
eclipse, we were on Carnival's new,
larger Fascination near Aruba. Although
totality was shorter on this cruise, it
had two brilliant " diamond rings " !
Each cruise also had a great captain.
And both cruises were full of friendly
people and pure enthusiasm - the
cheering as darkness fell!

Larry McHenry
Pittsburgh, Pennsylvania
W Larry McHenry
observed Orion OB-1a
on January 29, 1993,
through an 80-mm
(3-inch) refractor with
a 32-mm (1.25-inch)
eyepiece and drew this
sketch of what he saw.

6

What a walking encyclopedia! The
guy could (and did) lecture on any
astronomical subject off the top of his
head. I was in heaven.

APRIL 2 021 * SK Y & TELESCOPE

John Kuczek
Vero Beach, Florida

The Formation of Planets
The impression that I got from Edwin
Bergin's article " Follow the Carbon "

(S&T: Dec. 2020, p. 34) is that the
amount of carbon an Earth-like planet
in the habitable zone of a star system
winds up with is highly dependent on
the circumstances and history of that
star system. It could range from almost
no carbon to a significantly greater
percentage of carbon than Earth has. As
we continue to investigate, we should
expect the unexpected.
James Scott
Vernon, New Jersey

Einstein Rings
Thank you for Monica Young's News
Note " 'Dead Ringer' for the Milky
Way Found in the Early Universe "
(S&T: Dec. 2020, p. 10). It takes a
remarkable alignment of the foreground and background galaxies to
produce such a symmetrical ring.
Your article triggered a thought
that I should have had years ago, when
Einstein rings were first observed:
Where is the foreground galaxy? I can
roughly understand the physics of the
ring formation, but what happens to the
foreground galaxy's light?
It seems that it should be visible
somewhere, maybe in the center of the
one shown and off-center in less symmetrical rings or arcs.
Phil Petersen
League City, Texas

"

Monica Young replies: That's a

really good question! In this case,
the foreground galaxy is invisible because
it doesn't emit much light at the specific
wavelength the scientists are looking at.
Francesca Rizzo and colleagues used the
Atacama Large Millimeter/submillimeter
Array (ALMA) to look at emission from ionized carbon in the background galaxy. This
spectral line is emitted at 158 microns, but
the background galaxy is so far away (redshift 4.2), that the wavelength stretches to
826 microns (0.8 millimeter) by the time
it passes through the expanding universe
to reach Earth. The foreground galaxy, at
redshift 0.2, doesn't emit much light at
this wavelength, so it's not visible in the
ALMA image.
However, in other images of lensed galaxies, such as those taken by the Hubble

DELLING ES A ND M OORE: BILL DELLING ES

Patrick Moore's Caldwell Catalog


http://stellar-journeys.org/OB-Tour.htm

Sky & Telescope - April 2021

Table of Contents for the Digital Edition of Sky & Telescope - April 2021

Contents
Sky & Telescope - April 2021 - Cover1
Sky & Telescope - April 2021 - Cover2
Sky & Telescope - April 2021 - 1
Sky & Telescope - April 2021 - Contents
Sky & Telescope - April 2021 - 3
Sky & Telescope - April 2021 - 4
Sky & Telescope - April 2021 - 5
Sky & Telescope - April 2021 - 6
Sky & Telescope - April 2021 - 7
Sky & Telescope - April 2021 - 8
Sky & Telescope - April 2021 - 9
Sky & Telescope - April 2021 - 10
Sky & Telescope - April 2021 - 11
Sky & Telescope - April 2021 - 12
Sky & Telescope - April 2021 - 13
Sky & Telescope - April 2021 - 14
Sky & Telescope - April 2021 - 15
Sky & Telescope - April 2021 - 16
Sky & Telescope - April 2021 - 17
Sky & Telescope - April 2021 - 18
Sky & Telescope - April 2021 - 19
Sky & Telescope - April 2021 - 20
Sky & Telescope - April 2021 - 21
Sky & Telescope - April 2021 - 22
Sky & Telescope - April 2021 - 23
Sky & Telescope - April 2021 - 24
Sky & Telescope - April 2021 - 25
Sky & Telescope - April 2021 - 26
Sky & Telescope - April 2021 - 27
Sky & Telescope - April 2021 - 28
Sky & Telescope - April 2021 - 29
Sky & Telescope - April 2021 - 30
Sky & Telescope - April 2021 - 31
Sky & Telescope - April 2021 - 32
Sky & Telescope - April 2021 - 33
Sky & Telescope - April 2021 - 34
Sky & Telescope - April 2021 - 35
Sky & Telescope - April 2021 - 36
Sky & Telescope - April 2021 - 37
Sky & Telescope - April 2021 - 38
Sky & Telescope - April 2021 - 39
Sky & Telescope - April 2021 - 40
Sky & Telescope - April 2021 - 41
Sky & Telescope - April 2021 - 42
Sky & Telescope - April 2021 - 43
Sky & Telescope - April 2021 - 44
Sky & Telescope - April 2021 - 45
Sky & Telescope - April 2021 - 46
Sky & Telescope - April 2021 - 47
Sky & Telescope - April 2021 - 48
Sky & Telescope - April 2021 - 49
Sky & Telescope - April 2021 - 50
Sky & Telescope - April 2021 - 51
Sky & Telescope - April 2021 - 52
Sky & Telescope - April 2021 - 53
Sky & Telescope - April 2021 - 54
Sky & Telescope - April 2021 - 55
Sky & Telescope - April 2021 - 56
Sky & Telescope - April 2021 - 57
Sky & Telescope - April 2021 - 58
Sky & Telescope - April 2021 - 59
Sky & Telescope - April 2021 - 60
Sky & Telescope - April 2021 - 61
Sky & Telescope - April 2021 - 62
Sky & Telescope - April 2021 - 63
Sky & Telescope - April 2021 - 64
Sky & Telescope - April 2021 - 65
Sky & Telescope - April 2021 - 66
Sky & Telescope - April 2021 - 67
Sky & Telescope - April 2021 - 68
Sky & Telescope - April 2021 - 69
Sky & Telescope - April 2021 - 70
Sky & Telescope - April 2021 - 71
Sky & Telescope - April 2021 - 72
Sky & Telescope - April 2021 - 73
Sky & Telescope - April 2021 - 74
Sky & Telescope - April 2021 - 75
Sky & Telescope - April 2021 - 76
Sky & Telescope - April 2021 - 77
Sky & Telescope - April 2021 - 78
Sky & Telescope - April 2021 - 79
Sky & Telescope - April 2021 - 80
Sky & Telescope - April 2021 - 81
Sky & Telescope - April 2021 - 82
Sky & Telescope - April 2021 - 83
Sky & Telescope - April 2021 - 84
Sky & Telescope - April 2021 - Cover3
Sky & Telescope - April 2021 - Cover4
https://www.nxtbook.com/nxtbooks/aas/st_202412
https://www.nxtbook.com/nxtbooks/aas/st_202411
https://www.nxtbook.com/nxtbooks/aas/st_202410
https://www.nxtbook.com/nxtbooks/aas/st_202409
https://www.nxtbook.com/nxtbooks/aas/st_202408
https://www.nxtbook.com/nxtbooks/aas/st_202407
https://www.nxtbook.com/nxtbooks/aas/st_202406
https://www.nxtbook.com/nxtbooks/aas/st_202405
https://www.nxtbook.com/nxtbooks/aas/st_202404_qr
https://www.nxtbook.com/nxtbooks/aas/st_202404
https://www.nxtbook.com/nxtbooks/aas/st_202403
https://www.nxtbook.com/nxtbooks/aas/st_202402
https://www.nxtbook.com/nxtbooks/aas/st_202401_aus
https://www.nxtbook.com/nxtbooks/aas/st_202401
https://www.nxtbook.com/nxtbooks/aas/st_202312_aus
https://www.nxtbook.com/nxtbooks/aas/st_202312
https://www.nxtbook.com/nxtbooks/aas/st_202311
https://www.nxtbook.com/nxtbooks/aas/st_202310
https://www.nxtbook.com/nxtbooks/aas/st_202309
https://www.nxtbook.com/nxtbooks/aas/st_202308
https://www.nxtbook.com/nxtbooks/aas/st_202307
https://www.nxtbook.com/nxtbooks/aas/st_202306
https://www.nxtbook.com/nxtbooks/aas/st_202305
https://www.nxtbook.com/nxtbooks/aas/st_202304
https://www.nxtbook.com/nxtbooks/aas/st_202304_qr
https://www.nxtbook.com/nxtbooks/aas/st_202303
https://www.nxtbook.com/nxtbooks/aas/st_202302
https://www.nxtbook.com/nxtbooks/aas/st_202301
https://www.nxtbook.com/nxtbooks/aas/st_202212
https://www.nxtbook.com/nxtbooks/aas/st_202211
https://www.nxtbook.com/nxtbooks/aas/st_202210
https://www.nxtbook.com/nxtbooks/aas/st_202209
https://www.nxtbook.com/nxtbooks/aas/st_202208
https://www.nxtbook.com/nxtbooks/aas/st_202207
https://www.nxtbook.com/nxtbooks/aas/st_202206
https://www.nxtbook.com/nxtbooks/aas/st_202205
https://www.nxtbook.com/nxtbooks/aas/st_202204
https://www.nxtbook.com/nxtbooks/aas/st_202203
https://www.nxtbook.com/nxtbooks/aas/st_202202
https://www.nxtbook.com/nxtbooks/aas/st_202201
https://www.nxtbook.com/nxtbooks/aas/st_202112
https://www.nxtbook.com/nxtbooks/aas/st_202111
https://www.nxtbook.com/nxtbooks/aas/st_202110
https://www.nxtbook.com/nxtbooks/aas/st_202109
https://www.nxtbook.com/nxtbooks/aas/st_202108
https://www.nxtbook.com/nxtbooks/aas/st_202107
https://www.nxtbook.com/nxtbooks/aas/st_202106
https://www.nxtbook.com/nxtbooks/aas/st_202105
https://www.nxtbook.com/nxtbooks/aas/st_202104
https://www.nxtbook.com/nxtbooks/aas/st_202103
https://www.nxtbook.com/nxtbooks/aas/st_202102
https://www.nxtbook.com/nxtbooks/aas/st_202101
https://www.nxtbook.com/nxtbooks/aas/skywatch_2021
https://www.nxtbook.com/nxtbooks/aas/st_202012
https://www.nxtbook.com/nxtbooks/aas/st_202011
https://www.nxtbook.com/nxtbooks/aas/st_202010
https://www.nxtbook.com/nxtbooks/aas/st_202009
https://www.nxtbook.com/nxtbooks/aas/st_202008
https://www.nxtbook.com/nxtbooks/aas/st_202007
https://www.nxtbook.com/nxtbooks/aas/st_202006
https://www.nxtbook.com/nxtbooks/aas/st_202005
https://www.nxtbook.com/nxtbooks/aas/st_202004
https://www.nxtbook.com/nxtbooks/aas/st_202003
https://www.nxtbook.com/nxtbooks/aas/st_202002
https://www.nxtbook.com/nxtbooks/aas/st_202001
https://www.nxtbook.com/nxtbooks/aas/st_201912
https://www.nxtbook.com/nxtbooks/aas/st_201911
https://www.nxtbook.com/nxtbooks/aas/st_201910
https://www.nxtbook.com/nxtbooks/aas/st_201909
https://www.nxtbook.com/nxtbooks/aas/st_201908
https://www.nxtbook.com/nxtbooks/aas/st_201907
https://www.nxtbook.com/nxtbooks/aas/st_201906
https://www.nxtbook.com/nxtbooks/aas/st_201905
https://www.nxtbook.com/nxtbooks/aas/st_201904
https://www.nxtbook.com/nxtbooks/aas/st_201903
https://www.nxtbook.com/nxtbooks/aas/st_201902
https://www.nxtbook.com/nxtbooks/aas/st_201901
https://www.nxtbook.com/nxtbooks/aas/st_201812
https://www.nxtbook.com/nxtbooks/aas/st_201811
https://www.nxtbook.com/nxtbooks/aas/st_201810
https://www.nxtbook.com/nxtbooks/aas/st_201809
https://www.nxtbook.com/nxtbooks/aas/st_201808
https://www.nxtbook.com/nxtbooks/aas/st_201807
https://www.nxtbook.com/nxtbooks/aas/st_201806
https://www.nxtbook.com/nxtbooks/aas/st_201805
https://www.nxtbook.com/nxtbooks/aas/st_201804
https://www.nxtbook.com/nxtbooks/aas/st_201803
https://www.nxtbook.com/nxtbooks/aas/st_201802
https://www.nxtbook.com/nxtbooks/aas/st_201801
https://www.nxtbook.com/nxtbooks/aas/st_201712
https://www.nxtbook.com/nxtbooks/aas/st_201711
https://www.nxtbook.com/nxtbooks/aas/st_201710
https://www.nxtbook.com/nxtbooks/aas/st_201709
https://www.nxtbook.com/nxtbooks/aas/st_201708
https://www.nxtbook.com/nxtbooks/aas/st_201707
https://www.nxtbook.com/nxtbooks/aas/st_201706
https://www.nxtbook.com/nxtbooks/aas/st_201705
https://www.nxtbook.com/nxtbooks/aas/st_201704
https://www.nxtbook.com/nxtbooks/aas/st_201703
https://www.nxtbook.com/nxtbooks/aas/st_201702
https://www.nxtbook.com/nxtbooks/aas/st_201701
https://www.nxtbook.com/nxtbooks/aas/st_201612
https://www.nxtbook.com/nxtbooks/aas/st_201611
https://www.nxtbook.com/nxtbooks/aas/st_201610
https://www.nxtbook.com/nxtbooks/aas/st_201609
https://www.nxtbook.com/nxtbooks/aas/st_201608
https://www.nxtbook.com/nxtbooks/aas/st_201607
https://www.nxtbook.com/nxtbooks/aas/st_201606
https://www.nxtbook.com/nxtbooks/aas/st_201605
https://www.nxtbook.com/nxtbooks/aas/st_201604
https://www.nxtbook.com/nxtbooks/aas/st_201603
https://www.nxtbook.com/nxtbooks/aas/st_201602
https://www.nxtbook.com/nxtbooks/aas/st_201601
https://www.nxtbook.com/nxtbooks/aas/st_201512
https://www.nxtbook.com/nxtbooks/aas/st_201511
https://www.nxtbook.com/nxtbooks/aas/st_201510
https://www.nxtbook.com/nxtbooks/aas/st_201509
https://www.nxtbook.com/nxtbooks/aas/st_201508
https://www.nxtbook.com/nxtbooks/aas/st_201507
https://www.nxtbook.com/nxtbooks/aas/st_201506
https://www.nxtbook.com/nxtbooks/aas/st_201505
https://www.nxtbook.com/nxtbooks/aas/st_201504
https://www.nxtbook.com/nxtbooks/aas/st_201503
https://www.nxtbook.com/nxtbooks/aas/st_201502
https://www.nxtbook.com/nxtbooks/aas/st_201501
https://www.nxtbook.com/nxtbooks/aas/st_201412
https://www.nxtbook.com/nxtbooks/aas/st_201411
https://www.nxtbook.com/nxtbooks/aas/st_201410
https://www.nxtbook.com/nxtbooks/aas/st_201409
https://www.nxtbook.com/nxtbooks/aas/st_201408
https://www.nxtbook.com/nxtbooks/aas/st_201407
https://www.nxtbook.com/nxtbooks/aas/st_201406
https://www.nxtbook.com/nxtbooks/aas/st_mars
https://www.nxtbook.com/nxtbooks/aas/st_201405
https://www.nxtbook.com/nxtbooks/aas/st_201404
https://www.nxtbook.com/nxtbooks/aas/st_201403
https://www.nxtbook.com/nxtbooks/aas/st_201402
https://www.nxtbook.com/nxtbooks/aas/st_201401
https://www.nxtbook.com/nxtbooks/aas/st_201312
https://www.nxtbook.com/nxtbooks/aas/st_201311
https://www.nxtbook.com/nxtbooks/aas/st_201310
https://www.nxtbook.com/nxtbooks/aas/st_201309
https://www.nxtbook.com/nxtbooks/aas/st_201308
https://www.nxtbook.com/nxtbooks/aas/st_201307
https://www.nxtbook.com/nxtbooks/aas/st_201306
https://www.nxtbook.com/nxtbooks/aas/st_201305
https://www.nxtbook.com/nxtbooks/aas/st_201304
https://www.nxtbook.com/nxtbooks/aas/st_201303
https://www.nxtbook.com/nxtbooks/aas/st_201302
https://www.nxtbook.com/nxtbooks/aas/st_201301
https://www.nxtbook.com/nxtbooks/aas/st_201212
https://www.nxtbook.com/nxtbooks/aas/st_201211
https://www.nxtbook.com/nxtbooks/aas/st_201210
https://www.nxtbook.com/nxtbooks/aas/st_201209
https://www.nxtbook.com/nxtbooks/aas/st_201208
https://www.nxtbook.com/nxtbooks/aas/st_201207
https://www.nxtbook.com/nxtbooks/aas/st_201206
https://www.nxtbook.com/nxtbooks/aas/st_201205
https://www.nxtbook.com/nxtbooks/aas/st_201204
https://www.nxtbook.com/nxtbooks/aas/st_201203
https://www.nxtbook.com/nxtbooks/aas/st_201202
https://www.nxtbook.com/nxtbooks/aas/st_201201
https://www.nxtbook.com/nxtbooks/aas/st_201112
https://www.nxtbook.com/nxtbooks/aas/st_201111
https://www.nxtbook.com/nxtbooks/aas/st_201110
https://www.nxtbook.com/nxtbooks/aas/st_201109
https://www.nxtbook.com/nxtbooks/aas/st_201108
https://www.nxtbook.com/nxtbooks/aas/st_201107
https://www.nxtbook.com/nxtbooks/aas/st_201106
https://www.nxtbook.com/nxtbooks/aas/st_201105
https://www.nxtbook.com/nxtbooks/aas/st_201104
https://www.nxtbook.com/nxtbooks/aas/st_201103
https://www.nxtbook.com/nxtbooks/aas/st_201102
https://www.nxtbook.com/nxtbooks/aas/st_201101
https://www.nxtbook.com/nxtbooks/aas/st_201012
https://www.nxtbook.com/nxtbooks/aas/st_201011
https://www.nxtbook.com/nxtbooks/aas/st_201010
https://www.nxtbook.com/nxtbooks/aas/st_201009
https://www.nxtbook.com/nxtbooks/aas/st_201008
https://www.nxtbook.com/nxtbooks/aas/st_201007
https://www.nxtbook.com/nxtbooks/aas/st_201006
https://www.nxtbook.com/nxtbooks/aas/st_201005
https://www.nxtbook.com/nxtbooks/aas/st_201004
https://www.nxtbook.com/nxtbooks/aas/st_201003
https://www.nxtbook.com/nxtbooks/aas/st_201002
https://www.nxtbook.com/nxtbooks/aas/st_201001
https://www.nxtbookmedia.com