POSS-II / STSCI / CALTECH / PALOMAR OBSERVATORY
PINWHEEL PERFECTIONby Alan Whitman
14 JUNE 2020 • SKY & TELESCOPE
I
tear out many of the observing articles in Sky & Telescope
to use as guides whenever a superb night might present
itself, and I add them to my ever-thickening observing
folder. But not every month offers a superb night at my lati-
tude of 49 ° north, even though I live in the semiarid Okana-
gan Valley of southern British Columbia, on the drier and
clearer eastern side of the Cascade Mountains. The June sec-
tion of my observing folder contains several articles that I dip
into often. This June will be no exception. I’ll turn to some
of my favorite articles on a stunning spiral galaxy in the far
eastern reaches of Ursa Major: M101. Join me as we acquaint
ourselves with this magnifi cent object and its surroundings.
Diving into M101’s Spiral Arms
The June 1993 issue of Sky & Telescope featured the article “A
Visual Tour of M101” by amateur astronomer Roger N. Clark,
who used to observe at an excellent site in the Colorado
Rockies. M101 is a spiral galaxy that displays a mixture of
A Galaxy-Hop
Around M
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Take a telescopic tour of the Pinwheel Galaxy and its neighbors.
BRIMMING WITH H II REGIONS
The author tackled the H II regions
in the spiral arms of M101, and on
his fi rst visit identifi ed three knots.
Two subsequent tours of the outer
arms of the galaxy revealed a
further seven knots.
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