Measuring angles with your hands, photograph by the Author.
Due to technical difficulties, our regularly scheduled
program, “The Peculiar Tale of Dr. Blank, Part Two ©”, has
been delayed – Author’s Note
Astronomers
measure the night sky in degrees of angular separation. Since, there are 360o in a circle, the
degrees of angular separation between any point on the horizon and to a point
halfway between the horizon and directly overhead is 45o and to a
point directly overhead, or at the zenith, 90o.
You
can use your fingers and your hand to estimate the degrees of distance between
objects in the sky. With your arm fully
extended, hold out your hand and close one eye.
Now holding your hands like in the picture above, estimate the degrees
of separation between objects you are looking at. Don’t forget you can use two hands to combine
distances, so one fist and three fingers equals 15o (three fingers,
or 5o, plus one fist, or 10o, equals a total of 15o)
of angular separation.
Figure 6, from the Book of Stars, adapted by the Author.
You
can use the stars of “Big Dipper”1 to see how closely your fingers
estimate degrees of angular separation, by comparing them to the known degrees
of distance between the stars of this constellation.
An excerpt from “A ‘Handy’ Way To Measure The Sky”, by NC Science Festival, HERE.
To
use the stars of this constellation to check the accuracy of your fingers, first
measure your index, middle and ring finger combined
against the distance of the two pointer stars, Dubhe and Merak, which is 5o. Second measure the distance between Dubhe and
Megres, the first star of the Big Dipper’s handle, your fist, the degrees of
separation between the two is 10o.
Third, estimate the distance between Dubhe and Mizar, which is the third
star in the handle, by using the distance between the end of your index
finger and the tip of your pinkie, the actual degree of angular separation is
about15o. And finally, the
distance between Dubhe and the last star of the Big Dipper’s handle, which is
Alkaid (also known as Benetnasch) can be estimated by the distance between the
end of your pinkie and the tip of your thumb and is 25o.
And
you can use your hands to measure other things as well?
Don’t forget to come back
next week and read “The Peculiar Tale of Dr. Blank,
Part Two ©”, where we will further investigate this peculiar historical
whodunit! Now that we now know who our mysterious doctor was,
can we be certain that he served with the Massachusetts levies in 1755 and then
later with Roger’s Rangers?
I
hope that you continue to enjoy The Woodsman’s Journal Online and look for me
on YouTube at BandanaMan Productions for other related videos, HERE. Don’t forget to follow me on both The
Woodsman’s Journal Online, HERE,
and subscribe to BandanaMan Productions on YouTube. If you have questions, as always, feel free
to leave a comment on either site. I
announce new articles on Facebook at Eric Reynolds, on Instagram at
bandanamanaproductions, and on VK at Eric Reynolds, so watch for me.
That
is all for now, and as always, until next time, Happy Trails!
Notes
1 The
“Big Dipper”, is also called Ursa
Major, the “Great Bear”, or in the United Kingdom, “The Plough”.
Sources
Air
Ministry, The Air Ministry Survival Guide, [Michael Joseph, Penguin
Random House, UK, 2018], pages 111-113
Body Ruler; “Measuring
Angle and Distance with your Thumb”, http://www.vendian.org/mncharity/dir3/bodyruler_angle/,
August 23, 2022
MathIsFun; “Estimate How
Far Away”, [© 2017 MathsIsFun.com], https://www.mathsisfun.com/measure/estimate-distance.html,
August 23, 2022,
NC Science Festival, “A
‘Handy’ Way To Measure The Sky”, [© 2016 The University of North Carolina at
Chapel Hill], https://ncsciencefestival.org/sites/default/files/documents/SSP_Handy%20Way%20to%20Measure%20the%20Sky.pdf,
August 31, 2022
Skwarecki, Beth; “How to
Estimate Distance Using Just Your Thumb”, August 3, 2022, [© 2022 G/O Media
Inc.], https://lifehacker.com/how-to-estimate-distance-using-just-your-thumb-1849365952,
August 23, 2022
Shepard, Lesley; “How to
Estimate Measurements Without a Ruler or Tape Measure”, October 6, 2019, [The
Spruce Crafts is part of the Dotdash Meredith publishing family], https://www.thesprucecrafts.com/ways-to-measure-without-ruler-2366642,
August 23, 2022
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