Repeating
the Experiment that Made Einstein Famous
An
attempt to measure the solar deflection of stars during the August 21, 2017
total solar eclipse to the highest precision ever realized.
Commercial
equipment today is better than ever!
Society
for Astronomical Sciences, Ontario, CA, USA June 2016: Presentation Abstract
In 1919, astronomers performed an experiment
during a solar eclipse, attempting to measure the deflection of stars near the
sun, in order to verify Einstein’s theory of general relativity. The experiment was very difficult and
the results were marginal, but the success made Albert Einstein famous around
the world. Astronomers last
repeated the experiment in 1973, achieving an error of 11%. In 2017, using amateur equipment and
modern technology, I plan to repeat the experiment and achieve a 1% error. The best available star catalog will be
used for star positions.
Corrections for optical distortion and atmospheric refraction are better
than 0.01 arcsec. During
totality, I expect 7 or 8 measurable stars down to magnitude 10, based on
analysis of previous eclipse measurements taken by amateurs. Reference images, taken near the sun
during totality, will be used for precise calibration. Preliminary test runs performed during
twilight in April 2016 and April 2017 can accurately simulate the sky conditions
during totality, providing an accurate estimate of the final uncertainty.
(Click
here to download the technical paper.)
Ctrl+click here to open a new window and view the video
presentation on YouTube (Note
the video was taken with an infrared camera to keep the room dark, so my visual
appearance is a little funny!)
A
feature article for Sky & Telescope
Magazine appeared in the August 2016 issue, with additional description on
their web site.
(www.skyandtelescope.com/sky-and-telescope-magazine/beyond-the-printed-page/my-do-it-yourself-relativity-test/)
Tele
Vue Optics, one of my sponsors, has been posting my progress on their own web
pages. Click here to read their stories
about me: http://bit.ly/TVOEMNP101isRel3
Data
Analysis of Eclipse Images
December
23, 2017
By
subtracting a blurred corona from each of the 34 images (0.62 second
exposures), then combining all of them with a small translation, 18 very
accurate, but dim, stars are measureable.
Combining the 11 shorter images (0.09 seconds) allowed me to measure the
two stars that are close to the sun, and use other stars in those mages to get a
good alignment. A total of 20 stars
are included in my final results.
The left figure shows the image with the 0.62 sec exposures, the center
figure shows the star positions indicated with the white circles, and the right
figure shows the image with 0.09 sec exposure. Based on the location of the two
close-in stars, the exposures were just about perfect!
I
was originally hoping to see 8 stars that would be bright enough to get good
data (Eddington based his analysis on only 5 stars in 1919!). The data shows me many more stars, so I
am convinced that my final results will be much better. (Click here to see Mathcad
program example.)
Presentations
and publications:
Society
for Astronomical Sciences, paper and lecture, completed June 2016.
Sky
& Telescope Magazine, article published August 2016.
Sky
& Telescope Magazine special Eclipse issue, August 2017.
Reference
to the S&T
article
Reference
to the S&T
article
Sky
& Telescope News
blog
“Using
Arago’s spot to monitor optical axis shift in a Petzval refractor”,
D.G. Bruns, Applied
Optics Vol. 56, #8, pp. 2074-2077 (2017).
“Astrometric
distortion calibration of a portable refractor”, D.G. Bruns and C.T.
Bruns, Applied
Optics Vol. 56, #8, pp. 6288-6292 (2017).
Discover
Magazine blog,
interview posted May 5, 2017
Astronomy
Magazine list
of cool experiments, posted May 15, 2017.
Article
in Live
Science blog, July 26, 2017;
NASA blog
Universe
of Learning: A presentation from Sonoma State
Hackaday blog, August 16, 2017
Presentation
at AstroCON, August 17, 2017, in Casper, WY. About 400 amateur astronomers in
the audience.
Repeat
presentation on August 18 at the Lion’s Camp for interested students and
astronomers.
Setting
up on Casper Mountain, video by Canon
SHSU
Student blog
Newsweek
mentions the experiment
Astronomy
blog posted after the eclipse
Story in the Colorado Springs Gazette-Telegraph Newspaper about me and my brother getting ready for the eclipse, performing this experiment and one other
Final
paper in draft form (with small errors to be corrected in the final published
paper) is available at arxiv.org.
Classical
and Quantum Gravity blog
Just
Science blog
CloudyNights forum
AAS blog
Inside
Science blog
Very
nice Tele Vue blog from NEAF,
with lots of photos.
NEAF talk,
April 21, 2018 raw version before editing.
See Day 1, third talk. About 500 amateur astronomers in the audience.
Cosmic
Perspective Radio interview by Andy Poniros at NEAF
on WPKN radio 89.5FM
Final
eclipse report, 2018, published by Classical and
Quantum Gravity, on March 6, 2018 (Vol 35, No. 7, 12 April 2018).
Follow-up
article in Sky & Telescope magazine in August 2018, and on their web page
at SkyandTelescope.com.
“Sky
brightness and color measurements during the 21 August 2017 total solar eclipse”,
D.G. Bruns and R. D. Bruns, Applied
Optics Vol. 57 #16, pp. 4590-4594 (2018).
Astro-Imaging
Channel on YouTube, discussion of my experiment by Bob Denny, author of one
of the software packages I used. He
talks about my experiment for 7 minutes.
A
German
astronomy web blog, with an article in the September 2018 print issue.
Physics
Today had a 1-year anniversary summary of Eddington’s experiment,
featuring my results.
Science
News had a 1-year anniversary summary of Eddington’s experiment, a
shorter version of the Physics Today blog.
Discussed
in an interview
by Prof. Duncan (CU-Boulder) on Colorado Public Radio.
Included
in “Theory and Experiment in Gravitational Physics” (Second
Edition), a book by Clifford Will, published in 2018.
Invited lecture at the American
Association of Physics Teachers conference in Houston in January 2019.
About 100 physics teachers in the audience.
Invited lecture at the American Physical Society
conference in Denver in April 2019.
About 150 physicists in the audience, including Kip Thorne (Nobel winner
2017).
Very
nice review of the APS Denver talk on the Forbes
weblog, “One Hundred Years of Gravity Bending Light,” by Chad Orzel.
Still
to come:
Included
in O Eclipse de Einstein [Einstein’s eclipse], a book by Prof. Nuno Crato and Prof. Luís Tirapicos, to be
published in 2019 in Portugal.
Possible
mention in IMAX Einstein documentary movie 2019 (release may be delayed until
2020).
Acknowledgements:
Al
Nagler, Tele Vue Optics, Inc., for loan of the NP101is telescope and optical
raytracing.
Greg
Terrance, Finger Lakes Instrumentation LLC, for loan of the ML8051 CCD camera.
Stephen
Bisque, Software Bisque, Inc., for loan of the MyT Paramount tripod.
George
Kaplan and John Bangert, both formerly of USNO, for astrometric advice and help
with NOVAS.
Norbert
Zacharias, USNO, for astrometric advice.
This
research has made use of FORTRAN version of NOVAS, the Naval Observatory Vector
Astrometry Software package.
This
research has made use of the VizieR catalogue access tool, CDS, Strasbourg,
France. The original description of the VizieR service was published in A&AS 143, 23.
Suresh
Rajgopal, for help in setting up gfortran.
Corey
Bruns, for help in automating the data analysis with linear algebra advice.
Ted
Pecoraro, for help in improving the Paramount field tripod feet.
Steve
Lang, for help setting up in Wyoming.
Jerry
Kassebaum, for suggesting locations near Casper.
Greg
Kinne, for help in scripting TheSky.
Ron
Bruns, for calibrating weather instruments and operating an auxiliary
experiment.
Thank you for your interest in Stellar Products!
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2005-2019 by Don Bruns
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Web page last updated April 21, 2019.