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The “Modern Eddington Experiment”: Spontaneous Emissions
And now for something completely different.
Sometimes, when I try to describe to others what I do as a color scientist, I am asked if I can fix their photos. Usually it is to make their printer look more like their monitor, but a few years ago it was a friend asking about how to correct his underwater pictures while scuba […]
Eddington epilogue
I was lucky to have ended up at this observing location with such excellent weather. When planning to view total eclipses, I am advised to arrange for other activities as well; the eclipse itself is subject to fickle viewing conditions (my one prior total solar eclipse effort was thwarted, but the travel experience was rewarding […]
Discussion
It is a bit disappointing to be unable to show a clear gravitational signal, even with all of the successful exposures that were taken, but I recognized the difficulty of this measurement early on. In addition to the variables I anticipated, there are some additional uncertainties that I now recognize. Here is my updated list […]
Analyzing Eclipse Day Results
I was able to obtain 35 photos during totality that were candidates to locate stars in the field. The exposures ranged from 1/60 to 2 seconds, but it became clear after applying the detection procedure starPos.m, that only the longest exposures, 1 and 2 seconds, would yield detected stars. The inner regions of the corona […]
Comparing Before and During images, step EE-4
This was written prior to eclipse day as I was contemplating how to compare the two image sets. I include it here to keep the thought sequence intact. When we apply steps EE-1, 2, and 3 to both the before images and the during images, we will have a set of radial distances to […]
Monthly Archives: July 2017
Step EE-3: Finding the best fit
We now have a way to transform the stars detected in an image into our virtual camera reference frame, but the previous step was just the “rough alignment” based on two bright stars. This is vulnerable to errors in how … Continue reading
Step EE-2A: A side process to calibrate (radial) lens distortion
Unexpected errors while looking for the best angular fit between the imaged stars and their reference locations. My early efforts to map the imaged stars onto their virtual camera positions showed unexpected errors. They were close, but displayed error … Continue reading
Step EE-2: Transform to reference coordinates
The field of view for my EOS60Da APSC sensor (inner rectangle) and the EOS6D full-frame sensor (middle rectangle). The map overlay is the view from Idaho Falls on the day of the eclipse as displayed by Stellarium (and inverted to … Continue reading
Step EE-1, Detect the star locations in a photograph
It seems easy to locate stars in an astrophotograph: they are the bright dots. I am recording images of the sky with my Canon EOS 60Da. It has a resolution of 5184 x 3456 pixels (after demosaic) in each of … Continue reading
Measuring star deflections, step by step for the Eddington Experiment.
From “Measuring Starlight Deflection during the 2017 Eclipse: Repeating the Experiment that made Einstein Famous,” Donald Bruns Even with high quality equipment, it will be challenging to make measurements of the tiny deflections expected. There are some helpful references available … Continue reading
A plan for 2017, but first, an introduction to celestial coordinates
Astrometry is the term used for measuring the positions of the stars. It has a long history, dating from pre-telescope times, and which has introduced units that may seem archaic, but persist to this day (making them seem both … Continue reading
The “Modern Eddington Experiment”
Images credit: New York Times, 10 November 1919 (L); Illustrated London News, 22 November 1919 (R). Notes and comments on reproducing a famous historical event. Most people today do not know the reference to Sir Arthur Eddington, but he … Continue reading
Spontaneous Emissions 