Category Archives: Uncategorized

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

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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

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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

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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

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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

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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

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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

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