I'm trying to identify a textbook I had briefly and then lost. I had a PDF file of an astronomy textbook, but the hard drive crashed irreparably before I could thoroughly read the textbook, or even record the author and title.

The textbook covered the history of geocentric theories, explained how to make basic astronomical instruments to measure angles, and how to make arguments for heliocentrism. As I recall, the book mentioned that given high-resolution photography, one can prove heliocentrism by measuring how some celestial bodies appear larger at different times of the year.

I am trying to at least work through the calculations for heliocentrism on paper, even if I don't end up crafting my own instruments. If no one knows of any one textbook that covers all these topics, I would still be grateful for relevant textbooks that cover some of these topics.

Update: It is not a complete answer, but a good start can be found with the ephemeris question asked at:



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It's possible the book you seek is by Christopher Graney. I cannot find them now, but I believe he had put together instructions on how to build a telescope similar to what Galileo used and how it could be used to argue for and against a heliocentric universe. But his overall conclusion is that it's poorly suited for the task, and scientists of the time had good reason to not accept it. (E.g. the scope had a very small aperature, and thus a horrible diffraction limit (which they didn't understand at the time). It could measure the planets just fine, but through it, stars also appeared quite large too. Since stars exhibited no detectable parallax, they'd have to be comically huge for the measurements to make sense.)

That said, if you want to actually do it, you don't need any fancy equipment. Almost any telescope off the shelf today will do. You'll need a camera with removable lenses (e.g. a DSLR), but not anything "high res" by today's standards, the oldest used one you can find would be plenty. You'll also need an eyepiece adapter for it (just search for your camera type, e.g. "Canon eyepiece adapter"). You won't need a motorized mount just for the planets.

With that you can take photos of the planets at different times over months, but most likely a least a year or two to get convincing results. Mars will generally show the most dramatic results, and if you search on Google, you'll find plenty of people who've done it.

You can also prove Venus orbits the Sun just by watching its phases. In order to go from full, to half full, to crescent, it has to be on different sides of the Sun than we are during some times. As well as the size change. You'll also find a lot of people have done that if you search for that.

While not showing evidence of a heliocentric universe, one solid piece of evidence Galileo provided in favor of at least a non-geocentric universe was the moons of Jupiter. Even with the limits of his telescope, he was able to show that they orbited Jupiter, so the Earth was not the center of everything. Any telescope of today will be able to see them. Even most binoculars, or even the scope off a rifle.

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    $\begingroup$ Graney's book Mathematical Disquisitions is fascinating, but not the sort of step-by-step how-to book I am looking for. Graney's book Setting Aside All Authority is a little closer to what I am looking for. I fear I will be continuing to search for quite a while. Thanks for your additional informative comments regarding the use of ordinary cameras with Mars and Venus. If I end up abandoning my original plan, I may indeed use cameras as you describe. $\endgroup$
    – Long
    Commented Aug 25, 2019 at 23:28

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