Astronomy: The basics. How is it done?

[Abba]

I have always been fascinated by astronomy. Unfortunately, I never advanced very far in mathematics. However, I was wondering if some of you cpuld share some general information about how it works without the mathematical formulas.

I was taking a look at a couple of books on sale now on Ebay and they are just fascinating. If I could afford them I would buy them if only to read them once and try to get my money back. There is one that is a basic book full of diagrams. It’s interesting, it reminds me of Stephen Hawking writing for the general public so we could get an understanding of what scientists are doing and he could make a lot of money.

ebay.com/itm/1712-1ed-English-Astronomy-Dials-Sundials-Horology-Science-Physics-ILLUS-/310368942651?pt=Antiquarian_Collectible&hash=item48436e3a3b#ht_3393wt_1161

Then, there is this one: ebay.com/itm/HANDWRITTEN-MANUSCRIPT-1748-Science-Journal-PHILOSOPHY-Astronomy-1st-ED-Antique-/380403392336?pt=Antiquarian_Collectible&hash=item5891cf1f50

It seems as though astronomers make a series of circles around the earth, that have particular measurements, plug in the planets, etc… and are able to determine the course of a comet. Fascinating!

Is this what is called Dialing?

 

[Mwalt]

Those books look really interesting, from a historical perspective, but there have been a lot of advances in astronomy since the 1700s. Just google “astronomy for beginners” and you will find many books (at much more reasonable prices) that will explain the workings of the universe.

At its most basic, I believe scientists use a form of triangulation to determine the distances between planets, which is why transits of Venus were so important a few hundred years ago (the last one of our lifetimes occurred in June). We now know the distances within our own solar system very accurately, but outside the solar system, and especially outside our galaxy, most of the distances are still estimates (+/- 50%, maybe).

 

[greylorn]

I was taking a look at a couple of books on sale now on Ebay and they are just fascinating. If I could afford them I would buy them if only to read them once and try to get my money back.

There actually is a way to read good books for free without chiseling someone and wasting their time to save a few bucks.
Consider searching the internet for the meaning of the word, library.

 

[Abba]

There actually is a way to read good books for free without chiseling someone and wasting their time to save a few bucks.
Consider searching the internet for the meaning of the word, library.

Listen Mr. Grumpy, I was not thinking of chiseling someone nor wasting their time. It would be more that I would buy the book and try to resell it at some point. Not necessarily to the person I bought it from.

Hey, so what do you think about that new discovery? Ooops. We need to behave now. That would be off-topic. Never mind.

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Why do astronomers use the reference to the zodiac signs?

http://img.auctiva.com/imgdata/1/4/1/4/8/5/8/webimg/483484899_o.jpg

I just think that it is fabulous that they can calculate the trajectory of a comet. Pretty cool. That’s how Descartes did it but he did not want to share with anyone so the world would admire him. He loved the glory.

How does this work?

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[greylorn]

Listen Mr. Grumpy, I was not thinking of chiseling someone nor wasting their time. It would be more that I would buy the book and try to resell it at some point. Not necessarily to the person I bought it from.

Maybe you should listen up, Ms. Annoyingly-Cheerful. That last sentence was totally equivocal. Phrases such as, “more like,” “try to resell,” and “not necessarily” are gutless, non-committal comments. A statement like, ‘I will never try to get the person from whom I bought the book to take it back,’ would show some integrity. Remind me never to sell you a book.

At least you appear to have a sense of humor. The last time I got chiseled out of $1500 I felt a whole lot better about the loss, knowing that the guy who cheated me had a good laugh over it.

Hey, so what do you think about that new discovery? Ooops. We need to behave now. That would be off-topic. Never mind.

Back in 1962 when the Bevatron was a big deal I predicted that every new particle accelerator would find something new. It is not about the physics, but entirely about the money.

If you have a pack of hunting dogs, they need to be fed. Their best strategy for getting fed is to convince you that there is something in the tree that they are barking up, even if you cannot possibly see it.

Why do astronomers use the reference to the zodiac signs?

They don’t. You will not find that goofy old astrologer’s diagram in a modern astronomy book, except perhaps as an historical reference.

Modern cataloging systems have adapted to the variety of objects visible (and invisible but detectable). E.g:
hubblesite.org/gallery/album/the_universe

I just think that it is fabulous that they can calculate the trajectory of a comet. Pretty cool.

Newton figured out the equations a few centuries back. Most are analytically insolvable, but every Numerical Analysis 101 course explains how to solve them on your home computer.

That’s how Descartes did it but he did not want to share with anyone so the world would admire him. He loved the glory.

Where on earth did you get that absurd, nonsensical drivel from? A comic book? Or did you make it up?

Of all the ignorant posts I’ve read on CAF, my own included, that one wins the booby prize. Maybe you should consider going to the elsewhere-mentioned library and reading stuff not written by nitwits on food stamps who supplement their incomes by volunteering for stupid-pill testing.

Descartes made no such calculations. He invented analytic geometry and the Cartesian coordinate system which provided a framework for Newton’s subsequent calculus-based computations. Descartes made his writings freely available, except for those deep philosophical inquiries which he knew would get him a personal chamber in the nearest Inquisitorial Hotel.

How does this work?

http://i241.photobucket.com/albums/...qZnUE63Tf7ptUBO06pqwLZg60_57.jpg?t=1341353170

Whatever it is, it does not “work.” It just sits there to baffle the confused mind. .

 

[Abba]

greylorn;9485213:

Where on earth did you get that absurd, nonsensical drivel from? A comic book? Or did you make it up?

Of all the ignorant posts I’ve read on CAF, my own included, that one wins the booby prize. Maybe you should consider going to the elsewhere-mentioned library and reading stuff not written by nitwits on food stamps who supplement their incomes by volunteering for stupid-pill testing.

Descartes made no such calculations. He invented analytic geometry and the Cartesian coordinate system which provided a framework for Newton’s subsequent calculus-based computations. Descartes made his writings freely available, except for those deep philosophical inquiries which he knew would get him a personal chamber in the nearest Inquisitorial Hotel.

Well, I’ll have you know that Descartes did determine a comet would be passing by and he impressed everyone and kept the math to himself to indulge in glory. He also had in front of his house a mechanical gadget to impress impress people. Given his character, I do not know that his ability to predict the passing of that comet was totally his. I will have to research this matter further to provide you with proof. I will return to the thread. However, right now I have to work as I have bills to pay.

Look at Descartes’ character:

World of Mathematics on Willebrord Snell
Willebrord Snell is best known for his discovery regarding the refraction of light rays. This discovery, known as Snell’s law, demonstrates that when a ray of light passes from a thinner element such as air, into a denser element, such as water or glass, the angle of the ray bends to the vertical. Snell’s law–a key revelation in the science of optics–was formulated after much experimentation in 1621. This is expressed as sin i = sin r (i=angle of incidence, r=angle of refraction and = a constant). However, he did not publish his findings, and the law did not appear in print until René Descartes discussed it (without giving Snell credit) in his Dioptrique in 1637. Snell also determined a formula to measure distances using trigonometric triangulation. His method, developed in 1615, used his home and the spires of Leiden churches as reference points. (In 1960, a plaque recognizing his work was placed on his home.) In an age of world exploration, this was very important work, because it contributed to improved accuracy in the art of mapmaking. Using the triangulation method, Snell measured the Earth’s meridian for the first time, and also attempted to measure the size of the Earth using this method. He set down the principles of spherical trigonometry that determine the length of a meridian arc when measuring any base line. Snell’s writings on his triangulation method were presented in Eratosthenes batavus (1617). His observations of comets sighted in 1585 and 1618 are described in his Cyclometricus de circuli dimensione (1621). His last works, Canon triangulorum (1626) and Doctrina triangulorum, published after his death in 1627, also addressed the measuring of distances through plane and spherical trigonometry. bookrags.com/biography/willebrord-snell-wom/

I can tell you that Snell’s work is put to use today. How non–detectable missiles and drones etc… are built is by light and heat defraction/ diffraction (and deflection of sound waves)which goes back to Snell- although the mechanism and components are of a more modern conconction, but, the principle I think is Snells.I think Descartes would not have stopped at plagiarism to enjoy the glory. Why did he not give credit to Snell?

Anyhow, he did determine a comet would be going by and when it did people were amazed and admired him with amazement. He enjoyed every minute of it. I have to question his originality though. The info is not readily available on google so I will have to do some research…but rest assured that I will be back with it.

 

[Abba]

Oh, my goodness. In my search this thread came up. I write unconscious that any body and every body can read the posts. Wow! It’s instant publication worldwide.

Nonetheless, I even searched in french, thinking definitely the french would have some info. I did not find any reference to Descartes prediction of a comet nor of the mechanical gadget he had in front of his house.

All I found was that he did work with comets and thought that a comet was a star that had become detached from its orbit.

Newton disagreed with Descartes understanding about a comet being a detached star and I do not see how Descartes given his misunderstanding could predict the trajectory of a comet. I think three did go by during his life time.

Well, if anyone ever finds any information on Descartes predicting a comet and having some mechanical gadget in front of his house, please post here.