Foundations of Observational Astronomy: The Moon, the Seasons, and Mapping the Sky
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This is the first lecture series of my online introductory undergraduate Astronomy course. This video series was used at William Paterson University and CUNY Hunter in online classes as well as to supplement in-person course material. Notes and links are present in the videos at the start of each lecture.
0:00:01 - lecture 1: Our Place in Space
0:14:11 - lecture 2: The Celestial Sphere
0:51:01 - lecture 3: The Seasons, the Year and the Day
1:07:05 - lecture 4: Lunacy! Phases, Eclipses and Orbit of the Moon
1:25:11 - lecture 5: Distance, Parallax and Parsecs
1:43:05 - lecture 6: How Round is the Earth? How Far is the Sun?
1:52:26 - lecture 7: I Got the Sun in the Mornin' and the Moon at Night.
2:01:53 - lecture 8: Why did we once think Earth was at the Center?
In the first lecture, I talk about how we navigate our way around the sky. I talk about the constellations and coordinate systems of the sky. (WOOPS! Did you catch that mistake? Yup, I made a couple, but you know I know better. I said "Sun orbits the Earth" once in there. Oh well, I'm trying to talk fast, remember a script, remember the images I put together, and do it all in a quiet room, keeping my energy up and zooming. Wowsers!). In the second lecture, I decided to practice more so you can learn about the Celestial Sphere, equatorial coordinates, and where stars rise and set. Next, I discuss the motions of the Earth and the reason for the seasons. Following this, I discuss the motions of the Moon and the reason for the phases and eclipses. This leads us to discuss the nature of distance in astronomy and its measurement with parallax. Once you know distances, we can chat about how we know the size of the Earth, and how that can be used to determine the distance to the Sun, given that Venus does a transit across the Sun. There's more to do, so I continue my discussion of the nature of distances and sizes in astronomy, and its measurement just positions in the sky. Wherein we chat about how we know the relative sizes and distances of the Sun and Moon to the Earth. Finally, I go back in time to discuss Aristotle's arguments for a stationary Earth, and the construction of Ptolemy's Geocentric Model that ruled the roost for almost 2000 years, until it was dethroned in 1610. - วิทยาศาสตร์และเทคโนโลยี
This is an older video. Please watch the updated version here: th-cam.com/video/oQpKeW_7_NY/w-d-xo.html
I somehow discovered your lectures (thanks TH-cam algorithm) and theyre fantastic!! Im gonna listen to them all. Thank you for making all these videos; theyre excellent!
Yeah the new format is easy to follow. Thanks for sharing the lectures.
At 18:25 Greenwich , suburb of London, England is meant. Greenwich Connecticut is 5 hour s behind GMT ( -4hours when daylight savings time is I effect)
Thanks for the correction!
I think it's great that you're consolidating each module into one video. Thank you!
Fantastic lecture(s), thank you!.
Thanks for all of these!! We all appreciate your hard work teaching us
Indeed.
My pleasure!
Awesome series ✨✨
A great summary!
I was in the middle of no place Colorado when I first looked up and saw the Milky Way.
Awestruck is the only proper description.
I remember looking over the mountains of Northwestern Wyoming, and seeing the stars said all the way to the horizon.
Excellent!
Life-saver.....
Thanks a lot 😊😊😊😊😊😊😊😊😊😊
I remember as a dutchman being lost somewhere in the south of Spain, I found it hard to find the polestar, because the big bear was behind a low hill, and smartfones did not exist. The best starry night I have seen was on a clear night on sea somewhere between Amsterdam and London. Sadly enough in the western part of the Netherlands you can see very little of the night sky, and even on great parts of the north sea you see more light from oil and gas riggs than from celestial objects.
This is our new sad legacy. These stars were where we derived our spirituality and religion. They founded our science. They sourced our artwork. Now we don’t know them at all, but 45 million years of evolution under starry skies is bigger in our psyches than we will ever realize.
@@JasonKendallAstronomer They not only founded our science, but more personally, they saved my life more than once as a small-boat sailor on the west cost of N. America. Even cheap handheld GPS needs batteries, and when they run out in the dark while you're under way, you have only the sky to guide you. My dad (a sailor) taught me well enough for many years that I don't worry a lot about that if I'm good with my charts and the stars. :-)
Sir in RA And Declination measuring do we ignore the proper motion of stars?
That’s a great final exam question!
Thank you sir, I appreciate very much! Finished my first review of this module, wrote down some notes. As I'm not native English speaker from "Eurozone", those pause, rewind, play and playback speed buttons are my friends. BR JKi
Glad it helped!
Hey Jason, I am currently looking at buying a telescope on sale until Nov 20 and was curious to your opinion as this as an entry level telescope. It is the Celestron StarSense Explorer DX 130x650mm Newtonian Reflector.
If you could recommend a better eyepiece of planetary and nebula viewing?
Interesting. It's those tripod legs. They absolutely MUST be stable, or else it's not worth it. Rule of thumb is to spend double to triple on your mount/tripod than the optical tube. If it jiggles, it's no good.
Save money, go with a 6" Dobsonian mount. Much easier to use. I've owned so many different kinds of telescopes, and you would need to spend ~$1500 on just the tripod mount just to get a good experience that won't make you abandon the hobby. My first scope was a 6" Dobsonian. I only sold it because I live in NYC, and hauling it up and down 5 flights of stairs got old. I ended up with a DiscMount and a Televue 102, after going through Celestron 6" and 8" NexStars, and a 15" Obsession UL, and a Takahashi FS-85 Mini. I even had some good times with the tiny Galileoscope, and very large binoculars.
If I had to start over, and I didn't have stairs, I'd stay with the 6" Dob, and a very fine 100mm refractor. This one, Sky-Watcher Classic 150P 6" Traditional Dobsonian Telescope, is almost an exact copy of my first scope. To me, that's quite good.
I would not buy what you're considering. Those tripods are >>always
@@JasonKendallAstronomer Amazing Information and very clear. Going to start looking now :) will keep you posted with where I end up
@JasonKendallAstronomer the one I see is 599.99 and has a circular mount which makes me think this is the table top one your Warning against?
The tabletop ones will be at most $199, and the optical tube length will be about a foot. A typical 6" Dob will be ~4 or 5 feet tall pointing straight up. The base will be round, and about 16 inches wide or so. They will be ~$400 or so. Also, a tabletop dob will always say as much in their product description. Go to the manufacturer's website, or just look for images in the reviews on prominent retailers.
finally, a tabletop Dob will weigh at most 2 to 3 pounds. Proper 6" Dob will be at least 20 pounds.
You rock
A big question I've had is: why do planets (or moons) stay in orbits when eg being hit by meteorites ought to change their speed some (causing a loss of balance). Also, the exact "sweet spot" ought be so small (over hundreds of millions of years), either falling in (more likely) or flying out? There must be another force in play than what Newton explained.
Mark, there is "no other force". The masses of asteroids are so small compared to planets, that impacts make only the tiniest of changes. Yes, when you drive your car, and a big bug hits your windshield, you do slow down a tiny tiny bit, but you can't tell without extraordinarily careful measurements. The same is true with asteroids and meteors. Now, this of course depends on the size of the meteor. The one that killed the dinosaurs would've caused an easily measurable change in at least one of these: Earth's rate of rotation, Earth's orientation of axis of rotation, Earth's orbital parameters. The principle you need to study is called "momentum". You need to look at classical mechanics, and Newton's Laws. There is no need for other physical laws to explain what you're talking about, and whoever might tell you otherwise is trying to sell you something.
@@JasonKendallAstronomer -- thanks for your reply. Isn't an orbit a perfect balancing point though, meaning why ought it remain for billions of years (with things like impacts and other internal planetary things occuring). Perhaps the orbit distance changes some (beside the elliptical orbit)?
@@JasonKendallAstronomer -- if I'm right (falling in), perhaps eventually planets fall in on the star they orbit? I mean there is no force to further eject them out, right? Related, do we know why orbits even start?
It's not a "perfect balancing point", it's just the path that is taken in the presence of a gravitational field. A comet that comes into and out of our solar system from the Oort Cloud is on an orbit, a hyperbolic orbit, but an orbit nonetheless. Impacts made HUGE differences during the formation of the Solar System 4.6 billion years ago, but since then, the occasional (every few million years) big asteroid hit is not enough to move a planet significantly, and make it tumble or move off course. Such changes ONLY exist in the movies, in order to show how one hero can Be The Guy (or Gal). It's not something that "adds up" over time, either. I strongly advise you to look at the classic undergraduate textbook below. It will help you learn about celestial mechanics. The reason you might not be able to find an answer on TH-cam or on the web very easily, (and I'm not being insulting, I'm just letting you know) is because it's a trivial problem that is easily explained by elementary Newtonian Mechanics. www.goodreads.com/book/show/55615165-an-introduction-to-modern-astrophysics-by-bradley-w-carroll-cambridge
Mark, as to your question, when a planet orbits a star, or a space station orbiting a planet, are the same exact thing. And in fact, the planet is falling to the star, it's just moving it laterally so fast that it misses the star. This idea was first hinted at by Galileo and Kepler. Watch my Gravity video lecture module, please. This discussion is not appropriate for this video. Watch that, and move this over there. It's Module #3.
Nitpicking, i know, but 365/24 is approx. 15.2... pretty sure you meant 360/24 = 15
Of the nits that are picked, this one hurts the least. (-;
Sir what about the torque due to the objects going round in the ecliptic and their effect on earth's rotation?
Those effects are extremely minimal and are what is called third order effects. Such torque do exist but they are so tiny as to be swamped by things like earthquakes
@@JasonKendallAstronomer thank you sir
By the same token as a quarter moon, shouldn't a full moon be called a half moon?
Of course, but that opens up the worst possible cisterna lumbricus terrestri. What about a 1/3 moon? A 11/41th moon? A 1/pi moon?
Perhaps the worst thing is that a 1/GrahamsNumber Moon would be in that state for such a short period of time, that a Planck Time would be a stupidly large number by comparison.
1:20:32
This entirely looks unscripted. WOW.
Yes, it was.