newbie : Where to find Information

cullsin commented 1 year ago

Hi,

I am a newbie into this group. The one side of the coin is pure astro math's. The other side of the coin is that interpret towards human's life. Please suggest where I can find information about that connection's and tutorial?

Thanks, Raja K

cosinekitty commented 1 year ago

Astronomy Engine is designed purely for calculation of physical behavior of solar system objects, coordinate conversions, etc. Everything in it is verified in comparison with authoritative reference sources. I am not a believer in astrology, so I am probably the wrong person to ask about that second part!

cullsin commented 1 year ago

Thanks. Let me find that appropriate source. I wish you believe astrology :-) / Someone connects may be the fundamental of about 60% . Rest can be queried for good. Astrology is good, but not astrologers. They dilute themselves by throwing different predictions.

cullsin commented 1 year ago

Hi,

According to astrology, there are 27 constellations. certain constellation belongs to certain planet. Is this real as of today?

I have a limited knowledge and I do not have any one to educate. So please don't mind about my questions

Raja K

cosinekitty commented 1 year ago

The planets appear to be in a given constellation at a given time as seen from the Earth. Observers somewhere else in the solar system (another planet or a spacecraft far from Earth) will see the planets in different constellations because they are observing from a different angle. I can't think of what it would mean to say a planet belongs to a constellation in any permanent sense.

Constellations themselves are artificially constructed regions of the sky. In 1922, the International Astronomical Union (IAU) agreed upon 88 constellations that astronomers use for conveniently mentioning various regions of the observable sky. Astronomers have continued to use these rectilinear borders to this day. The 88 IAU constellations are what Astronomy Engine uses in its Constellation function, which allows you to know what constellation any point in the sky belongs to, given its right ascension (RA) and declination (DEC).

I personally don't think constellations mean anything. They are random patterns of stars that happen to vaguely resemble different things to different cultures over time. We know that stars we see are all orbiting the galaxy at different speeds and moving in different directions. Over the span of hundreds of thousands of years, all of these patterns we see will change and become unrecognizable from their current arrangement. Ascribing human-oriented meanings to them would be like some tiny creature who lives for a few minutes seeing clouds in the sky, deciding to name them, and believing they mean something about itself and its fellow tiny creatures.

cullsin commented 1 year ago

Hi,

I am looking into the planet's position for the given latitude and longitude of an earth.
http://cosinekitty.com/solar_system.html

I need coordinates for the Sun as well. Your solar system web page needs to show that information. Please suggest. Also, Please advise which method from the astronomy engine gives this information. I did not find any samples.

Please suggest.

Raja K

cosinekitty commented 1 year ago

That Solar System calculator uses a much older set of formulas for calculating positions, so it is not nearly as accurate as Astronomy Engine. However, it does show the Sun above all the planets. See here:

In Astronomy Engine, take a look at the positions.js demo. It shows how to do this same thing.

cullsin commented 1 year ago

Thanks. Can you please suggest a method in the astro engine module that returns the planet positions?

Raja K

On Tue, 28 Feb, 2023, 6:42 pm Don Cross, @.***> wrote:

That Solar System calculator uses a much older set of formulas for calculating positions, so it is not nearly as accurate as Astronomy Engine. However, it does show the Sun above all the planets. See here:

[image: image] https://user-images.githubusercontent.com/11699954/221864076-e23172d6-be14-43aa-af82-0ba3841b306b.png

In Astronomy Engine, take a look at the positions.js https://github.com/cosinekitty/astronomy/blob/master/demo/nodejs/positions.js demo. It shows how to do this same thing.

— Reply to this email directly, view it on GitHub https://github.com/cosinekitty/astronomy/issues/286#issuecomment-1448155603, or unsubscribe https://github.com/notifications/unsubscribe-auth/ABHGJPVUOZHT5CBLCVQ5AGLWZX2SNANCNFSM6AAAAAAUTAMMLI . You are receiving this because you authored the thread.Message ID: @.***>

cosinekitty commented 1 year ago

That same positions.js demo shows the Sun, Moon, and planets:

$ node positions 30.5 -90.7 
UTC date = 2023-02-28T13:31:55.643Z

BODY           RA      DEC       AZ      ALT
Sun         22.73    -8.06   106.88    12.19
Moon         5.49    26.26     8.16   -32.33
Mercury     21.91   -14.95   120.01    17.76
Venus        0.62     3.24    82.41    -5.55
Mars         5.16    25.35    13.61   -32.41
Jupiter      0.73     3.51    81.30    -6.87
Saturn      22.10   -13.07   116.71    16.83
Uranus       2.86    16.07    51.01   -24.39
Neptune     23.68    -3.37    95.30     2.85
Pluto       20.12   -22.62   146.29    28.83

cullsin commented 1 year ago

Hi,

I run the script for the given input. It is not matching with my planet positions mentioned in one of the astrology platform ( astrosAge app) . I have attached the screen shot for your refence.

When I run the command, I got the below result. node positions.js 10.786 79.137 1981-08-07T23:10:00.000Z

Note : * When you debug or try to match my result, please do the % operation of 30 degree. For example if sun is in 70 degree then in my chart it shows as 70 % 30 = 10 degree as per my calculation

BODY RA DEC AZ ALT Sun 9.20 16.16 68.12 -19.55 Moon 15.06 -12.11 264.55 -67.59 Mercury 9.07 18.49 66.43 -16.97 Venus 11.27 6.02 65.18 -51.70 Mars 7.02 23.40 68.03 11.62 Jupiter 12.49 -1.90 61.42 -71.71 Saturn 12.45 -0.46 58.51 -70.47 Uranus 15.60 -19.13 250.73 -58.97 Neptune 17.46 -21.89 250.82 -32.54 Pluto 13.78 7.05 348.79 -71.59

info

cosinekitty commented 1 year ago

I think two things are happening:

Your screenshot does not show the same time as you gave to positions.js. Or at least I can't tell what time and date you gave it. Can you double check this? Also make sure you are correcting between UTC and your local time, if needed.
More importantly, I suspect the "Degree" number is an ecliptic longitude, not an equatorial right ascension (RA) or declination (DEC).

Assuming you want geocentric ecliptic longitudes, not heliocentric longitudes, here is an example of how to calculate that:

const Astronomy = require('./astronomy.js');

const observer = new Astronomy.Observer(10.786, 79.137, 0.0);
const time = Astronomy.MakeTime(new Date('1981-08-07T23:10:00.000Z'));
const bodyList = [
    Astronomy.Body.Sun,
    Astronomy.Body.Moon,
    Astronomy.Body.Mercury,
    Astronomy.Body.Venus,
    Astronomy.Body.Mars,
    Astronomy.Body.Jupiter,
    Astronomy.Body.Saturn,
    Astronomy.Body.Uranus,
    Astronomy.Body.Neptune,
    Astronomy.Body.Pluto
];

console.log(`Body      Longitude    Latitude`);

for (let body of bodyList) {
    // Calculate J2000 equatorial coordinates of the body as seen from the Earth.
    const equator = Astronomy.Equator(body, time, observer, false, true);

    // Convert equatorial coordinates to ecliptic coordinates.
    const ect = Astronomy.Ecliptic(equator.vec);

    console.log(`${body.padEnd(8)} ${ect.elon.toFixed(3).padStart(10)} ${ect.elat.toFixed(3).padStart(11)}`);
}

The output looks like this:

Body      Longitude    Latitude
Sun         135.330      -0.000
Moon        226.697       4.992
Mercury     132.814       1.662
Venus       167.313       1.203
Mars        103.744       0.698
Jupiter     187.252       1.178
Saturn      186.174       2.284
Uranus      236.056       0.203
Neptune     262.266       1.339
Pluto       201.921      16.889

cullsin commented 1 year ago

Hi,

I am so sorry for the confusion. I gave you the wrong time & date. I did not notice UTC.

I need a degree calculation from the given latitude and longitude from the earth. Below is the data for my planet's position Place: Thanjavur, Tamilnadu, India ( latitude - 10.786, longitude - 79.137, 0.0 ) Time : July 8th 1981, 11:10 PM IST Timezone

Please suggest the planet's position with the attached image above.

cosinekitty commented 1 year ago

I'm confused because the code sample I showed does calculate the position for a given observer on the Earth. You now have examples for planet positions expressed three different coordinate systems: horizontal, equatorial, and ecliptic. Is there some other orientation system you need? I think you need to get clarity on exactly what you are doing; otherwise, it is hard to help you.

cullsin commented 1 year ago

I am sorry for the confusion; I did not do anything. I just ran the Date of birth, latitude, and longitude in the astrology app astrosage and attached the image above. These calculations are similar across most of the platforms in astrology. Your recent output has only latitude, longitude and no planetary positions.

I got the online website below https://instaastro.com/vedic-astrology/planetary-positions/

Can you please replicate the same results through our script or code?

cosinekitty commented 1 year ago

Your recent output has only latitude, longitude and no planetary positions.

Those numbers are ecliptic latitudes and longitudes, and they are planetary positions, expressed ecliptic coordinates. I was trying to help by providing a third coordinate system to use. In total I have shown you how to calculate planet positions in three different systems:

Horizontal (altitude, azimuth based on given observer's horizon)
Equatorial (right ascension, declination based on the plane of the Earth's equator)
Ecliptic (latitude and longitude referenced to the Earth's orbital plane)

Yet you keep saying I am not showing you how to calculate planet positions, which is frustrating.

Astronomy Engine is available for anyone to use, and I'm willing to help explain how it works and to solve problems with it. I'm also happy to help explain astronomy concepts. This is my act of public service in the spirit of fostering scientific education.

However, I have a policy of not doing people's work for them. I feel like you are not really clear on what you are trying to calculate, but you just want answers that match what some other program calculates, and you want me to figure it out for you without you understanding it. This is outside my mission statement.

I think if you spent some time learning more about astronomy coordinate systems and work through some calculations, and by trial and error compared your results to the other programs, you could figure this out.

cullsin commented 1 year ago

Yet you keep saying I am not showing you how to calculate planet positions, which is frustrating.

I'm sorry, but you have mistaken me. You're showing a result. But I need to match the result from the Actual Results shown on this website so that I understand the direction to proceed.

https://instaastro.com/vedic-astrology/planetary-positions/

However, I do not do people's work for them. I feel like you are not really clear on what you are trying to calculate, but you just want answers that match what some other program calculates, and you want me to figure it out for you without you understanding it. This is outside my mission statement.

Again. I do not want to confuse you with an example or wrong information. So I shared the website to ease your finding. I did compare the results. Since it is not showing the correct number, I reach out to you.

cullsin commented 1 year ago

Can you please direct me? I am waiting for your response.

cosinekitty commented 1 year ago

I don't know what coordinate system these other programs are using. When I see something like "FullDegree", it doesn't tell me anything. There are an unlimited number of different orientations that someone could use to describe a point in the sky. That is the most important thing you need to figure out.

It is most likely a form of ecliptic longitude. I suggest trying a few calculations for a given planet at times a few weeks apart. Something distant like Jupiter or Saturn will eliminate sensitivity to time zones or location on the Earth. Record the results, perhaps in a spreadsheet. Then calculate ecliptic longitudes for the same planet at the same times using Astronomy Engine as I showed above. The numbers may be very different, but perhaps there is an offset of some kind between them. Try subtracting the respective numbers and see if there is a pattern. You would be looking for a difference between the two that is consistent over time.

If that doesn't work, I would then try equatorial longitude, which is called right ascension (RA). Keep in mind that Astronomy Engine calculates RA in sidereal hours. You need to multiply by 15 to convert to degrees.

If all else fails, try getting some graph paper and a protractor and start plotting things on it, using numbers from both Astronomy Engine and the other programs. It could be that seeing the angles physically represented rather than looking at numbers will reveal some insight.

Also, you could try looking to see if there is some reference source that explains what these numbers mean. If you don't know what they mean (and I certainly don't), there is little chance of calculating them.

cosinekitty / astronomy

newbie : Where to find Information #286