Tropic of Cancer, Tropic of Capricorn


Forrest Erickson
 

Some years ago I worked up a program about the zodiac mnemonic.
Remember it?
Who does?

For that program I configured Cartes du Ciel for ecliptic coordinate system and set the ecliptic in the center of the screen producing an image similar to this one. 

This is set up for just last week or so when we were at the summer solstice.
The green line in the center is the ecliptic. The heave blue line what goes above and below is the celestial equator. Notice the sun left of center is highest above the equator where the sun is in the feet of Gemini.   This is about right on top of M35 an open cluster and I heard it once that M35 is like a soccer ball kicked by Castor.

Back at the end of the bronze age at about 1177 BCE due to the precession of the equinox, sky was different.

Notice that now the sun is highest when it is in Cancer.  If you were 23 degrees north of the equator the sun would be right over head on about June 21.

You are standing on the line we call the tropic of Cancer to this day.

If we had been updating the navigation vocabulary we would now call it the tropic of Gemini. 

What would we call the one in December?



Patrick, Edward L.
 

Tropic of the Unicorn?

 

I would have been interesting to see the planets in Orion and Pegasus. Quite a different backdrop for the cosmic tapestry.

 

Best regards,

 

 

Ed

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Edward L. Patrick

Lead Scientist

Space Science & Engineering Division

Southwest Research Institute

210.522.5398

epatrick@...

swri.org

 

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From: smokymtnastro@groups.io <smokymtnastro@groups.io> On Behalf Of Forrest Erickson
Sent: Monday, July 4, 2022 12:23 PM
To: SmokyMountainAstronomicalAssociationGroupsIO SMAS <smokymtnastro@groups.io>
Subject: [smokymtnastro] Tropic of Cancer, Tropic of Capricorn

 

[EXTERNAL EMAIL]

Some years ago I worked up a program about the zodiac mnemonic.

Remember it?

Who does?

 

For that program I configured Cartes du Ciel for ecliptic coordinate system and set the ecliptic in the center of the screen producing an image similar to this one. 

This is set up for just last week or so when we were at the summer solstice.

The green line in the center is the ecliptic. The heave blue line what goes above and below is the celestial equator. Notice the sun left of center is highest above the equator where the sun is in the feet of Gemini.   This is about right on top of M35 an open cluster and I heard it once that M35 is like a soccer ball kicked by Castor.

Back at the end of the bronze age at about 1177 BCE due to the precession of the equinox, sky was different.

Notice that now the sun is highest when it is in Cancer.  If you were 23 degrees north of the equator the sun would be right over head on about June 21.

 

You are standing on the line we call the tropic of Cancer to this day.

 

If we had been updating the navigation vocabulary we would now call it the tropic of Gemini. 

What would we call the one in December?

 

 


Don Schoenhofer
 

Tropic of Sagittarius?


Forrest Erickson
 

That would be my take on it. 

On 07/05/2022 2:32 PM Don Schoenhofer <donschoenhofer60@...> wrote:


Tropic of Sagittarius?