B Is there a standard mapping of celestial coordinates to geo-coordinates

Sorry, I'm not an astronomer. This question relates to the book "S." by Doug Dorst.

I understand that the celestial coordinates have a zero-point at the vernal equinox. (0h, 0m, 0s RA, 0⁰, 0", 0' Dec.)

I also understand that it's possible to map these coordinates to spherical, or geo-coordinates.

My question: Is there a standard mapping of celestial coordinates to the surface of the Earth? I bet that if there is, the vernal equinox would be pinned to 0⁰ N, 0⁰W. (The equator at GMT.)

For instance, Sagittarius, which is at 19h, 0m, 0s RZ, -25⁰, 0", 0', would map to 75⁰ W, 25⁰ S.

Is there such a correspondence, or did I just make that up?
 

phyzguy

Science Advisor
4,104
1,119
Of course, the Earth is spinning, so any correspondence can only occur at an instant in time. But yes, if you convert RA into degrees then RA corresponds to longitude, and declination corresponds to latitude. This is basically where the celestial coordinates come from. You can think of them as taking the Earth longitude and latitude lines and projecting them onto the plane of the sky.
 
Of course, the Earth is spinning, so any correspondence can only occur at an instant in time. But yes, if you convert RA into degrees then RA corresponds to longitude, and declination corresponds to latitude. This is basically where the celestial coordinates come from. You can think of them as taking the Earth longitude and latitude lines and projecting them onto the plane of the sky.
I understand that the Earth is rotating. I'm asking if there's a standard, fixed mapping of celestial coordinates to the surface of the Earth. Say, 0⁰ N, 0⁰ W would correspond to the vernal equinox. So that any given constellation always corresponds to a location on Earth's surface.

Has this already been done?
 

phyzguy

Science Advisor
4,104
1,119
Oh, OK. Thanks. Is there a name for this map? A Website I can go to and see the constellations mapped onto Earth?
 

berkeman

Mentor
54,781
5,037

phyzguy

Science Advisor
4,104
1,119
Well, you could try overlaying these two. I think they are both Mollweide projections centered on (0,0)

Mollweide_Earth.png
Mollweide_Celestial.png
 

Attachments

anorlunda

Mentor
Insights Author
Gold Member
6,343
3,515
There are also planetarium type programs that allow you to set your lat/lon to any value the time/date to any value and see what the sky looks like, including constellations. I use a free one called stellarium.
 

Want to reply to this thread?

"Is there a standard mapping of celestial coordinates to geo-coordinates" You must log in or register to reply here.

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top