On Tuesday, October 31, 2017 at 7:10:10 PM UTC, palsing wrote:
On Tuesday, October 31, 2017 at 12:02:46 AM UTC-7, Gerald Kelleher wrote:

RA/Dec is an extension of the 24 hour system...

This just wrong in many ways, the RA/DEC system that we use is based on an extension of the Earth's axis of rotation, hence the name equatorial coordinate system.

I am afraid not Paul for the reason presented many times, the Lat/Long system required the construction of a meridian line to accurately determine the moment when the observer and his location were midpoint to the circle of illumination at noon. All observers along that meridian,irrespective of season or hemisphere, experience noon at the same time so the application of the Equation of Time rendered natural noon into 24 hour clock noon . If the observer was on a ship at sea he could then determine his location to any other meridian and any location on the planet as time difference equates to geographic separation.

The RA/Dec framework is homocentric as two sticks positioned in any direction will give you the same result so don't fool yourself into equating celestial sphere rotation with daily rotation,at least not directly.



If we extend the Earth's axis outward into space, its intersection with the celestial sphere defines the north and south celestial poles; equidistant between them, and lying directly over the Earth's equator, is the celestial equator... I invite you to read this...

http://sbo.colorado.edu/SBO_OLD_SITE...ordinates.html


Celestial sphere ideology is always the same, it assigns relevance to circumpolar motion and models the motions of the Earth on the assertions even though they defy experience. They don't even do this anymore as they conjured up a new proposal that the Earth turned 360 degrees in 24 hours but back in the year 1820 as the website Martin Brown referenced. When you begin with an error, it follows you through the centuries and in this case it was a failure to recognize with some conditions -

One 24 hour weekday equates to one 360 degree rotation
One year does not equate to one orbital period

A year can have 365 days/rotations in it or 366 days/rotations in it because the timekeeping term 'year' is drawn from the calendar framework. There is no external observation for 365 1/4 days/rotations per orbital circuit as the default or parent observation was always 1461 days/rotations to 4 orbital circuits.



... although I already know that you are incapable of actually learning something and will only respond with some rude statement that makes no sense....


Stop with the slogans and stock phrases, this is not sci.relativity.




It is impossible to justify RA/Dec in dynamical terms because it loses cause and effect between the weekday and rotation...

Well, of course it does, since its purpose has nothing to do with the solar day, but rather with the sidereal day, 2 very different things...

Ultimately you are being left behind by the new crowd who really are looking for ways to cut the ties between the 24 hour weekday and daily rotation through the hallucination of 'leap seconds'. The Precession of the Equinox is a further refinement of the original references which created the calendar framework based on the first seasonal appearance of a star from behind the glare of the central Sun.