Altazimutal grid not overlapping equatorial grid when located on poles
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Stellarium |
Fix Released
|
Medium
|
Shantanu Agarwal |
Bug Description
Hi.
Here is another question for you:
I have heard that at the onset of Spring Equinox, somewhere along the Equator, the Sun will be directly overhead of an observer.
Directly overhead implies the object is at 90 degree elevation or zero degrees zenith.
Stellarium interface provides an option to view Azimuthal Grids which meet at a point in the sky which looks like it could be the Zenith. However, the Ecliptic doesn't look like it ever crosses that point. If it is true the at the moment of Equinox the Sun will be directly overhead shouldn't the Ecliptic cross the zenith at the same moment in time on both the Equinoxes, Spring and Automnal?
To test this I created a North Pole location, N 90 degrees and E 0 degrees. Looking directly overhead it looks like Azimuthal Grid and Equilateral grids are not co-centric as I thought they should be. They are slightly off. I am sure there is a good reason for it.
Thanks for your help and input.
Farzad
Related branches
Changed in stellarium: | |
status: | New → Confirmed |
importance: | Undecided → Medium |
milestone: | none → 1.0.0 |
Changed in stellarium: | |
status: | Fix Committed → Fix Released |
Hi
The difference between the directions of the poles of the Alt-Az and Equatorial system is about half a degree. This is really quite a difference! There is no difference between the two systems at the equator.
For me, teaching childern about coordinate systems, this is a problem....
Cheers
Massimo