There is a geocentric correction to planes parallel to the equator and others tangential to a sphere position and others tangential to oblate spheroid position (to account for the earth not being a sphere).

I understand that there are several ways to define azimuth and altitude depending upon the coordinate system. But what is geometric position? How is it compared to geocentric? I am using stellarium 0.12.5 because my graphics card cannot cope with the new open gl in 0.13īut what is geometric position for the moon? Does it mean topocentric? The difference between apparent and geometric does appear to be atmospheric refraction, because the azimuth remains unchanged and the moon becomes dostorted in shape with apparent. I am having trouble with the meaning of apparent and geometric and geocentric and topocentric and also parallax with regard to moon position in stellarium. Sunrise and sunset are defined with the center of the solar disc touching the I use 35♂4´´ as the value of refraction at horizon, and also I supposed that Me: geometric sunset at 19:48:16 apparent sunset at 19:53:01Ĭlearly, there is a big difference regarding times of APPARENT sunset (indeed,ĬalSky is quite closed to my calculation, more much that Stellarium). Stellarium: geometric sunset at 19:48:14 apparent sunset at 19:51:24

Geographic location: 43✢2♁6´N 8✢3♂4´ W altitude over the sea level = 0 There is a big difference between the APPARENT ones (setting the apparent The GEOMETRIC times in Stellarium (setting the geometric altitude to 0). I still find a very closedĪgreement between my GEOMETRIC calculated times (for sunrise and sunset) and However, I moved recently to version 0.11.0. Then, I guess that altitude was always corrected for refraction in these Sunset times and the times showed by Stellarium setting the altitude of Sun =Ġ. When I did myĬalculations (through a own made spreadsheet), I found practically noĭifference (a couple of seconds, at most) between my APPARENT sunrise and

One, but with no mention about which type of altitude was. In older versions of Stellarium (up to 0.8.0, until I know), there was noĭistinction between apparent and geometric altitude. OK, but then there is something I don´t catch.

Define stellarium