I am seeking help calculating the Right Ascension. What I would like to know specifically, is if the Right Ascension can be calculated knowing the Zodiacal Longitude or Celestial Longitude of a plant, body or star. For example, for a body at 11° Pisces 57', which is 341°57' of Celestial Longitude, how can I determine the Right Ascension? Other variables that I know are the Sidereal Time and the Local Sidereal Time. I also know the terrestrial geographic Latitude. Variables that I can calculate (which perhaps might be helpful) are the Declination (the Arcsine[Sine(Obliquity) * Sine(Celestial Longitude)]). I can also calculate the Ascensional Difference (the Arcsine[Tan(Declination) * Tan(Latitude)]). Would it be possible to calculate the Oblique Ascension based on any the variables I know? If I could do that, then I could use the Oblique Ascension and Ascensional Difference to find Right Ascension. I am familiar with: Hour Angle = Local Sidereal Time - Right Ascension. However, I don't really understand what the Hour Angle is, other than I have seen it repeatedly defined as "the amount of time since an object has crossed the meridian." Which meridian? The location of the observer, or is the meridian a fixed point? Anyway, it appears that if the Right Ascension is 0° then the Hour Angle = Local Sidereal Time. For shats and gaggles, I set up a spread sheet and using the Local Sidereal Time, just calculated the Hour Angle using the Right Ascension in 15° increments to 360°. What I saw was the Hour Angle decreasing as the Right Ascension increases, but I don't understand the relationship between the two. Does the Hour Angle equate to Oblique Ascension or Celestial Longitude? Am I not approaching this right? Am I missing something here? Thanks in advance for anyone's help.