Hi! So it's been a while since I've done this and uh I also haven't slept well over the past few days so literally nothing is clicking. I have so many questions about this celestial sphere business. Please bear with me. It also doesn't help that our notes have like 5 different diagrams of the same thing. So the celestial sphere is infinite, it stretches out around the Earth. The zenith and Nadir tilt depending on the person's location, right? If you're right in the middle of the equatorial plane, would your zenith align with the celestial poles (which align with the earth's poles apparently)? What if you're not a the center of the plane, then what happens? Does the sphere shift? I don't understand. Or does it stay expanded along earth's poles and equator but now you have to account for the tilt of the zenith/nadir when describing the location of the stars? I dont get this at all - some images have the poles of the earth and poles of the celestial sphere aligned and some don't . I don't know how else to explain what I'm having trouble with,I'm sorry. EDIT: So I found this site http://www.astronomynotes.com/nakedeye/s4.htm Basically, the celestial sphere is the extension of Earth, however the part of the celestial sphere that the observer sees changes because of their horizon at their latitude and their zenith? or no ? All of those have the observer at the center again - my professor said that the zenith and nadir go through the center of the earth and through the person so ?