# Parallax - Our vantage point of objects in the universe changes relative to the sun - Place it against the back stars - A nearby star will result in a certain parallax motion ![](attachments/Parallax-attachment.png#invert) - A closer star will have greater parallax motion ![](attachments/Parallax-attachment-1.png#invert) - An angle of one arc second means a distance of one parsec and we can measure to 1 milli arcsecond (about 1kparesec)![](attachments/Parallax-attachment-2.png#invert) - Useful for local objects - The celestial sphere is the background stars that don't appear to move # References 1. # Footnotes