Please Help. Radio Spectroscopy -> Finding the doppler shift in a graph

PhysicsHelp12

I've been trying this for 3 hours and I'm getting nowhere. These are the graphs I made for Hydrogen Intensity vs Frequency for a radio telescope that transits the sun and galactic arms of the galaxy.


http://img220.imageshack.us/img220/5...lpgraphia6.jpg


http://img139.imageshack.us/img139/8038/graph1nr8.jpg



http://img139.imageshack.us/img139/4486/graph2pp2.jpg

I need to find the rotation speed of the earth and the galactic arms. So I know I need to measure the doppler shift ...but my problem is, I don't know which spikes correspond to what. What spikes are from the sun or local space and which are from the galactic arms.


Anybody please help?

PhysicsHelp12

Nevermind this I figured most of it out ---


but can someone please help me determine which spike comes from the sun?

I know it's either the really thin intense one that's on all 3 ...but that looks more like a stray point to me ....or it's the other really large one that's thicker