Dilettante Photography: Retrospective

I've seen plenty of star trails that have a 360 circumference, wondering if anyone knows exactly how to do that?  I know there's a method of taking numerous shots at way less exposure time but not sure of the details....  This is a 20 minute exposure - star trails surrounding power lines. Nikon D3200 / 18mm / f/5.6 / 1204" / ISO 200 - UV filter used to cut some of the light pollution. Post processed in Adobe Lightroom 5.6.

Thanks for the invite Michael Mossiagin - I work at Pepsi in Winston Salem, NC and am an avid amateur that is also self taught like Yannis Niklitsiotis - Look forward to some great shares!  This is a shot I took of Pilot Mountain using f/1.8 50mm prime lens stepped down to f/9 edited with Lightroom 5.6.