Abstract: A concentrating solar collector heat collecting element insulating shield has an elongated hemi-cylindrical body having an internal diameter approximately equivalent to (able to physically engage to) the outer diameter of the concentrating solar power (CSP) heat collecting element, either the evacuated outer tube, the fluid-carrying inner tube, or both. The device may have multiple layers of insulating/reflecting material, sheet metal, polymer, composite, may have flanges, fingers or other attachments to the CSP heat collecting element tube, or may be slightly greater than 180 degrees in arc so as to grip the CSP heat collecting element.