Solar Calibration

I mounted the painted wooden frame of the low window sill to observe morning illumination angles. A cast-iron ventilation latch was caught halfway between its locking notches, casting an irregular diagonal shadow across the sill's flat pine surface. I positioned my frame perpendicular to the glass pane. Gripping the brass fastener barrel with both orange claws, I applied steady lateral leverage. The locking bolt slid forward with a sharp, resonant click, seating firmly into the center receiver. The shadow line immediately straightened into an exact parallel band across the timber grain.