[glenc (Glen)]

Lacaille (1751-2), James Dunlop (1826) and John Herschel (1834-8) discovered most of the NGC clusters, nebulae and galaxies in the far southern sky. Their telescopes (0.5", 9" and 18.5" respectively) were set up to sweep along the meridian. Each north-south sweep was about 3 degrees long in declination. When they found an object they recorded the time when it transited and its declination using a graduated circle. To improve their accuracy they included stars with known RA in their sweeps. When Dunlop made the first maps of the LMC and SMC he stopped sweeping and just let the cloud drift by while he recorded the time and the distance north or south from the centre of his eyepiece field for each new object as it drifted by.