[glenc (Glen)]

Scotsman James Dunlop arrived in NSW in Nov 1821. He spent nearly 4 years making a catalogue of 7385 stars for Governor Sir Thomas Brisbane. Charles Rumker helped him do this for a while, but left after clashing with Brisbane. Brisbane returned to Scotland in December 1825 and Dunlop finished the star catalogue in February 1826.

In April 1826 Dunlop moved from the observatory to a friends place in Marsden St Parramatta and started making a catalogue of star clusters, nebulae and galaxies with a homemade 9” (23 cm) aperture speculum reflector that was 9’ (274 cm) long. The telescope was set up at the back of 91 Marsden St and pointed south. Dunlop swept up and down across the night sky and recorded the sidereal time, angle from the south celestial pole and a description, every time he found a cluster, nebula or galaxy. He had to climb a ladder for some objects and used a faint lantern to record his observations. In just 7 months he found 278 new objects. This included 23 new globular clusters, not counting the GC in the Magellan Clouds.

Dunlop (1826), Sir John Herschel (1831) and E E Barnard (1882) all claimed to have discovered NGC 5824. It is obvious from Dunlop’s description that he saw it first. Dunlop (D611) observed it 4 times and described it as "A very singular body resembling a star with a burr. The light is equal to that of a star of the 7th and 8th magnitude, and the diameter is not sensibly larger, with various magnifying powers. This has the appearance of a bright nucleus, surrounded by a strong brush of light; and the nebulosity surrounding the bright point has not that softness which nebulae in general possess. I consider this different from nebulae in general."

I (Glen) have seen all of these 23 Dunlop globular clusters in the last 2 nights. The attached table gives their concentration (I to XII), the 1826 date when they were found (M, D), their visual magnitude and their approximate diameter in arc-mins.

NGC 6101 is one of the faintest Dunlop GC, this image of it is from the HST.