Telescope Specification

• Model: Planewave CDK24
• Aperture: 610 mm (24 inches)
• Focal Length: 3962 mm
• F-ratio: 6.5
• Mount: Mathis MI-1000/1250 with absolute encoders

CMOS Camera Specification

• Model: QHY 600M Pro
• Pixel Size: 3.76s μm
• Pixel Array: 9576 x 6382 pixels
• Pixel Resolution: 0.39 arcsec/pixel in BIN2
• Field of View: 31 x 20.7 arcmin

RCW 75 (also known as Gum 48a) is a seldom imaged emission nebula (a large H II region) in the constellation Centaurus. It is located in the southern part of the constellation midway between the bright stars Hadar and Acrux. The distance to RCW 75 is estimated to be not less than 6520 light years; This complex appears physically associated with the open cluster Stock 16. The nebulosity would also associated with the reflection nebula vdBH 60.

The RCW Catalogue (from Rodgers, Campbell & Whiteoak) is an astronomical catalogue of Hα-emission regions in the southern Milky Way, described in (Rodgers et al. 1960). It contains 182 objects, including many of the earlier Gum catalogue (84 items) objects. The later Caldwell catalogue included some objects from the RCW catalogue. There is also some overlap with the Sharpless catalogue-2 (312 items), although that primarily covered the northern hemisphere, whereas RCW and Gum primarily covered the southern hemisphere. The RCW catalogue was compiled by Alexander William Rodgers, Colin T. Campbell and John Bartlett Whiteoak. They catalogued southern nebulae while working under Bart Bok at the Mount Stromlo Observatory in Australia in the 1960s.