Messier 17, also known as NGC 6618 or the "Swan Nebula", "Omega Nebula", "Horseshoe Nebula", "Lobster Nebula" or "Checkmark Nebula", is an emission nebula in the constellation of Sagittarius. This image comprises 10 x Ha, OIII and SII, all 300 seconds each with the 0.5m f/2.9 ASA Astrograph with FLI ML3200 camera at an altitude of 40 degrees over two nights, 29 May and13 June 2016.The fields of view of the images at the top and bottom are 34’ x 23’. The top image follows the HST convention, with cloours mapped as follows: SII-Ha-OIII mapped to RGB. The bottom imageshows the same frames presented using the CFHT convention, Ha-OIII-SII mapped to RGB.The field of view of both images are 34’ x 12’.
Hills Observatory: 1 January 2013 to 8 October 2018