I tried to image NGC5189 and NGC6302 (Butterfly Nebula) over the past couple of years as I was moving up in my image systems. I thought it might worthwhile to share some results showing different resolving details. Scopes used were rebuilt Skywatcher 300F5 and 300F4, Skywatcher carbon Quattro 250F4, and GSO RC10. Cameras were ASI1600mm, 294mm, and 2600MM, using 3nm Antlia filters and Astronomik 6nm Ha, 6nm Oiii, 12nm Sii. Some of the data last year were plagued with mount and scope issues which resulted in guiding RMS errors of around 1 arcsec (total). This year's data were mostly with guiding errors of around 0.5 total (0.2-0.4 for both RA and DEC). Mount was CEM60, setup in my backyard of B8 sky in Sydney. In general I found that 300F5 with ASI2600mm was consistently giving me more details.
NGC5189 was a nebula with interesting patterns. Latest image in the past weeks was done in 10 min subs, 47x Ha, and 59x Oiii, totalling some 18 hours. I did some Sii but it was rather week and didn't give much colour improvements so I stayed with HOO. I did this target with 5min subs using ASI294 just to see if how it would come up since pixel scales with the 1500mm focal length of 300F5 for ASI2600 and 294 were 0.52 and 0.65 arcsec/pixel, respectively, which would both be higher than presumed average seeing conditions of Sydney skies. As the ASI2600 was bolted to filter wheel with 3nm filters I had to use another filter wheel with 6nm Ha and Oiii and 12nm Sii for ASI 294. I imaged this last year when my mount became worn which was fixed later. There was a structure weakness for focusing unit on my self-built Truss 300F5 which I only identified most recently. So last year's results using 300F5 was smeared by high guiding errors of around 1 arcsec due to both mount and scope issues. GSC RC10 result was also done last year with mount problems (RMS 1.0), and a T67 0.67x reducer was used for RC10.
The Butterfly nebula NGC6302 was done in similar ways this and last year. Best results were with 300F5 in 5min Ha, Oiii, and Sii subs of 154, 60, and 55, respectively, using 3nm filters, totalling 23 hours. I took about 20 hours of Ha (239x) but about half were ruined due to either loss of tightness mounting the camera and/or bad seeing, or an instant causing failure in median flip resulting RA system damages which needed re-adjustment. I was doing automated run using ASIair mini. So stars on the images were slightly oblong despite removing about half of data. I'm also including shots with ASI294 and ASI1600mm on Skywatcher Quattro 10 (250 f4 carbon) here. The ASI1600 image was done last year or year before when guiding was ok. I did this target last year using both 300F5 and 300F4 as well, but as the mount was faulty I couldn't get any better results even if I put all data together.
