Flat field issues solved

I am still in the early stages of getting used to the new set up. With the old system I attatched the field flattener and DSLR and the correct ccd to lens distance was achieved instantly giving full flat frames. The same applied to the FLT110 and the DSLR good round stars to the edge of the field but with the Starlight express camera elongation of the edge of frame stars was noticable. I downloaded CCD inspector to examine the field.

As you can see a clear problem. I didnt have any m48 spacers, thankfully Andrew ( a fellow blogger and member of BAS) has lent me some. A few combinations later and 35mm worth of spacing has produced a much more pleasing result. Good focus and FWHM figures from centre to edge.

 

 This process was done late evening after returning from the observatory at Great Ellingham. I wanted to give it a test run on a subject until the rise of the comets. I ended with a nice result from 12 x 10 minute exposures on the enigmatic M42. A DDP stretch and saturation gave a good sharp result with lovely structure to the wisps of nebolosity. Guiding was sub pixel accurate.