The Rosette and Californian nebulae

This image of NGC2244, the Rosette nebula was taken using a blue filter combined with two narrow band filters O111 and H Alpha. The image here matches the focal length of the 4 inch refractor perfecty with a focal length of 642 mm. An exposure time of forty minutes was made using a blue filter and was combinded with 60 minute exposures using Olll and H-alpha narrowband filters:

This image of the California nebula is a mosaic of four images stitched together using Paint Shop Pro software.The data were collected on two seperate evenings, the H Alpha luminance data on one evening and the colour data on another. The sky was moonless and very clear with stars visible down to magnitude five which is good for city standards. The four luminance exposures were taken using 10 minute sub frames combinded with matching dark frames, a total exposure time of 90 minutes for each mosaic segment. On the second evening the sky conditions were very good but stars were only visible domn to magnitude 4.5. The exposure times were thirty minutes for each filter using 5 minute sub frames using the camera in x2 bin mode without including the dark frames. This image has a total exposure time of 12 hours: