M42 in Hα and OIII; 13th March 2007

This are my first pictures taken using new (commercial) H-α and Oxygen III filters.  Both are Astronomik filters with band-widths of 13 nm;  The H-α is centred at 656 nm, the OIII is centred at 501 nm.  Both can be used to enhance emission nebulae which emit well at both these wavelengths and the filters block the majority of light pollution (sodium and mercury emissions mainly).
Both the pictures were taken using my Skywatcher ST80 refractor and Atik ATK-1 HS raw-modified monochrome camera. Three different exposures, 10, 5, and 2 seconds were combined and all processing was identical for the two pictures.
Moving your mouse over either of the two top images will display the other one.   At the bottom of the page I show a combined, and enhanced, image .

	This is picture in H-α light.  I thought I had captured more of the outer nebulosity than appears here.  I have artificially coloured the original monochrome image.
	This is picture in OIII light.  I am not sure if the extra detail, compared to the image above, is real or results from, maybe, better focus or different resolutions of my telescope at the two wavelengths.  Again I have artificially coloured the original monochrome image.
	Finally I have combined the two coloured images to yield a composite of both.  For this image only I have increase the gamma to 1.4 and stretched the histogram 0-180 in order to try to show the outer nebulosity which is there.  Also M43 is clearly visible in this image.

Date and Time	13th March 2007 19:28 to 20:18 UT
Camera	Atik ATK-1 HS raw modified
Telescope	Skywatcher ST80 refractor with Astronomik H-α and OIII filters
Capture	K3CCDTools. 2, 5, 10 sec exposures, 90% gain, high gamma, ~60 frames each
Processing	K3CCDTools. Each avi stacked and saved in png16 format. Registax. Stacking of the separate images, gamma 1.4, histogram 0-180.

			Home      Back to DSOs