A William Optics apochromatic refractor was mounted on a Celestron AVX EQ, GOTO mount. An Atik 314L monochrome 16-bit CCD camera fitted with a narrowband H-alpha filter was placed at the focus of the telescope and AstroDMx Capture for Linux was used to capture 16-bit FITS files. (AstroDMx Capture for Windows or macOS could have been used as they are essentially identical in operation).
The equipment used
40 x 60s exposures of the Horsehead and Flame nebulae were captured with matching dark frames. The images were registered and stacked in Deep Sky Stacker and the autosaved 32-bit file was post processed in the Gimp 2.10, Afinity Photo and Neat Image.
Screenshot of AstroDMx Capture for Linux capturing data on the Horsehead and Flame nebulae.
Various Preview and Software controls were used to visualise the 16-bit image. It should be noted that whilst it is possible to make adjustments to these controls so that the preview is more pleasing to view, the purpose of these controls is to make the preview visible so that the image can be composed and checked during capture. The preview controls have no effect on the saved data. The same is true of the Software controls.
Example of the Preview and Software controls
The Horsehead and Flame nebulae Stack of 40 x 60s exposures
Screenshot of AstroDMx Capture saving Data on the Rosette nebula
Clouds prevented more than 16 x 60s exposures of the Rosette nebula. Nevertheless, a pleasing image was obtained when the 32-bit autosaved file was post processed in the Gimp, Affinity Photo and Neat image.
The Rosette nebula stack of 16 x 60s exposures
Despite the fact that there was a gibbous Moon in the sky close to Orion, the H-alpha filter allowed the moonlight to be filtered out revealing the H-alpha content of the nebulae.
Modifications to the 16-bit Preview controls were being tested and following some more refinements, will shortly be included in a new release of AstroDMx Capture for Windows, macOS and Linux (including AstroDMx Capture for the Raspberry Pi).
