A Stella Mira 66 ED APO refractor with a field flattener and an Altair magnetic 2" filter holder with an Altair Quadband filter was mounted on a Celestron AVX mount. An SVBONY SV405CC 14 bit, cooled CMOS camera was used as a native implemented camera.
Click on an image to get a closer view
The Altair Quadband OSC narrowband filter transmits two spectral bands:
FWHM spans 477.5nm - 512.5nm at the blue-green end of the visible spectrum and FWHM spans 642.5nm - 677.5nm at the red end of the spectrum.
The first band contains the emission lines of H-beta at 486.1nm and OIII at 495.9nm and 500.7nm and is centred on 495nm.
The second band contains the emission lines of H-alpha at 656.3nm and SII at 672.4nm and is centred on 660nm.
The Filter is called ‘Quadband’ because it contains the emission lines of these four elements.
Each of the two transmission bands has a FWHM of 35nm and the rest of the visible spectrum is essentially blocked. The filter’s two spectral bands are quite wide and it is an effective light pollution filter.
Capturing flat fields with an illuminated tracing screen
PHD2 auto pulse-guiding was done by a separate Linux computer also running indoors. An SVBONY SV165 guide scope with a QHY-5II-M guide camera was used for auto-guiding.
AstroDMx Capture captured 1 hour 15 minutes worth of 5 minute exposures of M31 the Andromeda galaxy
The data were calibrated an stacked in Deep Sky Stacker, processed in the Gimp and the Starnet++ Gimp plugin, Neat Image and Photoscape X Pro.
M31 the Andromeda galaxy
