The equipment comprised a Stella Mira 66 ED APO refractor with a field flattener and Altair magnetic 2" filter holder with Altair 6nm dualband filters (Ha/OIII' SII/OIII); a ZWO EAF and an Altair Hypercam 533C 14 bit OSC CMOS camera.
The data were capture with AstroDMx Capture for Windows. The scope was mounted on an AVX GOTO mount which was controlled by AstroDMx Capture via an INDI server running on the imaging computer indoors.
The mount was placed on marks on the ground which quickly gives quite a good polar alignment if care is taken with the placement of the tripod feet.
An SVBONY SV165 guide scope with a natively connected QHY-5II-M guide camera was used for PHD2 multistar pulse auto-guiding via the INDI server. The auto-guiding was controlled by a separate Linux laptop indoors.
AstroDMx Capture sent the scope/mount to the star Arcturus which was used to focus the scope with a Bahtinov mask. The ZWO AEF was controlled by AstroDMx Capture via the INDI server.
The Altair Hypercam 533C OSC camera was chosen because like all Touptek derived cameras, it can produce true RAW images. That is, there are no destructive controls such as gamma and white balance applied before the data are saved. A result of this is that the RAW data have a green hue when viewed. This is perfectly normal because in the Bayer matrix of colour filters over the pixels, half of the filters are green whilst a quarter are red and a quarter are blue.
Although this can be distracting and even disappointing when previewing the data, AstroDMx Capture's non destructive DMx white balance control (which does not affect the save data) removes the green hue and correctly white balances the preview. The true RAW nature of the data means that no information has been lost during the capture process and everything has to be done during processing and post processing. An advantage of capturing RAW data is that the file size is only a third of the size of fully debayered RGB data files. Some capture software can only capture RAW data but AstroDMx Capture gives the option of saving fully debayered, 16 bit data, and the user can choose the quality of the debayering algorithm used.
Screenshot of AstroDMx Capture capturing RAW fits files of M16, the Eagle nebula but the non-destructive DMx white balance is turned on to correctly white balance the preview.
Capturing with the Ha/OIII dualband filter
Capturing with the SII/OIII dualband filter
Calibration frames were also captured
The two sets of data were debayered, cosmetically corrected, stacked and partly processed in PixInsight and further processed in GraXpert, Gimp 2.10 and Starnet++. The colour channels were decomposed to produce Ha and OIII data from one filter with SII and OIII from the other filter.
The starless OIII data were combined from both filters and composed back into various palette renderings in the Gimp. The SHO data were further selective colour processed in Photoshop CS2 and all of the palettes were post processed in the Gimp.
Two bicolour palette renderings of the Eagle nebula were made:
HOO palette
SOO palette
SHO Hubble palette
HOS, Canada, France, Hawaii telescope palette
Solar imaging
Using the same camera/scope setup with a Baader OD 3.8 solar filter and a UV/IR cut filter in the magnetic filter holder. AstroDMx Capture for Windows was used to send the scope to the Sun and to capture a 1200-frame RAW AVI of the whole solar disk.
Screenshot of AstroDMx Capture capturing RAW, 8-bit solar data
Notice the green hue of the RAW data.
Screenshot of AstroDMx Capture capturing RAW, 8-bit data but with the DMx white balance turned on
The data were debayered and the best 85% of frames stacked in Autostakkert!4, wavelet processed in waveSharp and post processed in the Gimp 2.10.\
