This imaging session involved the use of the Altair 6nm dualband filters (Ha/OIII' SII/OIII), a StellaMira 66mm ED f/6 refractor with a field flattener, a ZWO AEF, a 2" Altair magnetic filter holder and data captured with AstroDMx Capture.
The equipment
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 Deneb which was used to focus the scope with a Bahtinov mask. The ZWO AEF, which was fitted with a dew heater strip to prevent failure due to the cold temperatures, was controlled by AstroDMx Capture via the INDI server.
Capturing flats through an Altair Quadband filter using a variable brightness illuminated tracing panel as the light source
The same protocol was used to image a selection of nebulae:
40 minutes worth of 5 minute exposures were captured of each nebula through each of the two Dualband filters, with the exception of NGC 7000 where 30 minutes worth of 5 minute exposures were captured through each filter. Calibration frames were captured at the end of the session.
The objects imaged in this session were NGC 7000, the North American nebula; Sh 2-240, the Spaghetti nebula; IC2177, the Seagull nebula, and NGC 2359, Thor's Helmet nebula.
AstroDMx Capture capturing data through the Ha/OIII dualband filter
AstroDMx Capture capturing data through the SII/OIII dualband filter
The data were calibrated, stacked and data from the two filters co-aligned in Deep Sky Stacker. The data were split into RGB channels in the Gimp 2.10, combining the Green and Blue channels as OIII and processed in the Gimp, Starnet++, Neat Image, PixInsight and Photoshop CS2. and, in the case of the Gendler palette, Siril.
Different palette renderings were produced:
SHO, the Hubble Palette
The Gendler Palette
HOS, the Canada, France, Hawaii telescope palette
OSH palette
HSO palette
Sh 2-240, the Spaghetti nebula in SHO, the Hubble palette
IC 2177, the Seagull nebula in SHO, the Hubble palette
NGC 2359, Thor's Helmet nebula in SHO
NGC 2359, Thor's Helmet nebula in Bicolour HaOO
The Altair 6nm dualband filters have again proved to be very effective at capturing Ha, SII and OIII data with just two filters and an OSC cooled 14 bit camera
