There are two very low cost smart scopes that use the same form-factor, similar optics and the same sensor. These are the ZWO Seestar S30 and the Dwarflabs Dwarf mini.
Both have 30mm objectives and focal Lengths of 150 mm at f/5. The both use the Sony IMX662 (1920x1080) sensor. The Seestar S30 presents the image in portrait format whereas the Dwarf mini presents the image in landscape format. Both scopes are primarily intended for deep sky imaging, but both are capable of imaging the Moon and the Sun (using the provided solar filters). The solar (and lunar) images produced are rather small, but because at this focal length, the image is under-sampled. During stacking, a 1.5 x drizzle can be beneficial, and produce a more useful sized stacked image.
The philosophy of solar and lunar imaging with the Seestar S30 and the Dwarf mini are completely different. The Seestar S30 captures an 8 bit RAW AVI which can be several thousand frames and the Dwarf mini captures 16 bit RAW FITS files. The Dwarf mini defaults to capturing a mere 20 frames, although this can be increased arbitrarily, but because it is a slower process, inevitably far fewer frames will be captured. The Seestar approach is more suited to stochastic or so-called 'lucky imaging' that enables the selection of the best moments of seeing during frame selection and stacking.
There are a number of ways of approaching the analysis and stacking of the FITS files produced by the Dwarf mini. However, we believe that the following is the most economical and suitable method.
We did the data capture on a very poor day through gaps in the clouds. We captured just two sets of 20 FITS files with a number of them being affected to some extent by clouds. (on a better day, larger numbers of frames could be captured to the benefit of the quality of the final image).
The gain was set to zero and the shutter speed to 1/800s which produced a correctly exposed preview on the tablet screen. (With better transparency, faster shutter speeds may be more suitable).
The 40 FITS images that were captured were placed in a single folder (directory) and Autostakkert! 4.0.13 was used to debayer and stack the best 50% of the files.
The problem is that Autostakkert! is a Windows program that expects the origin of an image to be top left, whereas the FITS standard places the origin at the bottom left by default, (although it is specifiable) and the Dwarf mini places the origin at the bottom left. This means that although the bayer pattern of the Sony IMX662 is RGGB, Autostakket! will by default debayer the image incorrectly. To correct this the image needs to be effectively flipped vertically, which in Autostakkert! can be achieved by forcing GBRG as the bayer pattern.
The best 50% of the RAW FITS files being debayered and stacked in Autostakkert!
