We present a low-cost Raspberry Pi-based star sensor StarberrySense using commercial-off-the-shelf components, developed and built for applications in small satellites and CubeSat-based missions. A star sensor is one of the essential instruments on board a satellite for attitude determination. However, most commercially available star sensors are expensive and too bulky for use in small satellite missions. StarberrySense is a configurable system—it can operate as an imaging camera, a centroiding camera, or a star sensor. We describe the algorithms implemented in the sensor, its assembly, and its calibration. This payload was selected by a recent announcement of an opportunity call for payloads to fly on the PS4-Orbital Platform by the Indian Space Research Organization.

Context. NGC 40 is a planetary nebula with diffuse X-ray emission, suggesting an interaction of the high-speed wind from WC8 central star (CS) with the nebula. It shows strong C IV 1550 Å emission that cannot be explained by thermal processes alone. We present here the first map of this nebula in C IV emission using broad band filters on the Ultra-Violet Imaging Telescope (UVIT). Aim. We aim to map the hot C IV-emitting gas and its correspondence with soft X-ray (0.3–8 keV) emitting regions in order to study the shock interaction between the nebula and the ISM. We also aim to illustrate the potential of UVIT for nebular studies. Methods. We carry out a morphological study of images of the nebula obtained at an angular resolution of about 1.3″ in four UVIT filter bands that include C IV 1550 Å and [C II] 2326 Å lines as well as UV continuum. We also make comparisons with X-ray, optical, and IR images from the literature. Results. The [C II] 2326 Å images show the core of the nebula with two lobes on either side of CS similar to [N II]. The C IV emission in the core shows similar morphology and extent to that of diffuse X-ray emission concentrated in nebular condensations. A surprising UVIT discovery is the presence of a large faint far UV (FUV) halo in an FUV filter with λ_eff of 1608 Å. The UV halo is not present in any other UV filter. The FUV halo is most likely due to UV fluorescence emission from the Lyman bands of H₂ molecules. Unlike the optical and IR halo, the FUV halo trails predominantly towards the south-east side of the nebular core, opposite to the CS’s proper motion direction. Conclusions. Morphological similarity of C IV 1550 Å and X-ray emission in the core suggests that it results mostly from the interaction of strong CS wind with the nebula. The FUV halo in NGC 40 highlights the extensive existence of H₂ molecules in the regions even beyond the optical and IR halos. Thus UV studies are important to estimate the amount of H₂, which is probably the most dominant molecule and significant for mass-loss studies.

The high excitation planetary nebula, NGC 6302, has been imaged in two far-ultraviolet (FUV) filters, F169M (Sapphire; λ _eff : 1608 Å) and F172M (Silica; λ _eff : 1717 Å) and two near-UV (NUV) filters, N219M (B15; λ _eff : 2196 Å) and N279N (N2; λ _eff : 2792 Å) with the Ultra Violet Imaging Telescope (UVIT). The FUV F169M image shows faint emission lobes that extend to about 5 arcmin on either side of the central source. Faint orthogonal collimated jet-like structures are present on either side of the FUV lobes through the central source. These structures are not present in the two NUV filters or in the FUV F172M filter. Optical and infrared (IR) images of NGC 6302 show bright emission bipolar lobes in the east-west direction with a massive torus of molecular gas and dust seen as a dark lane in the north-south direction. The FUV lobes are much more extended and oriented at a position angle of 113°. They and the jet-like structures might be remnants of an earlier evolutionary phase, prior to the dramatic explosive event that triggered the Hubble type bipolar flows approximately 2200 years ago. The source of the FUV lobe and jet emission is not known, but is likely due to fluorescent emission from H ₂ molecules. The cause of the difference in orientation of optical and FUV lobes is not clear and, we speculate, could be related to two binary interactions.