Abstract: The large-scale mass distributions of strong-lensing galaxies have long been assumed to be well-described by a singular ellipsoidal power-law density profile with external shear. However, the inflexibility of this model could lead to systematic errors in astrophysical parameters inferred with gravitational lensing observables. Here, we present observations with the Atacama Large (sub-)Millimetre Array (ALMA) of three strongly lensed dusty star-forming galaxies at $\simeq30$ mas angular resolution and investigate the sensitivity of these data to angular structure in the lensing galaxies. We jointly infer the lensing mass distribution and the full surface brightness of the lensed sources with multipole expansions of the power-law density profile up to fourth order using a technique developed for interferometric data. All three data sets strongly favour third and fourth-order multipole amplitudes of $\approx1$ percent of the convergence. While the infrared stellar isophotes and isodensity shapes agree for one lens system, for the other two the isophotes disagree to varying extents, suggesting contributions to the angular structure from dark matter intrinsic or extrinsic to the lensing galaxy.

Abstract: Abstract We present two new methods of processing data from backscattered electron signals in a scanning electron microscope to image grains and subgrains. The first combines data from multiple backscattered electron images acquired at different specimen geometries to (1) better reveal grain boundaries in recrystallized microstructures and (2) distinguish between recrystallized and unrecrystallized regions in partially recrystallized microstructures. The second utilizes spherical harmonic transform indexing of electron backscatter diffraction patterns to produce high angular resolution orientation data that enable the characterization of subgrains. Subgrains are produced during high-temperature plastic deformation and have boundary misorientation angles ranging from a few degrees down to a few hundredths of a degree. We also present an algorithm to automatically segment grains from combined backscattered electron image data or grains and subgrains from high angular resolution electron backscatter diffraction data. Together, these new techniques enable rapid measurements of individual grains and subgrains from large populations.

Abstract: Abstract We present a statistical characterization of circumstellar disk orientations toward 12 protostellar multiple systems in the Perseus molecular cloud using the Atacama Large Millimeter/submillimeter Array at Band 6 (1.3 mm) with a resolution of ∼25 mas (∼8 au). This exquisite resolution enabled us to resolve the compact inner-disk structures surrounding the components of each multiple system and to determine the projected 3D orientation of the disks (position angle and inclination) to high precision. We performed a statistical analysis on the relative alignment of disk pairs to determine whether the disks are preferentially aligned or randomly distributed. We considered three subsamples of the observations selected by the companion separations a < 100 au, a > 500 au, and a < 10,000 au. We found for the compact (<100 au) subsample, the distribution of orientation angles is best described by an underlying distribution of preferentially aligned sources (within 30°) but does not rule out distributions with 40% misaligned sources. The wide companion (>500 au) subsample appears to be consistent with a distribution of 40%–80% preferentially aligned sources. Similarly, the full sample of systems with companions ( a < 10,000 au) is most consistent with a fractional ratio of at most 80% preferentially aligned sources and rules out purely randomly aligned distributions. Thus, our results imply the compact sources (<100 au) and the wide companions (>500 au) are statistically different.

Abstract: We present the development of a large-volume, increased field-of-view Time Projection Chamber (TPC) for x-ray polarimetry, utilizing a triple-GEM detector with optical readout. Initially optimized for directional Dark Matter searches, this system employs a scientific CMOS (sCMOS) camera and a PMT to detect secondary scintillation light produced during the TPC amplification stage. A prototype TPC with a cylindrical active volume of radius 3.7 cm and height 5 cm was tested at the INAF-IAPS calibration facility in Rome, Tor Vergata to establish the instrument's sensitivity to low-energy electron direction. Complete reconstruction of electrons in the 10-60 keV range with angular resolution down to 15° was measured, resulting in inferred modulation factors up to 0.9. We will present the initial results from our test campaign, which confirm effective photoelectron tracking in the tens of keV range with a strong modulation factor. This innovative approach could extend x-ray polarimetry sensitivity to higher energies and possibly enable the observation of rapid transient phenomena, such as Gamma Ray Bursts (GRBs) and solar flares, thus contributing significantly to x-ray astronomy.

Abstract: Diffusion-weighted imaging (DWI) is a type of Magnetic Resonance Imaging (MRI) technique sensitised to the diffusivity of water molecules, offering the capability to inspect tissue microstructures and is the only in-vivo method to reconstruct white matter fiber tracts non-invasively. The DWI signal can be analysed with the diffusion tensor imaging (DTI) model to estimate the directionality of water diffusion within voxels. Several scalar metrics, including axial diffusivity (AD), mean diffusivity (MD), radial diffusivity (RD), and fractional anisotropy (FA), can be further derived from DTI to quantitatively summarise the microstructural integrity of brain tissue. These scalar metrics have played an important role in understanding the organisation and health of brain tissue at a microscopic level in clinical studies. However, reliable DTI metrics rely on DWI acquisitions with high gradient directions, which often go beyond the commonly used clinical protocols. To enhance the utility of clinically acquired DWI and save scanning time for robust DTI analysis, this work proposes DirGeo-DTI, a deep learning-based method to estimate reliable DTI metrics even from a set of DWIs acquired with the minimum theoretical number (6) of gradient directions. DirGeo-DTI leverages directional encoding and geometric constraints to facilitate the training process. Two public DWI datasets were used for evaluation, demonstrating the effectiveness of the proposed method. Extensive experimental results show that the proposed method achieves the best performance compared to existing DTI enhancement methods and potentially reveals further clinical insights with routine clinical DWI scans.

Abstract: Nulling interferometry has emerged as a promising technique for imaging exoplanets, effectively overcoming the challenges of contrast and angular resolution faced by ground-based telescopes. The Guided Light Interferometric Nulling Technology (GLINT) instrument at the Subaru telescope in Hawaii utilises this technique, where a new integrated optics beam combiner will be deployed, capable of simultaneously performing nulling interferometry and fringe tracking. Fabricated using the femtosecond laser direct write technique in boro-aluminosilicate glass, the beam combiner integrates three single-mode waveguides as inputs to form 3 interferometric baselines. The design, fabrication and laboratory characterisation of the new beam combiner will be presented. The beam combiner comprises of 3D-printed micro lenses, a chrome mask, Y-Junctions, achromatic phase shifters and tricouplers to produce for each baseline an achromatically-nulled and two phase-sensitive bright outputs. This results in a total of 12 outputs that are directed onto a CRED2 camera.

Abstract: High angular resolution diffusion-weighted imaging (HARDI) protocols are strategies used to growth the number of facts amassed about tissue microstructure in diffusion imaging. Current studies have sought to apprehend the validity of HARDI methods and their ability to reconstruct the underlying tissue systems accurately. The evaluation of HARDI reliability is accomplished thru 3 major classes: voxel-wise checks of methods, simulations to evaluate protocol efficiency, and human brain tract reconstruction. outcomes from these studies have tested that HARDI may additionally offer progressed visualization of mind microstructure and might higher differentiate between individual white count tracts and distinctive tissue kinds than conventional diffusion imaging. However, due to the complexity of HARDI protocols, further validation is essential to ensure accuracy and discover the strengths and weaknesses of the strategies.

Abstract: ESO's Very Large Telescope Interferometer has a history of record-breaking discoveries in astrophysics and significant advances in instrumentation. The next leap forward is its new visitor instrument, called Asgard. It comprises four natively collaborating instruments: HEIMDALLR, an instrument performing both fringe tracking and stellar interferometry simultaneously with the same optics, operating in the K band; Baldr, a Strehl optimizer in the H band; BIFROST, a spectroscopic combiner to study the formation processes and properties of stellar and planetary systems in the Y-J-H bands; and NOTT, a nulling interferometer dedicated to imaging nearby young planetary systems in the L band. The suite is in its integration phase in Europe and should be shipped to Paranal in 2025. In this article, we present details of the alignment and calibration unit, the observing modes, the integration plan, the software architecture, and the roadmap to completion of the project.

Abstract: We present a project aiming at evaluating a novel hybrid imaging/timing detector concept comprising a photocathode, a chevron-stack micro-channel plate, and a TimePix3 readout ASIC for the detection of visible photons with high time resolution and good quantum efficiency and spatial resolution. Due to these attributes, this detector holds significant promise for time-domain astronomy. The evaluation and data collection for this project will primarily occur at the OARPAF observatory (80cm primary mirror) with the objective of pioneering this technology in the astronomical domain and gathering essential information to advance toward developing an instrument based on this technology for the Telescopio Nazionale Galileo at a later stage.

Abstract: The European Southern Observatory’s Extremely Large Telescope (ESO’s ELT) stands as the cornerstone of ESO’s ambitious vision to build a new facility capable of providing a paradigm shift in our understanding of the cosmos. ESO’s ELT is swiftly advancing towards completion, having surpassed, in June 2023, the 50% completion milestone. Possessing unparalleled sensitivity and angular resolution thanks to its 39-metre main mirror, ESO’s ELT holds the potential to revolutionise our perspective on the Universe, from the exploration of exoplanets to the detailed study of stellar populations, and from unravelling the mysteries of galaxy evolution to probing fundamental physics and cosmology.

Abstract: A meta-lens array-based Shack-Hartmann wavefront sensor has been developed to break the limits imposed by the size and curvature of traditional micro-lenses, which significantly improves both sampling density and angular resolution of phase measurement. Metasurface advances the field of optical phase measurement to smaller-scale complex wavefront characterization. A meta-lens array-based Shack-Hartmann wavefront sensor enhances phase measurement by increasing sampling density and angular resolution, advancing optical wavefront sensing with metasurface technology.

Abstract: Whole slide imaging provides a wide field-of-view (FOV) across cross-sections of biopsy or surgery samples, significantly facilitating pathological analysis and clinical diagnosis. Such high-quality images that enable detailed visualization of cellular and tissue structures are essential for effective patient care and treatment planning. To obtain such high-quality images for pathology applications, there is a need for scanners with high spatial bandwidth products, free from aberrations, and without the requirement for z-scanning. Here we report a whole slide imaging system based on angular ptychographic imaging with a closed-form solution (WSI-APIC), which offers efficient, tens-of-gigapixels, large-FOV, aberration-free imaging. WSI-APIC utilizes oblique incoherent illumination for initial high-level segmentation, thereby bypassing unnecessary scanning of the background regions and enhancing image acquisition efficiency. A GPU-accelerated APIC algorithm analytically reconstructs phase images with effective digital aberration corrections and improved optical resolutions. Moreover, an auto-stitching technique based on scale-invariant feature transform ensures the seamless concatenation of whole slide phase images. In our experiment, WSI-APIC achieved an optical resolution of 772 nm using a 10x/0.25 NA objective lens and captures 80-gigapixel aberration-free phase images for a standard 76.2 mm x 25.4 mm microscopic slide.

Abstract: The Single Aperture Large Telescope for Universe Studies (SALTUS) probe mission will provide a powerful far-infrared (far-IR) pointed space observatory to explore our cosmic origins and the possibility of life elsewhere. The observatory employs an innovative deployable 14-m aperture, with a sunshield that will radiatively cool the off-axis primary to <45 K. This cooled primary reflector works in tandem with cryogenic coherent and incoherent instruments that span 34- to 660-μm far-IR range at both high and moderate spectral resolutions. The mission architecture, using proven Northrop Grumman designs, provides visibility to the entire sky every 6 months with ∼35% of the sky observable at any one time. SALTUS's spectral range is unavailable to any existing ground or current space observatory. SALTUS will have 16× the collecting area and 4× the angular resolution of Herschel and is designed for a lifetime of ≥5 years. The SALTUS science team has proposed a Guaranteed Time Observations program to demonstrate the observatory's capabilities and, at the same time, address high-priority questions from the Decadal survey that align with NASA's Astrophysics Roadmap. With a large aperture enabling high spatial resolution and sensitive instruments, SALTUS will offer >80% of its available observing time to Guest Observer programs, providing the science community with powerful capabilities to study the local and distant universe with observations of 1000s of diverse targets such as distant and nearby galaxies, star-forming regions, protoplanetary disks, and solar system objects.

Abstract: A new method of digital signal processing of angle measuring systems based on digital antenna arrays is justified. It allows you to improve the image quality of one- and two-dimensional objects. The method can be applied in the optical, infrared, and terahertz ranges of electromagnetic wavelengths. In the process of numerical experiments, the effectiveness of the proposed method is compared with the known ones. The results of experiments on mathematical models are presented and discussed.

Abstract: The imaging performance and sensitivity of an X-ray telescope when observing astrophysical sources are primarily governed by the optical design, geometrical uncertainties (figure errors, surface roughness, and mirror alignment inaccuracies), and the reflectivity properties of the X-ray reflecting mirror surface. To thoroughly evaluate the imaging performance of an X-ray telescope with an optical design similar to Wolter-1 optics, which comprises multiple shells with known geometrical uncertainties and mirror reflectivity properties, appropriate computational tools are essential. These tools are used to estimate the angular resolution and effective area for various source energies and locations and, more importantly, to assess the impact of figure errors on the telescope's imaging performance. Additionally, they can also be used to optimize optics geometry by modifying it in reference to the Wolter-1 optics, aiming to minimize the optical aberration associated with the Wolter-1 configuration. In this paper, we introduce DarsakX, a Python-based ray tracing computational tool specifically designed to estimate the imaging performance of a multi-shell X-ray telescope. DarsakX has the capability to simulate the impact of figure errors present in the axial direction of a mirror shell. The geometrical shape of the mirror shells can be defined as a combination of figure error with the base optics, such as Wolter-1 or Conical optics. Additionally, DarsakX allows the exploration of new optical designs involving two reflections similar to Wolter-1 optics but with an improved angular resolution for wide-field telescopes. Developed through an analytical approach, DarsakX ensures computational efficiency, enabling fast processing.

Abstract: We present contemporaneous high-angular-resolution millimeter imaging and visible polarimetric imaging of the nearby asymptotic giant branch (AGB) star W Hya to better understand the dynamics and dust formation within a few stellar radii. The star W Hya \ was observed in two vibrationally excited H$_2$O lines at 268 and 251 GHz with Atacama Large Millimeter/submillimeter Array (ALMA) at a spatial resolution of 16times 20 mas and at 748 and 820 nm at a resolution of 26times 27 mas with the Very Large Telescope (VLT)/Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE)-Zurich Imaging Polarimeter (ZIMPOL). ALMA's high spatial resolution allowed us to image strong emission of the vibrationally excited H$_2$O \ line at 268 GHz ($ K_a,K_c $) over the stellar surface instead of absorption against the continuum, which is expected for thermal excitation. Strong, spotty emission was also detected along and just outside the stellar disk limb at an angular distance of sim 40 mas (sim 1.9 $R_ star ), extending to sim 60 mas (sim 2.9 $R_ star ). Another H$_2$O \ line ($ K_a,K_c $) at 251 GHz with a similar upper-level energy was tentatively identified, which shows absorption over the stellar surface. This suggests that the emission over the surface seen in the 268 GHz H$_2$O \ line is suprathermal or even maser emission. The estimated gas temperature and H$_2$O \ density are consistent with the radiatively pumped masers. The 268 GHz H$_2$O \ line reveals global infall at up to sim 15 km s$^ within 2--3 $R_ star but outflows at up to sim 8 km s$^ \ are also present. The polarized intensity maps obtained in the visible reveal clumpy dust clouds forming within sim 40 mas (sim 1.9 $R_ star ) with a particularly prominent cloud in the SW quadrant and a weaker cloud in the east. The 268 GHz H$_2$O \ emission overlaps very well with the visible polarized intensity maps, which suggests that both the nonthermal and likely maser H$_2$O \ emission and the dust originate from dense, cool pockets in the inhomogeneous atmosphere within sim 2--3 $R_ star

Abstract: Abstract Type-I solar noise storms are perhaps the most commonly observed active radio emissions from the Sun at meter-wavelengths. Noise storms have a long-lived and wideband continuum background with superposed islands of much brighter narrowband and short-lived emissions, known as type-I bursts. There is a serious paucity of studies focusing on the morphology of these two types of emissions, primarily because of the belief that coronal scattering will always wash out any features at small angular scales. However, it is important to investigate their spatial structures in detail to make a spatio-temporal connection with observations at extreme-ultraviolet/X-ray bands to understand the detailed nature of these emissions. In this work, we use high angular resolution observations from the upgraded Giant Metrewave Radio Telescope to demonstrate that it is possible to detect structures with angular scales as small as ∼9″, about three times smaller than the smallest structure reported to date from noise storms. Our observations also suggest that while the individual type-I bursts are narrowband in nature, the bursts are probably caused by traveling disturbance(s) inducing magnetic reconnections at different coronal heights, and thus leading to correlated change in the morphology of the type-I bursts observed at a wide range of frequencies.

Abstract: We use the VERITAS imaging air Cherenkov Telescope (IACT) array to obtain the first measured angular diameter of $β$ UMa at visual wavelengths using stellar intensity interferometry (SII) and independently constrain the limb-darkened angular diameter. The age of the Ursa Major moving group has been assessed from the ages of its members, including nuclear member Merak ($β$ UMa), an A1-type subgiant, by comparing effective temperature and luminosity constraints to model stellar evolution tracks. Previous interferometric limb-darkened angular-diameter measurements of $β$ UMa in the near-infrared (CHARA Array, $1.149 \pm 0.014$ mas) and mid-infrared (Keck Nuller, $1.08 \pm 0.07$ mas), together with the measured parallax and bolometric flux, have constrained the effective temperature. This paper presents current VERITAS-SII observation and analysis procedures to derive squared visibilities from correlation functions. We fit the resulting squared visibilities to find a limb-darkened angular diameter of $1.07 \pm 0.04 {\rm (stat)} \pm 0.05$ (sys) mas, using synthetic visibilities from a stellar atmosphere model that provides a good match to the spectrum of $β$ UMa in the optical wave band. The VERITAS-SII limb-darkened angular diameter yields an effective temperature of $9700\pm200\pm 200$ K, consistent with ultraviolet spectrophotometry, and an age of $390\pm 29 \pm 32 $ Myr, using MESA Isochrones and Stellar Tracks (MIST). This age is consistent with $408 \pm 6$ Myr from the CHARA Array angular diameter.

Abstract: Recently, many deep neural network based methods have been proposed for light field (LF) image super-resolution (SR). Although these methods have shown consistent improvement and yield visually pleasing outcomes, the diverse spatial-angular correlations embedded in light fields are still underexploited, which is crucial for LF image SR. In this paper, we exploit the Omni Spatial-Angular Correlations (OSAC) of LFs. OSAC has three types of correlations: Intra-SAC, Inter-SAC, and Geometry-SAC. Intra-SAC learns separate spatial and angular representations inside a sub-aperture image (SAI) and macro-pixel image (MacPI). Inter-SAC learns complementary contextual information and depth variation information on SAI arrays and macro-pixel arrays. Geometry-SAC learns sub-pixel shift information on epipolar plane images (EPI). To achieve efficient OSAC learning for LF image SR, we develop a network named OSANet equipped with Omni Spatial-Angular Correlations Exploration blocks, which can fully incorporate the comprehensive SACs of LFs. Extensive experiments are carried out on five LF benchmarks, and the results show our methods’ superiority both qualitatively and quantitatively. Code is available at https://github.com/stanley-313/OSANet

Abstract: Detecting mid-infrared (MIR) radiation has significant astronomical applications, although limited by unsatisfactory MIR detectors. Here we reported on the realization of a MIR up-conversion interferometer based on synthetic long base-line (SLBL) in the laboratory. The experimental system consisted of an interferometer and subsequent up-conversion detection part of mid-infrared signal, which streamlined the structure and enhanced the reliability of the system. By using a tungsten filament lamp as an imitated star, we not only achieved the single target angle resolution of 1.10 times 10^(-4) rad, but also obtained the field angle resolution of 3.0 times 10^(-4) rad of double star targets. The angular resolution is in inverse proportion to the length of baseline. The maximum length of simulated baseline in the laboratory is about 3cm. In a Keck Interferometer (KI) liked program, the base line can reach up to 85m leading to a corresponding angular resolution of 3.0 times 10^(-9) rad (about 1.8mas). The study will offer potential benefits in extending the usage of mid-infrared light in astronomical exploration.

Abstract: The full array of the Large High Altitude Air Shower Observatory (LHAASO) has been in operation since July 2021. For its kilometer-square array (KM2A), we have optimized the selection criteria for very high and ultra-high energy $\gamma$-rays, using the data collected from August 2021 to August 2022, resulting in an improvement on significance of about 15$\%$ compared with previous cuts. With the implementation of these new selection criteria, the angular resolution is also significantly improved by approximately 10$\%$ at tens of TeV. Other aspects of the full KM2A array performance, such as the pointing error are also calibrated using the Crab Nebula. The resulting energy spectrum of the Crab Nebula in the energy range of 10-1000 TeV can be well fitted by a log-parabola model, which is consistent with the previous results from LHAASO and other experiments.

Abstract: Abstract This article reports the first observation of the Moon and the Sun shadows in the sky distribution of cosmic-ray induced muons measured by the KM3NeT/ORCA detector. The analysed data-taking period spans from February 2020 to November 2021, when the detector had 6 Detection Units deployed at the bottom of the Mediterranean Sea, each composed of 18 Digital Optical Modules. The shadows induced by the Moon and the Sun were detected at their nominal position with a statistical significance of 4.2 $$\sigma $$ σ and 6.2 $$\sigma $$ σ , and an angular resolution of $$\sigma _{res}=0.49^\circ $$ σ res = 0 . 49 ∘ and $$\sigma _{res}=0.66^\circ $$ σ res = 0 . 66 ∘ , respectively, consistent with the prediction of $$0.53^\circ $$ 0 . 53 ∘ from simulations. This early result confirms the effectiveness of the detector calibration, in time, position and orientation and the accuracy of the event direction reconstruction. This also demonstrates the performance and the competitiveness of the detector in terms of pointing accuracy and angular resolution.

Abstract: The IceCube Neutrino Observatory relies on an array of photomultiplier tubes to detect Cherenkov light produced by charged particles in the South Pole ice. IceCube data analyses depend on an in-depth characterization of the glacial ice, and on novel approaches in event reconstruction that utilize fast approximations of photoelectron yields. Here, a more accurate model is derived for event reconstruction that better captures our current knowledge of ice optical properties. When evaluated on a Monte Carlo simulation set, the median angular resolution for in-ice particle showers improves by over a factor of three compared to a reconstruction based on a simplified model of the ice. The most substantial improvement is obtained when including effects of birefringence due to the polycrystalline structure of the ice. When evaluated on data classified as particle showers in the high-energy starting events sample, a significantly improved description of the events is observed.

Abstract: One of the main objectives of the ANTARES telescope is the search for point-like neutrino sources. Both the pointing accuracy and the angular resolution of the detector are important in this context and a reliable way to evaluate this performance is needed. In order to measure the pointing accuracy of the detector, one possibility is to study the shadow of the Moon, i.e. the deficit of the atmospheric muon flux from the direction of the Moon induced by the absorption of cosmic rays. Analysing the data taken between 2007 and 2016, the Moon shadow is observed with $3.5\sigma$ statistical significance. The detector angular resolution for downward-going muons is 0.73$^{\circ}\pm0.14^{\circ}.$ The resulting pointing performance is consistent with the expectations. An independent check of the telescope pointing accuracy is realised with the data collected by a shower array detector onboard of a ship temporarily moving around the ANTARES location.

Abstract: Resolved molecular line observations are essential for gaining insight into the physical and chemical structure of protoplanetary disks, particularly in cold, dense regions where planets form and acquire compositions. However, tracing these regions is challenging because most molecules freeze onto grain surfaces and are not observable in the gas phase. We investigated cold molecular chemistry in the triple stellar T Tauri disk GG Tau A, which harbours a massive gas and dust ring and an outer disk, using ALMA Band 7 observations. We present high angular resolution maps of N2H+ and DCO+ emission, with upper limits reported for H2D+, 13CS, and SO2. The radial intensity profile of N2H+ shows most emission near the ring outer edge, while DCO+ exhibits double peaks, one near the ring inner edge and the other in the outer disk. With complementary observations of lower-lying transitions, we constrained the molecular surface densities and rotation temperatures. We compared the derived quantities with model predictions across different cosmic ray ionization (CRI) rates, carbon-to-oxygen (C/O) ratios, and stellar UV fluxes. Cold molecular chemistry, affecting N2H+, DCO+, and H2D+ abundances, is most sensitive to CRI rates, while stellar UV flux and C/O ratios have minimal impact on these three ions. Our best model requires a low cosmic ray ionization rate of 1e-18 s-1. However, it fails to match the low temperatures derived from N2H+ and DCO+, 12 to 16 K, which are much lower than the CO freezing temperature.

Abstract: The S-band Polarisation All Sky Survey (SPASS/ATCA) rotation measure (RM) catalogue is the largest broadband RM catalogue to date, increasing the RM density in the sparse southern sky. Through analysis of this catalogue, we report a latitude dependency of the Faraday complexity of polarised sources in this catalogue within 10$^\circ$ of the Galactic plane towards the inner Galaxy. In this study, we aim to investigate this trend with follow-up observations using the Australia Telescope Compact Array (ATCA). We observe 95 polarised sources from the SPASS/ATCA RM catalogue at 1.1 - 3.1 GHz with ATCA's 6 km configuration. We present Stokes QU fitting results and a comparative analysis with the SPASS/ATCA catalogue. We find an overall decrease in complexity in these sources with the higher angular resolution observations, with a complexity fraction of 42\%, establishing that the majority of the complexity in the SPASS/ATCA sample is due to the mixing-in of diffuse Galactic emission at scales $θ> 2.8'$. Furthermore, we find a correlation between our observed small-scale complexity $θ< 2.8'$ and the Galactic spiral arms, which we interpret to be due to Galactic turbulence or small-scale polarised emission. These results emphasise the importance of considering the maximum angular scale to which the observations are sensitive in the classification of Faraday complexity; the effect of which can be more carefully investigated with SKA-precursor and pathfinder arrays (e.g. MeerKAT and ASKAP).