Small Telescopes Research Articles

Cognitive Control and the Implicit Association Test: A Replication of Siegel, Dougherty, and Huber (2012)

The implicit association test (IAT) is widely used to measure evaluative associations towards groups or the self but is influenced by other traits. Siegel, Dougherty, and Huber (2012, Journal of Experimental Social Psychology) found that manipulating cognitive control via false feedback (Study 3) changed the degree to which the IAT was related to cognitive control versus evaluative associations. We conducted two replications of this study and a mini meta-analysis. Null-hypothesis tests, meta-analysis, and a small telescope approach demonstrated weak to no support for the original hypotheses. We conclude that the original findings are unreliable and that both the original study and our replications do not provide evidence that manipulating cognitive control affects IAT scores.

Dust Production of Interstellar Comet 2I/Borisov Throughout Perihelion

Abstract The recently discovered comet 2I/Borisov quickly became a prime target for comet observers during its perihelion approach in 2019 December, after it was discovered to be the first comet of interstellar origin. We present our observations and measurements of the dust production between 2019 October, when the interstellar comet became bright enough for small aperture telescopes, and 2020 January, when the comet entered the plane of the Milky Way. We observed the comet for 24 nights using three telescopes in the public iTelescope network. The telescopes spanned both the Northern and Southern hemispheres, were of similar aperture size (0.43–0.51 m), and employed a Johnson–Cousins R C filter. Using these data, we measure an A(0°)f ρ range of 94 ± 14 to 139 ± 34 cm, a dust production rate Q dust range of 11.2 ± 4.4 to 16.4 ± 7.3 kg s−1, and a dust-brightness profile-parameter range of −0.95 ± 0.11 to −1.81 ± 0.20 for the interstellar comet. This work revealed low dust production rates from the comet that remained consistent throughout its apparition, with no notable brightening or increase in dust production throughout the observing campaign.

Deep co-added sky from Catalina Sky Survey images

ABSTRACT A number of synoptic sky surveys are underway or being planned. Typically, they are done with small telescopes and relatively short exposure times. A search for transient or variable sources involves comparison with deeper baseline images, ideally obtained through the same telescope and camera. With that in mind, we have stacked images from the 0.68 m Schmidt telescope on Mt. Bigelow taken over 10 yr as part of the Catalina Sky Survey. In order to generate deep reference images for the Catalina Real-time Transient Survey (CRTS), close to 0.8 million images over 8000 fields and covering over 27 000 sq. deg have gone into the deep stack that goes up to 3 mag deeper than individual images. CRTS system does not use a filter in imaging; hence, there is no standard passband in which the optical magnitude is measured. We estimate depth by comparing these wide-band unfiltered co-added images with images in the g band and find that the image depth ranges from 22.0 to 24.2 across the sky, with a 200-image stack attaining an equivalent AB magnitude sensitivity of 22.8. We compared various state-of-the-art software packages for co-adding astronomical images and have used swarp for the stacking. We describe here the details of the process adopted. This methodology may be useful in other panoramic imaging applications, and to other surveys as well. The stacked images are available through a server at Inter-University Centre for Astronomy and Astrophysics.

Absolute detection of atmospheric temperature by using a scanning Fabry-Pérot interferometer in high spectral resolution lidar

In order to achieve a high signal-to-noise ratio by using small laser energy and telescope aperture, we present a detection method based on Rayleigh-Brillouin scattering (RBS) for the measurement of atmospheric temperature without response functions and calibration procedures by using high spectral resolution lidar (HSRL). Different from the traditional HSRL, a Fabry-Pérot interferometer (FPI) with a continuous tunable cavity and polarization optical scheme are employed in a high spectral resolution filter. In order to continuously change the resonant frequency of the FPI, an electro-optical crystal of potassium dideuterium phosphate (DKDP) with two ring electrodes is used as a continuous tunable cavity in the FPI. At each scanned frequency point corresponded with the resonant frequency of the FPI, the received signals of four discrete points on RBS are obtained. Atmospheric temperature is inverted by using a RBS model. The polarization optical scheme is used to suppress the solar background light, and improve the utilization of return signals. In detection experiment of atmospheric temperature, the detection height is 2 km at night and 1.5 km during the day by using a pulsed energy of 30 mJ and telescope diameter of 250 mm. The results are in good agreement with the data detected by radiosonde.

The research objectives and observational possibilities for fast moving near-Earth asteroids

The paper describes observations of fast-moving near-Earth asteroids (NEAs) made with the small ground-based telescopes of National Time Service Center of Chinese Academy of Science (NTSC of CAS) and Research Institute “Mykolaiv Astronomical Observatory” (RI MAO) by the rotating-drift-scan CCD (RDS CCD) technique. This technique is used to obtain the point images of both the studied objects and reference stars. The results of ongoing follow-up observations of NEAs are discussed. The residual differences (O – C) between the observed and calculated positions from JPL ephemeris were generally small for these asteroids. The standard deviations of these differences were typically ±(0.2″ – 0.3″) in both coordinates for objects with apparent velocity which substantially exceed FWHM for the given exposure time. The results of comparative statistics for such observations from the MPC database show that this is a good level of precision for NEAs. Moreover, the telescopes with the RDS CCD technique implemented can observe the NEAs that closely approach the Earth and with enough observations can improve the precision of determining their orbital elements and impact predictions.

A survey for variable young stars with small telescopes – IV. Rotation periods of YSOs in IC 5070

ABSTRACT Studying rotational variability of young stars is enabling us to investigate a multitude of properties of young star-disc systems. We utilize high cadence, multiwavelength optical time series data from the Hunting Outbursting Young Stars citizen science project to identify periodic variables in the Pelican Nebula (IC 5070). A double blind study using nine different period-finding algorithms was conducted and a sample of 59 periodic variables was identified. We find that a combination of four period finding algorithms can achieve a completeness of 85 per cent and a contamination of 30 per cent in identifying periods in inhomogeneous data sets. The best performing methods are periodograms that rely on fitting a sine curve. Utilizing Gaia EDR3 data, we have identified an unbiased sample of 40 periodic young stellar objects (YSOs), without using any colour or magnitude selections. With a 98.9 per cent probability, we can exclude a homogeneous YSO period distribution. Instead, we find a bi-modal distribution with peaks at 3 and 8 d. The sample has a disc fraction of 50 per cent, and its statistical properties are in agreement with other similarly aged YSOs populations. In particular, we confirm that the presence of the disc is linked to predominantly slow rotation and find a probability of 4.8 × 10−3 that the observed relation between period and presence of a disc has occurred by chance. In our sample of periodic variables, we also find pulsating giants, an eclipsing binary, and potential YSOs in the foreground of IC 5070.

Asteroid Photometry with PIRATE: Optimizations and Techniques for Small Aperture Telescopes

Small aperture telescopes provide the opportunity to conduct high frequency, targeted observations of near-Earth Asteroids that are not feasible with larger facilities due to highly competitive time allocation requirements. Observations of asteroids with these types of facilities often focus on rotational brightness variations rather than longer-term phase angle-dependent variations (phase curves) due to the difficulty of achieving high precision photometric calibration. We have developed an automated asteroid light curve extraction and calibration pipeline for images of moving objects from the 0.43 m Physics Innovations Robotic Telescope Explorer. This allows for the frequency and quality of observations required to construct asteroid phase curves. Optimizations in standard data reduction procedures are identified that may allow for similar small aperture facilities, constructed from commercially available/off-the-shelf components, to improve the image and subsequent data quality. A demonstration of the hardware and software capabilities is expressed through observation statistics from a 10 months observing campaign, and through the photometric characterization of near-Earth Asteroids 8014 (1990 MF) and 19764 (2000 NF5).

Faster Exo-Earth yield for HabEx and LUVOIR via extreme precision radial velocity prior knowledge

The HabEx and LUVOIR mission concepts reported science yields for mission scenarios in which the instruments must search for potentially habitable planets, determine their orbits, and, if worthwhile, invest the integration time for a spectral characterization. We evaluate the impact of prior knowledge of planet existence and orbital parameters on yield for four mission concept architectures: HabEx 4m telescope with hybrid starshade and coronagraph, HabEx 4m telescope with starshade only, HabEx 4m telescope with coronagraph only, and LUVOIR B 8m telescope with coronagraph only. We use perfect prior knowledge to establish an upper bound on yield and use partial prior knowledge from a potential future extreme precision radial velocity (EPRV) instrument with 3 cm / s sensitivity. We detail a modeling framework that performs dynamically responsive observation scheduling with realistic mission constraints. We evaluate exo-Earth yields against three metrics of spectral characterization for the four mission architectures and three levels of prior knowledge (none, partial, and perfect). The EPRV provided prior knowledge increases yields by ∼30 % and accelerates by a factor of 3 to 6 the time to achieve half of the yield of the mission. Prior knowledge makes all the mission architectures more nimble and powerful, and most especially starshade-based architectures. With prior knowledge, a small telescope with a starshade can achieve comparable yield to a larger telescope with a coronagraph.

A numerical study of long-term multiwavelength blazar variability

ABSTRACT Decade-long monitoring of blazars at optical and infrared (OIR) wavelengths with the Small and Moderate Aperture Research Telescope System (SMARTS) in Chile and in γ-rays with the Fermi -Large Area Telescope (LAT) has enabled the systematic study of their multiwavelength long-term variability. In this work, we investigate, from a theoretical perspective, the long-term variability properties of blazar emission by introducing an observationally motivated time-dependence to four main parameters of the one-zone leptonic model: injection luminosity of relativistic electrons, strength of magnetic field, Doppler factor, and external photon field luminosity. For the first time, we use both the probability density function and the power spectral density of the 10-yr-long Fermi-LAT light curves to create variation patterns for the model parameters. Using as test beds two bright blazars from the SMARTS sample (PKS 2155−304 and 3C 273), we compute 10-yr-long OIR, X-ray, and γ-ray model light curves for different varying parameters. We compare the findings of our theoretical investigation with multiwavelength observations using various measures of variability. While no single-varying parameter simulation can explain all multiwavelength variability properties, changes in the electron luminosity and external radiation field in PKS 2155−304 and 3C 273, respectively, can account for most of them. Our results motivate future time-dependent studies with coupling between two or more physical parameters to describe the multiwavelength long-term blazar variability.

Somangnet: Small Telescope Network of Korea

Even in an era where 8-meter class telescopes are common, small telescopes are considered very valuable research facilities since they are available for rapid follow-up or long term monitoring observations. To maximize the usefulness of small telescopes in Korea, we established the SomangNet, a network of 0.4-1.0 m class optical telescopes operated by Korean institutions, in 2020. Here, we give an overview of the project, describing the current participating telescopes, its scientific scope and operation mode, and the prospects for future activities. SomangNet currently includes 10 telescopes that are located in Australia, USA, and Chile as well as in Korea. The operation of many of these telescopes currently relies on operators, and we plan to upgrade them for remote or robotic operation. The latest SomangNet science projects include monitoring and follow-up observational studies of galaxies, supernovae, active galactic nuclei, symbiotic stars, solar system objects, neutrino/gravitational-wave sources, and exoplanets.

Point spread function estimation for wide field small aperture telescopes with deep neural networks and calibration data

ABSTRACT The point spread function (PSF) reflects states of a telescope and plays an important role in the development of data-processing methods, such as PSF-based astrometry, photometry, and image restoration. However, for wide field small aperture telescopes (WFSATs), estimating PSF in any position of the whole field of view is hard, because aberrations induced by the optical system are quite complex and the signal-to-noise ratio of star images is often too low for PSF estimation. In this paper, we further develop our deep neural network (DNN)-based PSF modelling method and show its applications in PSF estimation. During the telescope alignment and testing stage, our method collects system calibration data through modification of optical elements within engineering tolerances (tilting and decentring). Then, we use these data to train a DNN (Tel–Net). After training, the Tel–Net can estimate PSF in any field of view from several discretely sampled star images. We use both simulated and experimental data to test performance of our method. The results show that the Tel–Net can successfully reconstruct PSFs of WFSATs of any states and in any positions of the field of view (FoV). Its results are significantly more precise than results obtained by the compared classic method – inverse distance weight interpolation. Our method provides foundations for developing deep neural network-based data-processing methods for WFSATs, which require strong prior information of PSFs.

Precise Estimation of Source Intensity for Wide-field Telescopes with PSF Modeling

Abstract Wide-field small aperture optical telescopes are widely used in large-scale surveys currently and they have made great contributions in a number of astronomical applications. However, specific challenges arise owing to the defects caused by the optical system, and the image quality and reduction precision are negatively affected. An innovative method is proposed to address these challenges and achieve a high-precision source intensity estimation. In implementation, first a dedicated pipeline is developed to investigate the point-spread function (PSF) components from large amounts of images, using principal component analysis. Then the PSF model that reveals the actual characteristics of the optical system is constructed based on the evaluation. Last the equations for centroid and intensity estimation are constructed and the results are obtained. A trial of observations is performed with a wide-field small aperture telescope, and a large number of raw images, as well as simulated images, are acquired to test the efficiency of our method. The intensity measurement is performed with our method and other common algorithms, including the modified moment, Gaussian fitting, and SExtractor. Based on the comparison it is demonstrated that our proposed method outperforms the others. The results indicate that our method explores the limitations of such a system and additional gains can be achieved in wider applications.

Multiwavelength study of the quiescent states of six brightest flat-spectrum radio quasars detected by Fermi-LAT

ABSTRACT The regular monitoring of flat-spectrum radio quasars (FSRQs) in γ-rays by Fermi-LAT (Large Area Telescope) since past 12 yr indicated six sources who exhibited extreme γ-ray outbursts crossing daily flux of 10−5 photons cm−2 s−1. We obtained nearly simultaneous multiwavelength data of these sources in radio to γ-ray waveband from OVRO (Owens Valley Radio Observatory), Steward Observatory, SMARTS (Small and Moderate Aperture Research Telescope System), Swift-UVOT (UV/Optical Telescope), Swift-XRT (X-ray Telescope), and Fermi-LAT. The time-averaged broad-band spectral energy distributions (SEDs) of these sources in quiescent states were studied to get an idea about the underlying baseline radiation processes. We modelled the SEDs using one-zone leptonic synchrotron and inverse Compton emission scenario from broken power-law electron energy distribution inside a spherical plasma blob, relativistically moving down a conical jet. The model takes into account inverse Compton scattering of externally and locally originated seed photons in the jet. The big blue bumps visible in quiescent state SEDs helped to estimate the accretion disc luminosities and central black hole masses. We found a correlation between the magnetic field inside the emission region and the ratio of emission region distance to disc luminosity, which implies that the magnetic field decreases with an increase in emission region distance and decrease in disc luminosity, suggesting a disc–jet connection. The high-energy index of the electron distribution was also found to be correlated with observed γ-ray luminosity as γ-rays are produced by high-energy particles. In most cases, kinetic power carried by electrons can account for jet radiation power as jets become radiatively inefficient during quiescent states.

Proof of concept for through silicon vias in application-specific integrated circuits for hard x-ray imaging detectors

Application-specific integrated circuits (ASICs) are commonly used to efficiently process the signals from sensors and detectors in space. Wire bonding is a space-qualified technique of making interconnections between ASICs and their substrate packaging board for power, control, and readout of the ASICs. Wire bonding is nearly ubiquitous in modern space programs, but their exposed wires can be prone to damage during assembly and subject to electric interference during operations. Additional space around the ASICs needed for wire bonding also impedes efficient packaging of large arrays of detectors. Here, we introduce the through silicon vias (TSV) technology that replaces wire bonds and eliminates their shortcomings. We have successfully demonstrated the feasibility of implementing TSVs to existing ASIC wafers (a.k.a. a via-last process) developed for processing the x-ray signals from the x-ray imaging CdZnTe detectors on the Nuclear Spectroscopic Telescope Array small explorer telescope mission that was launched in 2012. While TSVs are common in the semiconductor industry, this is the first (to our knowledge) successful application for astrophysics imaging instrumentation. We expect that the TSV technology will simplify the detector assembly and thus will enable significant cost and schedule savings in assembly of large area CdZnTe detectors.

Observing Solar Limb Darkening in the Classroom

The falling temperature of the photosphere with height is responsible for the effect known as limb darkening. The Sun is not equally bright all over the disc. When we observe the Sun towards the limbs, it appears to get darker. Light from the photosphere travels through an absorptive medium. Therefore, one can see only so far into the photosphere. This is the optical depth (Fig. 1). The line of sight at the center sees deeper into the Sun to an optical depth of about 2/3 into the photosphere. In other words, photons that escape from a smaller radius of the photosphere have originated in a hotter region; therefore, they will have a higher intensity. Photons that originate from a larger radius come from a cooler part of the photosphere; therefore, this results in lower intensity. This effect is known as solar limb darkening. In addition, the solar photosphere displays various phenomena that can easily be observed in images obtained with small telescopes, such as sunspots, faculae, and granulation. Limb darkening results from the fact that we are looking into hot gas when we look at the Sun and, as a consequence of this, the brightness of the Sun decreases as one looks from the center of the disc (where we see deeper inside the Sun) towards the limb (where we will not see as deeply into the solar atmosphere because we are looking at a slant through the photospheric material).

Design and development of Mt.Abu faint object spectrograph and camera – Pathfinder (MFOSC-P) for PRL 1.2m Mt. Abu Telescope

Mt. Abu Faint Object Spectrograph and Camera - Pathfinder (MFOSC-P) is an imager-spectrograph developed for the Physical Research Laboratory (PRL) 1.2m telescope at Gurushikhar, Mt. Abu, India. MFOSC-P is based on a focal reducer concept and provides seeing limited imaging (with a sampling of 3.3 pixels per arc-second) in Bessell's B, V, R, I and narrow-band H-$\alpha$ filters. The instrument uses three plane reflection gratings, covering the spectral range of 4500-8500$\AA$, with three different resolutions of 500, 1000, and 2000 around their central wavelengths. MFOSC-P was conceived as a pathfinder instrument for a next-generation instrument on the PRL's 2.5m telescope which is coming up at Mt. Abu. The instrument was developed during 2015-2019 and successfully commissioned on the PRL 1.2m telescope in February 2019. The designed performance has been verified with laboratory characterization tests and on-sky commissioning observations. Different science programs covering a range of objects are being executed with MFOSC-P since then, e.g., spectroscopy of M-dwarfs, novae $\&$ symbiotic systems, and detection of H-$\alpha$ emission in star-forming regions. MFOSC-P presents a novel design and cost-effective way to develop a FOSC (Faint Object Spectrograph and Camera) type of instrument on a shorter time-scale of development. The design and development methodology presented here is most suitable in helping the small aperture telescope community develop such a versatile instrument, thereby diversifying the science programs of such observatories.

Laparoscopic Cholecystectomy under Segmental Thoracic Spinal Anesthesia

Introduction: Cholelithiasis or gallstones are hardened deposits of digestive fluid that can form in gallbladder. The treatment of gallstones depends upon the stage of disease. Once gallstones become symptomatic, definitive surgical intervention with cholecystectomy is usually indicated (typically, laparoscopic cholecystectomy is the first-line therapy). Laparoscopic cholecystectomy removes the gallbladder and gallstones through several small incisions in the abdomen. This case report aims to discuss the managent of segmental thoracic spinal anesthesia in laparoscopic cholecystectomy.
 Case: We report on the cases of 2 patients who undego elective laparoscopic cholecystectomy. Female, 53 years old, will undergo laparoscopic cholecystectomy, performed anesthesia with segmental thoracic spinal anesthesia technique using the anesthetic agent 3 ml of Levobupivacaine 0,5% + 25 mcg of Fentanyl, requiring a sensory block to at least T10-T11 dermatom. Patients received a 1,2 mcg target control infusion (TCI) propofol intravenous is administered as intermittent boluses to achieve deep sedation. The operation lasts 1 hour, with a bleeding 15 cc and urine output 100 cc, hemodynamically stable. Female, 42 years old, will undergo laparoscopic cholecystectomy, performed anesthesia with segmental thoracic spinal anesthesia technique using the anesthetic agent 3 ml of Levobupivacaine 0,5% + 25 mcg of Fentanyl, requiring a sensory block to at least T10-T11 dermatom. Patients received a 3 mg of midazolam intravenous is administered as intermittent boluses to achieve deep sedation. The operation lasts 1 hour, with a bleeding 15 cc and urine output 150 cc, hemodynamically stable. The level and duration of sensory block, intensity and duration of motor block were recorded. A 20 % or more decrease in MAP compared to baseline was considered as hypotension, iv ephedrine 5 mgr bolus administreted.
 Conclusion: Laparoscopy is a surgical procedure that uses minimally invasive surgical techniques (minimally invasive surgery) where the doctor uses a small telescope / camera that is inserted into the stomach and surgical instruments in mini form. This procedure has many advantages because it is not invasive, the amount of bleeding can be reduced, postoperative pain can be minimized. Regional anesthesia procedure in laparoscopic cholecystectomy based on several studies and case reports can be performed and is a safe procedure.

Laparoscopic Cholecystectomy under Segmental Thoracic Spinal Anesthesia

Introduction: Cholelithiasis or gallstones are hardened deposits of digestive fluid that can form in gallbladder. The treatment of gallstones depends upon the stage of disease. Once gallstones become symptomatic, definitive surgical intervention with cholecystectomy is usually indicated (typically, laparoscopic cholecystectomy is the first-line therapy). Laparoscopic cholecystectomy removes the gallbladder and gallstones through several small incisions in the abdomen. This case report aims to discuss the managent of segmental thoracic spinal anesthesia in laparoscopic cholecystectomy.
 Case: We report on the cases of 2 patients who undego elective laparoscopic cholecystectomy. Female, 53 years old, will undergo laparoscopic cholecystectomy, performed anesthesia with segmental thoracic spinal anesthesia technique using the anesthetic agent 3 ml of Levobupivacaine 0,5% + 25 mcg of Fentanyl, requiring a sensory block to at least T10-T11 dermatom. Patients received a 1,2 mcg target control infusion (TCI) propofol intravenous is administered as intermittent boluses to achieve deep sedation. The operation lasts 1 hour, with a bleeding 15 cc and urine output 100 cc, hemodynamically stable. Female, 42 years old, will undergo laparoscopic cholecystectomy, performed anesthesia with segmental thoracic spinal anesthesia technique using the anesthetic agent 3 ml of Levobupivacaine 0,5% + 25 mcg of Fentanyl, requiring a sensory block to at least T10-T11 dermatom. Patients received a 3 mg of midazolam intravenous is administered as intermittent boluses to achieve deep sedation. The operation lasts 1 hour, with a bleeding 15 cc and urine output 150 cc, hemodynamically stable. The level and duration of sensory block, intensity and duration of motor block were recorded. A 20 % or more decrease in MAP compared to baseline was considered as hypotension, iv ephedrine 5 mgr bolus administreted.
 Conclusion: Laparoscopy is a surgical procedure that uses minimally invasive surgical techniques (minimally invasive surgery) where the doctor uses a small telescope / camera that is inserted into the stomach and surgical instruments in mini form. This procedure has many advantages because it is not invasive, the amount of bleeding can be reduced, postoperative pain can be minimized. Regional anesthesia procedure in laparoscopic cholecystectomy based on several studies and case reports can be performed and is a safe procedure.

Detection of atmospheric temperature by using polarization high-spectral-resolution lidar.

In order to achieve high signal-to-noise ratio by using small laser energy and telescope aperture, we present a polarization filter in high-spectral-resolution lidar (HSRL) for the measurement of atmospheric temperature. Compared with the filter method in a traditional HSRL in which the intensity of the return signal is split into the different transmission channel of a discriminator, the advantage of this filter system is that the intensity of the return signal is fully utilized for each discriminator channel, and the return signal changes the polarization state of the light without loss of intensity when it is incident on the two Rayleigh channels. In addition, the daytime detection capability of HSRL is improved by using a polarization optical scheme to suppress the solar background light. The advantages of the polarization filter are proven by the theoretical calculations using the Stokes vector and a Mueller matrix. In detection experiments of atmospheric temperature, the detection height is 4 km at night and 2.5 km during the day by using the pulsed energy of 50 mJ and telescope diameter of 250 mm. The results are in good agreement with the data detected by radiosonde.

The Telescope-in-a-Box — A Collapsible Open-Frame Dobsonian Telescope for Student Astronomy Projects

The telescope-in-a-box is a small objective ultralight Dobsonian telescope concept that will be accompanied by telescope instrumentation lesson plans. This provides a rich set of opportunities for teaching astronomy, physics and engineering. Our first two prototypes demonstrate that it can be constructed at low cost, while many of the design decisions can lead to lesson plans in telescope instrumentation.