- ID:
- ivo://CDS.VizieR/B/occ
- Title:
- Occultation lights curves
- Short Name:
- B/occ
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Lunar occultation light curves have been recorded since the mid-20th century using high-speed photomultipliers. Running at high cadence for high angular resolution, such recordings were usually made on large telescopes and limited to the brighter stars - and were not large in number. While a small number of video recordings of lunar and asteroidal occultations were made from about 1980, they became common from about the year 2000, when inexpensive low-light security cameras became available. As of 2016, almost all lunar and asteroidal occultation observations are recorded using video, with the video recording being measured using software packages such as Limovie [http://astro-limovie.info/limovie/limovie_en.html], and Tangra [http://www.hristopavlov.net/Tangra3/]. As a result, light curves are now routinely generated for almost all lunar and asteroidal occultation observations, especially those coordinated through the International Occultation Timing Association and related organisations around the world. This is resulting in large numbers of occultation light curves being obtained each year - albeit with some limitations on time resolution and signal-to-noise ratios. As of 2016, video recordings are mainly made using one or other of the two international video standards - NTSC, or PAL. Both NTSC and PAL use an interlaced video scan, whereby each frame of the video is comprised of two interlaced, time-sequential, fields. The frame rate of an NTSC system is 29.97 frames/sec (59.94 fields/sec), while that for PAL is 25 frames/sec ( 50 fields/sec). Consistent with broadcast television standards, the majority of video cameras used for recording occultations use 8-bit CCD's. However some video recordings are made using progressive scan, 12 to 16-bit digital video systems. For lunar occultations, the temporal resolution is governed by a combination of the frame (or field) rate of the video recording, and the rate of motion of the moon. The typical topocentric motion of the moon is between about 0.3"/sec and 0.4"/sec. The motion of the lunar limb in a direction normal to the star is reduced by the cosine of the difference between the direction of motion of the moon and the position angle of the star. As a result, the typical rate of motion of the lunar limb normal to the star is in the range 0.2 to 0.4 "/sec. At video frame rates this provides a spatial resolution of about 0.01" to 0.02" at frame rate, or 0.005" to 0.01" at field rate. In recent years it has been possible to accurately determine the orientation of the lunar limb at the point of an occultation, using data from the Japanese Kaguya satellite, and more recently the US Lunar Reconnaissance Orbiter - Lunar Orbiter Laser Altimeter (LRO-LOLA). The LRO-LOLA data allows the slope of the lunar limb to be reliably determined over circumferential distances of less than 0.2" in the sky plane. As a result, all data elements required to analyse a lunar occultation light curve are well determined - and are included in this archive. The motion of most asteroids is much less than the moon. As a result, the angular resolution attainable at video frame rate is much smaller than for a lunar occultation, and is commonly in the range 0.0001" to 0.001". However asteroidal occultations frequently involve fainter objects than for lunar occultations, and many observers use integrating video cameras to detect these fainter occultations; the resolution attainable with an integrating camera is reduced in proportion to the number of frames integrated. Unlike lunar occultations, the orientation of the occulting limb of an asteroid relative to the star is generally not well established. Furthermore it can generally be assumed that the limb of an asteroid is likely to have significant irregularities at scales greater than the potential angular resolution attainable, but smaller than the angular distance between adjacent observed occultation chords. There is also the issue of the rotational orientation of the asteroid differing for observers located at different points along the occultation path, placing a limit on the accuracy of the limb slope that can be derived from adjacent occultation chords. Accordingly, at this time the record does not attempt to specify the orientation of the limb of the asteroid at the occultation event.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/556/A118
- Title:
- Occultation of HIP 107302 by Jupiter
- Short Name:
- J/A+A/556/A118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Occultations of bright stars by planets provide information on the state of their atmospheres. An occultation of the bright star 45 Capricornii (HIP 107302) by Jupiter occurred on the night of 3/4 August 2009. The event was observed at multiple sites in Europe, Africa and South America and with instruments ranging in aperture from 0.4m to 2.2m. All observations, except one, were carried out in methane absorption bands centred at 0.89um and 2.2um to minimise the planetary contribution to the measured stellar flux. Following the application of special post-processing techniques, differential photometry was performed. Nearby bright satellites were used as reference sources.
- ID:
- ivo://CDS.VizieR/J/AJ/109/1363
- Title:
- Occultations of stars by asteroids 1995-96
- Short Name:
- J/AJ/109/1363
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Predictions, based on a computerized comparison of asteroid ephemerides with the catalog positions of 567,500 stars, are given for 155 occultations of stars by asteroids in 1995 and 1996. On average, the predictions are expected to be more accurate than in earlier searches because of the use of more modern star catalogs. A number of very favorable occultations, visible in North Armerica and elsewhere, are discussed.
- ID:
- ivo://CDS.VizieR/J/PAZh/30/692
- Title:
- Occultations of stars by large TNO 2004-2014
- Short Name:
- J/PAZh/30/692
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Occultations of stars brighter than 15m by largest trans-Neptunian objects (TNOs) are predicted. Search was performed using the following catalogues: Hipparcos (Cat. <I/239>; Tycho2 (Cat. <I/259>) with coordinates of 2838666 stars taken from UCAC2 (Herald, 2003); UCAC2 (Zacharias et al., 2003, Cat. <I/289>) with 16356096 stars between 12.00 and 14.99mag to the north from -45{deg} declination. Predictions were made for 17 largest numbered transneptunian asteroids and 4 known binary Kuiper Belt objects. 67 events occuring at solar elongation of 30{deg} and more are selected. Observations of these occultations by all available means are extremely important since they can give unique information about the size of TNOs and improve their orbits dramatically. Finder charts and preliminary path plots are available separately at http://hea.iki.rssi.ru/~denis/TNOocc.html of by E-mail to denis@hea.iki.rssi.ru
- ID:
- ivo://CDS.VizieR/J/AJ/146/12
- Title:
- Occultations through Saturn's C ring
- Short Name:
- J/AJ/146/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Saturn's C ring contains multiple spiral patterns that appear to be density waves driven by periodic gravitational perturbations. In other parts of Saturn's rings, such waves are generated by Lindblad resonances with Saturn's various moons, but most of the wave-like C-ring features are not situated near any strong resonance with any known moon. Using stellar occultation data obtained by the Visual and Infrared Mapping Spectrometer on board the Cassini spacecraft, we investigate the origin of six unidentified C-ring waves located between 80900 and 87200km from Saturn's center. By measuring differences in the waves' phases among the different occultations, we are able to determine both the number of arms in each spiral pattern and the speeds at which these patterns rotate around the planet. We find that all six of these waves have between two and four arms and pattern speeds between 1660{deg}/day and 1861{deg}/day. These speeds are too large to be attributed to any satellite resonance. Instead, they are comparable to the predicted pattern speeds of waves generated by low-order normal-mode oscillations within the planet. The precise pattern speeds associated with these waves should therefore provide strong constraints on Saturn's internal structure. Furthermore, we identify multiple waves with the same number of arms and very similar pattern speeds, indicating that multiple m=3 and m=2 sectoral (l=m) modes may exist within the planet.
- ID:
- ivo://CDS.VizieR/J/A+A/515/A32
- Title:
- Pluto, Charon, Nix, Hydra occultations 2008-15
- Short Name:
- J/A+A/515/A32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We made the astrometry of 110GB of images with the Platform for Reduction of Astronomical Images Automatically (PRAIA). By relatively simple astrometric techniques, we treated the overlapping observations and derived a field distortion pattern for the WFI mosaic of CCDs to within 50mas precision. Positions were obtained in the UCAC2 frame with errors of 50mas for stars up to magnitude R=19, and 25mas up to R=17. New stellar proper motions were also determined with 2MASS and the USNO B1.0 catalog positions as first epoch. The catalog contains 2.24 million stars with proper motions, covering Pluto's sky path with 30 arcmin width. Its magnitude completeness is about R=18 with a limit about R=21. The catalog of star positions along Pluto's 2008-2015 sky path was built in the context of the investigation of Pluto and its satellites, aiming to support precise astrometric predictions for stellar occultations by Pluto, Charon, Hydra and Nix for the period 2008-2015. For that, we have carried out in 2007 an observational program at the ESO2p2/WFI instrument covering the sky path of Pluto from 2008 to 2015. We highlight the usefulness of this catalog as a reference frame for star/body astrometric follow-up before and after future stellar occultations involving the Pluto system. In this way, updates for the ephemeris offsets of these bodies and for the position of star candidates for occultations can be enhanced. Besides, the catalog also furnishes useful photometric information for field stars in the flux calibration of observed light curves. The prediction tables of stellar occultations by Pluto, Charon, Nix and Hydra for 2008-2015 were built for investigating the physical properties of Pluto and its satellites, for understanding in a broader sense transneptunian objects - keystones in the study of structure, origin and evolution of the Solar System. Our aim was to derive precise, astrometric predictions. We then constructed an astrometric star catalog in the UCAC2 system covering Pluto's sky path. For that, we have carried out in 2007 an observational program at the ESO2p2/WFI instrument covering the sky path of Pluto from 2008 to 2015. Based on the past 2005-8 occultations successfully predicted, recorded and fitted, a linear drift with time in declination with regard to DE418/plu017 ephemerides was determined for Pluto and used in the current predictions. For offset (mas)=A(t(yr)-2005.0)+B, we find A=+30.5+/-4.3mas/yr and B=-31.5+/-11.3mas, with standard deviation of 14.4mas for the offsets. For these past occultations, predictions and follow-up observations were made with the 0.6m and 1.6m telescopes at the Laboratorio Nacional de Astrofisica/Brazil. No ephemeris correction was applied for right ascension. Although an oscillation pattern related to an error in Pluto's heliocentric distance (geocentric parallax error) cannot be ruled out, none of the attempted models for this scenario could fit the more dispersed right ascension ephemeris offsets derived from the studied past occultations, at least not well below 50mas, in contrast with the standard deviation of only 14.4mas achieved for declination. The candidate stars listed in the prediction tables were searched using a proximity radius of 335mas with the geocentric apparent orbit (corrected by ephemeris offsets) of the body considered. This radius is about the apparent radius of Pluto (50mas) plus the apparent Earth radius (285mas) as projected in the sky plane at 31AU (Pluto-Earth distance for 2008-2015). No threshold in R magnitude was used in the search for candidates. Pluto is crossing interstellar clouds, so relatively faint R objects may turn out to be bright infrared stars, perfect targets for the SOFIA observatory and for ground-based instruments well equipped with H, J or K band detectors (H, J and K magnitudes are promptly available in the tables if the star belongs to the 2MASS). Besides, events may be also favored by slow shadow speeds of less than 20km/s. Also, no constraint on a geographic place was applied, as in principle SOFIA observations can be done from any sub-solar point on Earth. Events in daylight at sub-planet point were not excluded either, as they could yet be observable in the dark, right above the horizon, from places near the Earth terminator. We furnish here prediction tables for future and also for past stellar occultations covering the sky path by Pluto between 2008-2015. The importance of predictions for occultations still to come is obvious. But the predictions of past occultations are also useful for at least three reasons. First, they can be used by anyone as reference for ongoing fittings of light curves of recent past observed events. Second, they serve to derive ephemeris drifts by comparing expected and observed central instants and C/A values. Finally, they can be used as an external check for the accuracy and precision of our prediction tables. In a general sense, assuming a bulk error of 30mas for C/A from the estimated errors of the catalog star positions and from the errors of the derived ephemeris offsets, we can state that the shadow path uncertainties over Earth are on the order of less than 800km for the stellar occultation predictions of Pluto and Charon. Considering orbital issues and the smaller sizes of Nix and Hydra, the probability of success quoted for these two satellites are about 10-25%. This is not as high as hoped, but not despairingly small, especially if the event occurs above a dense, populated region in terms of astronomers, including amateurs.
- ID:
- ivo://CDS.VizieR/J/A+A/541/A142
- Title:
- Prediction of stellar occultations 2008-2015
- Short Name:
- J/A+A/541/A142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The prediction tables of stellar occultations by Eris, Haumea, Makemake, Quaoar, Orcus, Sedna, Varuna, Ixion, 2002TX300 and 2003AZ84 for 2008-2015 were built to support the investigation of the physical properties of large transneptunian objects - keystones in the study of structure, origin and evolution of the Solar System. Our goal was to derive precise, astrometric predictions. With this aim, we constructed astrometric star catalogs in the UCAC2 system covering their sky paths. For that, we have carried out in 2007-2009 an observational program at the ESO2p2/WFI instrument covering the sky path of these 10 large TNOs for the 2008-2015. We made the astrometry of 316 GB of images with the Platform for Reduction of Astronomical Images Automatically (PRAIA). By relatively simple astrometric techniques, we treated the overlapping observations and derived a field distortion pattern for the WFI mosaic of CCDs to within 50 mas precision. The catalog star positions were obtained in the UCAC2 frame with errors of 40mas for stars up to magnitude completeness (about R=19). New stellar proper motions were also determined with 2MASS and the USNO B1.0 catalog positions as first epoch. The catalogs of all TNOs contain in all more than 5.35 million stars with proper motions, covering the sky paths of the objects with 30 arcmin width. The magnitude completeness is about R=19 with a limit about R=21. Ephemeris offsets with about 50mas to 100mas precision were applied for each TNO orbit to improve the predictions. They were obtained during 2007-2010 from a parallel observational campaign carried out with 0.6m to 2.2m size telescopes. The 2718 candidate stars listed in the prediction tables were searched using a proximity radius of 335mas with the geocentric apparent orbit (corrected by ephemeris offsets) of the body considered. This radius is about the apparent radius of a body with Pluto's size (50mas) plus the apparent Earth radius (285mas) as projected in the sky plane at 31AU (about the Pluto-Earth distance for 2008-2015). No threshold in R magnitude was used in the search for candidates, as relatively faint R objects may turn out to be bright infrared stars, perfect targets for the SOFIA observatory and for ground-based instruments well equipped with H, J or K band detectors (H, J and K magnitudes are promptly available in the tables if the star belongs to the 2MASS). Besides, events may be also favored by slow shadow speeds of less than 20km/s. Also, no constraint on a geographic place was applied, as in principle SOFIA observations can be done from any sub-solar point on Earth. Events in daylight at sub-planet point were not excluded either, as they could yet be observable in the dark, right above the horizon, from places near the Earth terminator. We furnish here prediction tables for future and also for past stellar occultations covering the sky paths between 2008-2015. The importance of predictions for occultations still to come is obvious. But the predictions of past occultations are also useful for at least three reasons. First, they can be used by anyone as reference for ongoing fittings of light curves of recent past observed events. Second, they serve to derive ephemeris drifts by comparing expected and observed central instants and C/A values. Finally, they can be used as an external check for the accuracy and precision of our prediction tables. In all, for R=19 stars (catalog magnitude completeness) and 40mas errors in the WFI positions, we may assume a bulk error of about 80mas for C/A, dominated by the ephemeris offsets errors of about 70mas. For about 40AU, this implies a shadow path uncertainty over the Earth of the order of 2300km. If the ephemeris offsets can be well determined to within 30mas precision, then a bulk error of 50mas in C/A can be achieved, leading to a precision of about 1400km for the WFI occultation path predictions. Thus, the probability of actually observing the occultation is not as high as hoped, but not despairingly small, especially if the event occurs above a dense, populated region in terms of astronomers, including amateurs.
- ID:
- ivo://CDS.VizieR/J/A+A/561/A37
- Title:
- Prediction of stellar occultations 2012.5-2014
- Short Name:
- J/A+A/561/A37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The prediction tables of stellar occultations by 5 Centaurs and 34 TNOs (referred simply as TNOs hereafter) for the period 2012.5-2014 were built to support the investigation of the physical properties of (8405) Asbolus, (24835) 1995 SM55, (10199) Chariklo, (26375) 1999 DE9, (47171) 1999 TC36, (38628) Huya, (54598) Bienor, (55565) 2002 AW197, (55576) Amycus, (83982) Crantor, (119951) 2002 KX14, (307261) 2002 MS4, (84522) 2002 TC302, (55637) 2002 UX25, (55638) 2002 VE95, (119979) 2002 WC19, (120132) 2003 FY128, (174567) 2003 MW12, (120178) 2003 OP32, 2003 UZ413, (84922) 2003 VS2, (90568) 2004 GV9, 2004 NT33, (175113) 2004 PF115, (120347) Salacia, (120348) 2004 TY364, (144897) 2004 UX10, 2005 CC79 (2011 FX62), (303775) 2005 QU182, (145451) 2005 RM43, (145452) 2005 RN43, (145453) 2005 RR43, (202421) 2005 UQ513, 2007 JH43, (278361) 2007 JJ43, (225088) 2007 OR10, (229762) 2007 UK126, 2008 OG19, and 2010 EK139 for this period. These objects are important to understand the structure, origin, and evolution of the outer solar system. Our goal was to derive precise predictions. With this aim, we constructed astrometric star catalogues in the UCAC4 system covering their sky paths. For that, we carried out during 2011-2013 an observational program at the ESO2p2/WFI instrument covering the sky path of these 39 TNOs for the period 2012.5-2014. We made the astrometry of 550 GB of images with the Platform for Reduction of Astronomical Images Automatically (PRAIA). By relatively simple astrometric techniques, we treated the overlapping observations and derived a field distortion pattern for the WFI mosaic of CCDs to within 50mas precision. The catalogue star positions were obtained in the UCAC4 frame with uncertainties of 40mas for stars up to magnitude completeness (about R=19). New stellar proper motions were also determined with 2MASS and the USNO B1.0 catalogue positions as first epoch. The catalogues for all TNOs contain in all more than 12.4 million entries, covering the sky paths of the objects with 30 arcmin width. The magnitude completeness is about R=19 with a limit about R=21. Ephemeris offsets with about 10mas to 100mas precision were applied for each TNO orbit to improve the predictions. They were obtained during 2011-2013 from a parallel observational campaign carried out with telescope diameters from 0.6m to 2.2m. The 7343 candidate stars listed in the prediction tables were searched using a proximity radius of 650mas with the geocentric apparent orbit (corrected by ephemeris offsets) of the body considered. This radius is a little more than seven times the apparent radius of a body with Pluto's size (50mas) plus the apparent Earth radius (285 mas) as projected in the sky plane at 31AU (about the Pluto-Earth distance for 2008-2015). No threshold in R magnitude was used in the search for candidates, as relatively faint R objects may turn out to be bright infrared stars, perfect targets for the SOFIA observatory and for ground-based instruments well equipped with J, H, or K band detectors (J, H, and K magnitudes are promptly available in the tables if the star belongs to the 2MASS). Besides, events may be also favoured by slow shadow speeds of less than 20km/s. Also, no constraint on a geographic place was applied, as in principle SOFIA observations can be done from any sub-solar point on Earth. Events in daylight at sub-planet point were not excluded either, as they could yet be observable in the dark, right above the horizon, from places near the Earth terminator. We furnish here prediction tables for future and also for past stellar occultations covering the sky paths between 2012.5-2014. The importance of predictions for occultations still to come is obvious. But the predictions of past occultations are also useful for at least three reasons. First, they can be used by anyone as reference for ongoing fittings of light curves of recent past observed events. Second, they serve to derive ephemeris drifts by comparing expected and observed central instants and C/A values. Finally, they can be used as an external check for the accuracy and precision of our prediction tables. In all, for R=19 stars (catalogue magnitude completeness) and 40mas errors in the WFI positions, we may assume a bulk error of about 80mas for C/A, dominated by the ephemeris offsets errors of about 70mas. For about 40AU, this implies a shadow path uncertainty over the Earth of the order of 2300km. If the ephemeris offsets can be well determined to within 30mas precision, then a bulk error of 50mas in C/A can be achieved, leading to a precision of about 1400km for the WFI occultation path predictions. Thus, the probability of actually observing the occultation is not as high as hoped, but not despairingly small, especially if the event occurs above a dense, populated region in terms of astronomers, including amateurs, with access to telescopes.
- ID:
- ivo://CDS.VizieR/J/A+AS/139/47
- Title:
- 1995 Saturnian satellites mutual events
- Short Name:
- J/A+AS/139/47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The files contain the results of Photometry and Position Observations of Saturnian Satellites. Some file presents a specific data of each measurement. Common parameters of observations such as the initial moment are given in the article.
- ID:
- ivo://CDS.VizieR/J/A+A/544/A29
- Title:
- 2009 Saturnian satellites mutual events
- Short Name:
- J/A+A/544/A29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The photometry of mutual occultations and eclipses of natural planetary satellites can be used to infer very accurate astrometric data. This can be achieved by processing the light curves of the satellites observed during international campaigns of photometric observations of these mutual events. This work focuses on processing the complete database of photometric observations of the mutual occultations and eclipses of the Saturnian satellites made during the international campaign in 2009. The final goal is to derive new accurate astrometric data.
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