Automatic Telescope Research Articles

Two-site orbit determination: The 2003 GEO observation campaign from Collepardo and Mallorca

In September 2003 the Group of Astrodynamics of the University of Rome “La Sapienza” (GAUSS) carried out a two-site optical observation campaign addressed to the orbit determination of objects in the geosynchronous region without a priori information. Two 40 cm aperture Ritchey-Chrétien telescopes were employed: the f/7.5 “Collepardo Automatic Telescope” (CAT, located in Collepardo, Italy) and an f/5 tube of the “Observatori Astronòmic de Mallorca” (OAM, located in Mallorca, Spain). The baseline between the sites is about 1000 km. Three second long, 1 min apart exposures were simultaneously taken in sidereal tracking mode, looking at the same arcs of the geosynchronous ring. The size of the fields of view allowed to see a few satellites in two successive frames from both sites. The Lambert theorem has been exploited to determine the orbits, averaging the data with the least square method in the case that more than 2 points were available. Of course, the longer the time interval between the positions, the lower the effect of measuring errors. Nevertheless, the only way to have quite distant points would be tracking the satellite, but following-up is typically time demanding thus not suitable for a surveillance campaign, hence not very interesting from a practical standpoint. In the paper the results of the orbit determination from the September 2003 campaign are reported. More in detail, the outcomes of some classical methods for solving the Lambert theorem, are compared with solutions based on the measurements fitted with the least squares method, with the circular orbit assumption results, with the one-site complete orbit determination and with the TLEs.

HD 8801: A Unique Single Am Star with γ Doradus and δ Scuti Pulsations

We have discovered the first example of a star pulsating intrinsically with both γ Doradus and δ Scuti frequencies. The star, HD 8801, is an Am metallic-line star that appears to be single. Since the vast majority of Am stars are members of binary systems with periods less than 1000 days and also do not pulsate, HD 8801 possesses a very unusual, if not unique, combination of physical properties. Our photometry, acquired with an automatic telescope at Fairborn Observatory, resolves six independent pulsation periods between 0.048 and 0.404 days. The two longest periods lie within the range of γ Dor variables, while the four shorter periods are within the range of δ Sct stars. Eleven radial velocities, obtained over an 11 month period, have a mean of 0.8 ± 0.3 km s-1, providing no evidence for a spectroscopic companion. The star is on the main sequence and lies within both the γ Dor and δ Sct instability strips. Pulsation constants computed for the six periods agree with pulsation constants computed for other γ Dor and δ Sct variables. HD 8801 is also the first confirmed case of a metallic-line star pulsating with γ Dor frequencies. Its projected rotational velocity of 55 km s-1 is typical for Am stars, which, as a group, rotate more slowly than normal A stars. HD 8801's slow rotation compared to normal A stars does not appear to arise from either a binary companion or evolutionary expansion and thus remains a puzzle. The coexistence of metallicism and pulsation in several main-sequence stars near the red edge of the δ Sct strip contradicts recent models that predict pulsations only in more evolved stars.

Five New Extrasolar Planets

We report multiple Doppler measurements of five nearby FGK main-sequence stars and subgiants obtained during the past 4-6 yr at the Keck Observatory. These stars, namely, HD 183263, HD 117207, HD 188015, HD 45350, and HD 99492, all exhibit coherent variations in their Doppler shifts consistent with a planet in Keplerian motion. The five new planets occupy known realms of planetary parameter space, including a wide range of orbital eccentricities, e = 0-0.78, and semimajor axes, 0.1-3.8 AU, that provide further statistical information about the true distributions of various properties of planetary systems. One of the planets, HD 99492b, has a low minimum mass of 0.112M_(Jup) = 36M_(Earth). Four of the five planets orbit beyond 1 AU. We describe two quantitative tests of the false alarm probability for Keplerian interpretations of measured velocities. The more robust of these involves Monte Carlo realizations of scrambled velocities as a proxy for noise. Keplerian orbital fits to that noise yield the distribution of χ^2_v to compare with χ^2_v from the original (unscrambled) velocities. We establish a 1% false alarm probability as the criterion for candidate planets. All five of these planet-bearing stars are metal-rich, with [Fe/H] > +0.27, reinforcing the strong correlation between planet occurrence and metallicity. From the full sample of 1330 stars monitored at Keck, Lick, and the Anglo-Australian Telescope, the shortest orbital period for any planet is 2.64 days, showing that shorter periods occur less frequently than 0.1% in the solar neighborhood. Photometric observations were acquired for four of the five host stars with an automatic telescope at Fairborn Observatory. The lack of brightness variations in phase with the radial velocities supports planetary-reflex motion as the cause of the velocity variations. No transits were observed, but their occurrence is not ruled out by our observations.

JISCO: Jovian Interferometric Seismometer at Concordia Observatory

Seismology is the only way to investigate the internal structure of the giant planets, with a lot of scientific implications such as high pressure physics and huge constraints on the scenario of solar system formation. As compared to other existing possibilities (ground based network, spacecraft), seismology of Jupiter will take a maximum benefit from the peculiarities of the Concordia station as an astronomical observatory. Indeed, the continuous temporal coverage for all the winter season, and the quality of the atmospheric seeing, are crucial parameters for this program. The jovian seismometer SYMPA, already used for network observations, is perfectly suitable for Dome C conditions. With the already existing small telescopes deployed in the frame of site testing program, seismology of Jupiter will constitute a excellent intermediate project with high scientific return, before the installation of large telescopes. In a second step, such an instrument could be a first light instrument for a 1.5 m class automatic telescope, which is to be developed as an individual stone for a large interferometer. With this diameter, the same scientific program on Saturn could also be achieved.

Hands-on-Universe, Europe Bringing frontline interactive astronomy to the classroom

Hands-on-Universe, Europe (EU-HOU) aims at re-awakening the interest for science in the young generations through astronomy and new technologies. It relies on real observations acquired through a worldwide internet-based network of automatic telescopes or with didactical tools (webcam, radiotelescope). Pupils manipulate images in the classroom environment, using specific software within pedagogical resources constructed in close collaboration between researchers and teachers. EU-HOU is freely available on the web, and trains european teachers.

Unsolved problems in observational astronomy. I. Focus on stellar spectroscopy

AbstractWe present the highlights of current observational programs in stellar optical spectroscopy carried out with 8‐10 m class telescopes as well as with smaller telescopes. Topics discussed include: 1. light elements abundances and their cosmological implications; 2. search for Population III stars and spectroscopy of extremely metal deficient stars; 3. abundances of different stellar populations in the Galaxy; 4. spectroscopy of resolved stars in Local Group galaxies; 5. Li and Be abundances and internal mixing in stars; 6. spectroscopy of very‐low mass stars and brown dwarfs; 7. radial velocity search of extrasolar planets; 8. stellar oscillations and asteroseismology; 9. stellar magnetic activity and Doppler imaging of stellar surface features. We also highlight the role that dedicated 1‐2 m automatic telescopes with spectroscopic capabilities can play in several fields of stellar optical spectroscopy. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

ATOM – an Automatic Telescope for Optical Monitoring

Astronomische NachrichtenVolume 325, Issue 6-8 p. 659-659 Original Paper ATOM – an Automatic Telescope for Optical Monitoring M. Hauser, M. Hauser [email protected] Search for more papers by this authorC. Möllenhoff, C. Möllenhoff Landessternwarte Heidelberg-Königstuhl, Königstuhl 12, 69117 Heidelberg, GermanySearch for more papers by this authorG. Pühlhofer, G. Pühlhofer Landessternwarte Heidelberg-Königstuhl, Königstuhl 12, 69117 Heidelberg, GermanySearch for more papers by this authorS. J. Wagner, S. J. Wagner Landessternwarte Heidelberg-Königstuhl, Königstuhl 12, 69117 Heidelberg, GermanySearch for more papers by this authorH.-J. Hagen, H.-J. Hagen Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, GermanySearch for more papers by this authorM. Knoll, M. Knoll Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, GermanySearch for more papers by this author M. Hauser, M. Hauser [email protected] Search for more papers by this authorC. Möllenhoff, C. Möllenhoff Landessternwarte Heidelberg-Königstuhl, Königstuhl 12, 69117 Heidelberg, GermanySearch for more papers by this authorG. Pühlhofer, G. Pühlhofer Landessternwarte Heidelberg-Königstuhl, Königstuhl 12, 69117 Heidelberg, GermanySearch for more papers by this authorS. J. Wagner, S. J. Wagner Landessternwarte Heidelberg-Königstuhl, Königstuhl 12, 69117 Heidelberg, GermanySearch for more papers by this authorH.-J. Hagen, H.-J. Hagen Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, GermanySearch for more papers by this authorM. Knoll, M. Knoll Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, GermanySearch for more papers by this author First published: 13 October 2004 https://doi.org/10.1002/asna.200410305Citations: 32AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article.Citing Literature Volume325, Issue6-8October 2004Pages 659-659 RelatedInformation

The STELLA robotic observatory

AbstractSTELLA is a robotic observatory with two fully automatic telescopes (STELLA‐I and STELLA‐II) located at the Teide Observatory in Tenerife, Spain. Not only the telescopes are automatic but also the entire observatory, no human presence is needed for observing ‐ not even in remote control. STELLA‐I supports a high‐resolution, fiber‐fed and benchmounted echelle spectrograph and a wide‐field CCD imaging photometer while STELLA‐II feeds a similar but wide‐band imaging photometer and a testbed for prototype adaptive optics for robotic telescopes. The first telescope is scheduled for first light in November 2004, the second telescope for March 2005. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Automatic telescope for observation of near-Earth asteroids

Automatic telescope for observation of near-Earth asteroids

Chromospherically Active Stars. XXI. The Giant, Single-lined Binaries HD 89546 and HD 113816

We have obtained spectroscopy and photometry of the chromospherically active, single-lined spectroscopic binaries HD 89546 and HD 113816. HD 89546 has a circular orbit with a period of 21.3596 days. Its primary has a spectral type of G9 III and is somewhat metal-poor with [Fe/H] ~ -0.5. HD 113816 has an orbit with a period of 23.6546 and a low eccentricity of 0.022. Its mass function is extremely small, 0.0007 M⊙, consistent with a very low inclination. The primary is a slightly metal-poor K2 III. A decade or more of photometric monitoring with an automatic telescope demonstrates that both systems display brightness variations due to rotational modulation of the visibility of photospheric star spots, as well as light-curve changes resulting from the redistribution of star spots by differential rotation and long-term changes in the filling factor of the spots. We determined rotation periods for each season when the observations were numerous enough. Our mean rotation periods of 21.3 and 24.1 days for HD 89546 and HD 113816, respectively, confirm that the giants in each system are synchronously rotating. The orbital elements and properties of the giant components of these two systems, including levels of surface magnetic activity, are quite similar. However, the two rotational inclinations are rather different, 57° for HD 89546 and 13° for HD 113816. Thus the latter giant is seen nearly pole on. We analyzed the light curves for similarities and differences that result from viewing these two systems from quite different inclinations.

Optical Monitoring of bright Blazars with Automatic Telescopes

Well sampled light curves of BL Lac objects are very useful to understand the physical processes responsible for the highly variable emission from this class of AGN. The best way to perform the necessary high number of observations is the use of automatic small aperture telescopes. We present some results of the Perugia-Roma monitoring program concerning the recent active phase of BL Lac and the Intra-Day Variability of S5 0716+714.

Commission 25: Stellar Photometry and Polarimetry: (Photometrie Et Polarimetrie Stellaires)

Technology has continued to influence the methods of stellar photometry and polarimetry in the last triennium. For example, CCDs continue to displace photographic plates in stellar photometry and other detector systems for imaging and spectro-polarimetry, new array detectors for infrared wavelengths have revolutionised the way infrared photometry and polarimetry is done and small automatic telescopes and robotic observatories have experienced a remarkable growth period. The volume of data to be archived and transformed to “standard” systems has become immense and all the problems of inter-comparing different systems still remain.

Monitoring of LPVs with an automatic telescope.

We discuss the possibilities of investigating the semiregular and irregular light change found in evolved late type giant stars with photometric and visually obtained (amateur) data. Period analysis has been done on light curve data from both sources for a sample of semiregular variables. The results are compared to test the ability of visual data to show the frequency contents present in these variables. We nd that both sources of data complete each other, as tting the ne structure visible only in the photometric data needs long-term visual monitoring to guarantee the uniqueness of the t.

Absolute dimensions of solar-type eclipsing binaries.

We present complete uvby light curves of 9 recently discovered eclipsing binaries having late F, G, and K type components within or near the main-sequence band. They are the rst results from a long term program carried out since 1994 at the Stromgren Automatic Telescope at ESO, La Silla. The aim is to provide the accurate absolute dimensions for solar-type stars needed for critical tests of the corresponding theoretical models. A serious dilemma appears to be present in the comparison of predictions from current stellar models with fundamental properties of known 0:7 1:1 M eclipsing binaries (Popper 1997b, Clausen et al. 1999b). Spectroscopic observations of the 9 eclipsing binaries are either available or are being obtained, and detailed analyses of the individual systems will be published in a series of subsequent papers. The light curves were obtained as part of a systematic search for new eclipsing systems among a large sample of (mostly) spectroscopic binaries. Catalogues of the extensive uvby and photometry from this search will be published separately.

On the rotation period of Capella

We present differential Hα and Hβ photometry of the very bright RS CVn-binary α Aurigae (Capella)obtained with theVienna automatic photoelectric telescope in the years 1996 through 2000. Low-level photometric variations of up to 0m.04 are detected in Hα. A multifrequency analysis suggests two real periods of 106 ± 3 days and 8.64 ± 0.09 days, that we interpret to be the rotation periods of the cool and the hot component of the Capella binary, respectively. These periods confirm that the hotter component of Capella rotates asynchronously, while the cooler component appears to be synchronized with the binary motion. The combined Hα data possibly contains an additional period of 80.4 days that we, however, believe is either spurious and was introduced due to seasonal amplitude variations or stems from a time-variable circumbinary mass flow. The rotational periods result in stellar radii of 14.3 ± 4.6 R⊙ and 8.5 ± 0.5 R⊙ for the cool and hot component, respectively, and are in good agreement with previously published radii based on radiometric and interferometric techniques. The long-period eclipsing binary Aurigae served as our check star, and we detected complex light variations outside of eclipse of up to 0m.15 in H α and 0m.20 in Hβ. Our frequency analysis suggests the existence of at least three significant periods of 132, 89, and 73 days. One of our comparison stars (HD 33167, F5V) was discovered to be a very-low amplitude variable with a period of 2.6360 ± 0.0055 days.

The Impact of Light Pollution on a Proposed Automatic Telescope Network (ATN) and Vice Versa

We are proposing to operate a Network of Automatic Telescopes (ATN) for CCD imaging to conduct diverse astrophysical investigations and as a resource for science education. Coordinated utilization of telescopes at diverse sites provides the possibility of obtaining continuous photometry without diurnal interruption. We describe this project and discuss how it is impacted by light pollution, and conversely, how it might mitigate the growth of light pollution.

Flexible Automatic Scheduling for Autonomous Telescopes: The MAJORDOME

We have developped a new method for the scheduling ofastronomical automatic telescopes, in the framework of theautonomous TAROT instrument. The MAJORDOME software canhandle a variety of observations, constrained, periodic,etc., and produces a timeline for the night, which may bemodified at any time to take into account the specificconditions of the night. The MAJORDOME can also handletarget of opportunity observations without delay.

Progress Report for the KAO 1.0 meter Robotic Telescope

AbstractKorea Astronomy Observatory (KAO) is working to rebuild a 1.0-m robotic telescope in collaboration with a company (Astronomical Consultants & Equipment, Inc. or ACE). The telescope is being totally refurbished to make a fully automatic telescope which can operate in both interactive an fully autonomous robotic modes. This paper describes the design concepts and the work completed. The telescope is an f/7.5 Ritchey-Chretien system mounted on an equatorial fork with friction drives capable of high slewing (5°/s2) and high resolution tracking. The control software manages the entire telescope, instruments and observatory. In interactive local and remote modes the observer can manually enter coordinates or retrieve them from a database. In robotic mode the telescope controller downloads requests from users and creates a schedule. The telescope will be equipped with a CCD camera and will be available over the internet.

Search for Transits of a Short-Period, Sub-Saturn Extrasolar Planet Orbiting HD 46375.

Precise brightness measurements of HD 46375 have been acquired with an automatic telescope to search for transits of its short-period, sub-Saturn extrasolar planet. Transits of the companion do not occur, indicating that the inclination of the orbit i is less than 83 degrees and sini is less than 0.992. This upper limit on sini still preserves the possibility that the mass of the planet is less than Saturn's. Analysis of the photometry for HD 46375 reveals no photometric variability larger than 0.0001+/-0.0002 mag at the orbital period of the planet. This effectively eliminates starspots and stellar pulsations as the cause of the radial velocity variations used to infer the planet's existence.

Optical behaviour of markarian 421 during high-energy flares

Abstract In this paper we present the optical behaviour of Mrk 421 from 1992 to April, 1995. The observations were obtained at the Perugia University Observatory with the automatic imaging telescope in the BVR c I c broad-bands. Visual estimates done by “The Astronomer” group and the British Astronomical Association (BAA) are inclosed in the light curve to give a better temporal coverage. During our monitoring the object showed many flares and major outbursts over a large span of temporal scales. From our data there is also a clear correlation between the colour index and the brightness level, which may be due to the thermal contribution of the host galaxy. Furthermore, we found that the X and TeV flares observed in MrK 421 during 1992–1995 are not well correlated with the more intense optical flares. These data, together with the relative stability of the spectral slope during the optical activity, suggest that the optical emission may be related to knots moving in the jet along a helical path.