Meniscus Telescope Research Articles

R Band Photometry of X-Ray Selected BL Lacertae Objects: 1ES 0229+20, 1ES 0323+02, 1ES 0502+67, 1ES 0647+25, 1ES 0806+52, 1ES 0927+50, 1ES 1028+51, 1ES 1959+65 and 1ES 2344+51

We present optical R band photometry for nine X-ray Einstein Slew Survey Sample BL Lacertae objects: 1ES 0323+022, 1ES 0502+675, 1ES 0647+250, 1ES 0806+524, 1ES 1028+511, 1ES 1959+650 and 1ES 2344+514. Two blazars 1ES 0229+200 and 1ES 0927+500 didn't show any detectable variability. They have all been observed with the ST-6 CCD camera attached to the Newtonian focus of the 70-cm meniscus telescope. These data provide optical information on sources that have been rarely observed in the optical band. Variability on long time scales within one magnitude in R band was detected for all of the observed objects except two. The largest variation was observed for 1ES 0502+675 and equals to ΔR=1 m . 07.

CCD photometry of blazars at Abastumani Observatory

Abstract We give a brief summary of the ongoing Abastumani Active Galactic Nuclei Monitoring Program, started in May of 1997. More than 75000 frames were obtained during more than 900 nights of observation for about 50 target objects, among them X-ray, γ-ray and optical blazars. All observations were done in the BVRI bands using the ST-6 CCD based Photometer attached to the Newtonian focus of the 70-cm meniscus telescope. Image reductions have been done using DaophotII. The lightcurves illustrating the activity of selected blazars in R band, namely AO 0235+164 and S4 0954+658 are presented. Most of the objects under study show light variations in optical bands over one magnitude. The largest variation was observed for AO 0235+116 - 4 m . 0 in R band.

Optical behaviour of BL Lacertae during 1997-2001: long-term, intraday and intrahour variability

Abstract We present the results of optical observations of BL Lacertae from August 1997 to November 2001 carried out with ST-6 CCD Camera attached to the Newtonian focus of the 70-cm meniscus telescope of Abastumani Observatory. The long-term, intraday and intrahour variabilities of BL Lacertae were studied on the bases of 317 and 259 nights, respectively. The variability pattern shown by BL Lacertae is very complex. The maximum amplitude of the long-term variability in the B band equals 3m.0 (rms=0.03). The variation in the V and R bands are within 2m.71 (0.02) and m.53 (0.01), respectively. This means that variations are larger at shorter wavelength or the object become bluer in the active phase. It were also demonstrated that BL Lacertae shows intraday variability within 0.30 (0.02), while intrahour variability within 0.10 (0.01) magnitudes.

BVRICHARGE-COUPLED DEVICE PHOTOMETRY OF ACTIVE GALACTIC NUCLEI AT ABASTUMANI OBSERVATORY

We give a brief summary of the ongoing Abastumani active galactic nuclei monitoring programme started in May 1997. More than 65000 frames have been obtained during observations of about 50 target objects, among them X-ray, ?-ray and optical blazars, for more than 700 nights. All observations were made in the BVRI bands using an ST-6 charge-coupled device photometer attached to the Newtonian focus of a 70 cm meniscus telescope. Image reductions have been performed using image reduction packages Daophot II. The light curves illustrating the activity of selected blazars in R band, namely 3C 66A and AO 0235 + 164, are presented. Most objects under study show light variations in the optical band over one magnitude. The largest was observed for AO 0235 + 116, of magnitude 4.0 in the R band.

BL LACERTAE: LONG-TERM, INTRADAY AND INTRAHOUR VARIABILITY

We present preliminary results of the optical observations of BL Lacertae during the period June-November 2001 carried out using an ST-6 charge-coupled device camera attached to the Newtonian focus of the 70 cm meniscus telescope of the Abastumani Observatory. The aim of these observations is to study the long-term variability, intranight variability and intrahour variability of BL Lacertae. The overall long-term variation in the R band has a magnitude of 1.80 (rms, 0.03). We also demonstrated that the typical average amplitudes of the intraday variability and the intrahour variability in the R band are of magnitudes 0.30 ± 0.02 and 0.10 ± 0.01 respectively. The maximum amplitudes of both types of variation are of magnitude 0.40 ± 0.02.

Investigation of Nova Cygni 1975 (V 1500) at Abastumani. I. Photographic Observations of Spectra

On the night of August 30/31, 1975, one of the authors discovered a nova in the constellation Cygnus. Spectroscopic observations of the nova were made with a 70-cm meniscus telescope, using a 72-cm, 8°, objective prism and a diffraction spectrograph mounted at the Cassegrain focus. The radial velocity of expansion of the nova's shell turned out to be about 2000 km/sec and its mass was on the order of 10-5 M ⊙ and had a tendency to increase with time; we estimated the emission energy to be 5·1044 erg and the kinetic energy of the shell to be 1045 erg, while the electron temperature in the shell is 5000 K.

Toward the Monitoring of Blazars at Abastumani

We give a brief summary of the ongoing Abastumani Blazar Monitoring Program (ABMP) started in May 1997. More than ~50,000 frames of data have been collected during 370 nights of observations on about 50 target objects. Preliminary results of two years of monitoring of ten selected AGNs carried out in the framework of ABMP are presented. All observations were done in the BVRI bands using the CCD ST-6 based photometer attached to the 70-cm meniscus telescope's Newtonian focus. Image reductions were made using different software packages of image reduction systems such as IRAF, MIDAS and STARLINK. All objects under study show light variations exceeding one magnitude. The largest variation was observed for AO 0235+116, amounting to 4.0 mag in the R band.

Spectrophotometry of the nucleus of the galaxy ngc 4151 in 1988

Abstract Spectrophotometric observations of the nucleus of the galaxy NGC 4151, the reference star and spectrophotometric standards were carried out at the Crimean Astrophysical Observatory during 13 nights in 1988 (January 23 – June 10). The slitless spectrograph and the digital TV complex of the 0.5-m meniscus telescope were used. The spectral resolution was 60Å under the condition of good seeing. Energeticaly calibrated monochromatic fluxes with steps of 50Å were obtained for the nucleus in the spectral region of 4500–7000Å. Fluxes in the continuum (5200–5700Å), in the blend 1 (Hβ 4861Å + O[III] 4959+5007Å) and the blend 2 (Hα 6563Å + N[II] 6548+65841Å) were calculated.

Spectrophotometric monitoring of the nucleus of the galaxy NGC 4151 at its light minimum in 1988

Spectrophotometric monitoring of the nucleus of the galaxy NGC 4151 was carried out for 13 nights from 23 January to 10 June 1988 in the wavelength range 4000–7000 A. A 0.5-m meniscus telescope, a slitless spectrograph, and the highly sensitive, digital television complex of the Crimean Astrophysical Observatory were used. The exposure time was 150–300 sec, while the time resolution, allowing for recording spectra of the comparison star, was about 30 min. The results show that the galaxy’s nucleus was in a deep minimum. On a time scale of days to months, the synthetic magnitudes Vsyn and the fluxes Fcon in the continuum had a similar time dependence; the amplitude of variability reached 15% in January-April, while a brightness increase of 30% was recorded on 13 and 14 May. The time variations of the fluxes in the first (Hβ + [O III] 4959 A + 5007 A) and second (Hα + [NII] 6548 A + 6584 A) blends were different.

Proper motions, absolute magnitudes and spatial distribution of Zirconium stars

AbstractThe computational algorithm to determine the the proper motions of Zirconium stars on the basis of catalogues “Carte du Ciel” and on the recent photographic observations carried out with the 70cm Abastumani meniscus telescope is presented. It allowed to determine the proper motions of 288 stars in the region around α Per with a rms error of ± 0,004 arcsec/yr. Applying the method proper motions of 74 Zirconium stars and 146 control stars have been obtained. The error of proper motions obtained for the North Zone (δ > −2°) 109 AGK3 control stars is ± 0.006 arcsec/yr.On the basis of proper motins absolute magnitudes were separately calculated for the MCLPZS and LASZS.For the MCLPZS the average absolute visual magnitude at maximum, corresponding to the mean period of P = 350 days, equals −3ϕm.9. For the LASZS the mean absolute visual magnitude, corresponding to the apparent median ones equals −1ϕm.9. Low luminosity (Mv = −1ϕmϕ9) Zirconium stars escape rather far (at a distance of up to 2 kpc) to the South from the Galactic plane into the region l ∼ 240 – 260°, where its assumed to be a connection with the Large Magellanic Cloud (LMC) begins to appear. Low luminosity Zirconium stars are weakly correlated with position of the Galaxy spiral arms. The MCLPZS show a somewhat other distribution.

Observatory Fades Away in Splendid Isolation

Abastumani, Georgia—the former Soviet Union's first mountaintop observatory—once did pioneering studies of the Crab Nebula and, with an array of telescopes that includes a 40-centimeter refractor and a 70-centimeter meniscus telescope, discovered more than a dozen supernovas. Today, like most scientific institutions in Georgia, it is fighting for survival. During the winter months, with just 4 hours of electricity a day, room temperatures approach freezing and Abastumani's scientists analyze old data in front of gas stoves in their apartments. Telescopes and support equipment are turned on only for maintenance.

First Results for CCD Observations with the 70 cm Meniscus Telescope

AbstractFrom the middle of 1993, a ST-6 CCD Camera (375 × 242 array with 23 × 27 microns pixel size) was mounted at the Newtonian focus (f/3) of the 70 cm meniscus telescope of the Abastumani Observatory. The photometer is now equipped with various sets of narrow-band interference, intermediate and wide band standard niters. Some pilot observations were carried out in direct imaging mode and in combination with an 8° objective prism (166 Å mm−1 at Hγ). Spectrophotometric standard stars with absolute calibrations were observed in the 8° mode to determine the CCD spectral response. Some other observations were performed with a prism-interference filter combination to estimate the observational mode efficiency.

The Stellar Structure of the Orion Spiral ARM in Selected Directions. I. The Galactic Anticenter

To investigate the spatial distribution of various stellar groups in the Hertzsprung-Russell diagram, it is necessary to have homogeneous observational data of MK spectral classification and photometry. This enables us to perform some statistical analyses with sufficient accuracy.This paper reports BV photographic photometry of about 700 stars complete to mV = 12, in the direction of galactic anticenter with (l,b) = (169°, −12.4°), (178°, −2.4°), (184°, 8.9°). For the MK spectral data we used the catalogue by Bartaya and Kharadze (1992), which contains spectral and luminosity classes of 6042 stars in Kapteyn Areas Nos. 44–67. The observational data for this catalogue were obtained using the Abastumani Astrophysical Observatory 70 cm meniscus telescope and an 8°objective prism with dispersion 166 Åmm−1 near Hγ. The errors in classification are equal to ± 0.6 spectral subclasses and ± 0.5 luminosity classes, with a limiting magnitude of mV = 12.5.

A Deep Spectral Survey of Peculiar A-Type Stars

AbstractWe are conducting a long-term deep spectral survey to investigate the distribution of Ap and Am stars in selected fields of the Milky Way and in open star clusters of different ages. The spectral survey is based on objective prism spectra obtained with an eight degree prism attached to the 70/98 cm meniscus telescope (f/3, 135 Å mm−1at Hδ) at the Abastumani Observatory. Kodak IIIa-J emulsions hypersensitized by baking in nitrogen gas are used in combination with a 500 Å FWHM filter centered on Hδ. A limiting magnitude ofmB= 14 was reached in an exposure time of 120 m. Study of the objective prism plates is still in a very early stage. Observations of the central part of the same field taken with a CCD resulted in a limiting magnitudemB= 16. On the basis of spectral material obtained, a wide range of spectra may be classified in the MK system.

Recent Developments in the Work on Automated Spectral Classification by Means of Objective Prism Spectra

Some years ago a complex programme of studying the main meridional section of the Galaxy was started by astronomers of Kiev, Tartu, Abastumani and Vilnius Observatories with the aim of improving our knowledge of spatial and kinematic characteristics of stellar populations. Characteristic to the programme is the use of absolute proper motions of stars together with automated quantitative spectral classification for large stellar-statistical samples. The data are gathered in areas lying within 30° of the main meridional section of the Galaxy. To classify stars, objective prism stellar spectra of intermediate dispersion (166 å/mm at Hγ), obtained with the 70 cm meniscus telescope at the Abastumani Astrophysical Observatory, are used. The field diameter is 4° 50′, and the limiting photographical stellar magnitude is about 12 m . Our system of automated quantitative spectral classification of F-K stars applies criteria evaluation and is mainly based on two software packages: the SDR package for spectrometric data reduction and the CTATEC-2 package determining the linear regression model used for classification (Malyuto & Shvelidze 1989; Malyuto, Pelt & Shvelidze 1993).

A Deep Visual-Red and Near Infrared Objective Prism Spectral Survey of the Milky Way

The deep visual-red and near infrared low dispersion (1250 Å/mm at Hɤ and 7000 A/mm at Å band) objective prism spectral survey of the Milky Way equatorial ten degree belt has been done by 70 cm meniscus telescope equipped with 2° prism (30° < 1 < 115° infrared).

Television observations of Martian cloud formations in 1973: Preliminary results

During the period July 14–September 11, 1973, about 25 000 television pictures of Mars were obtained using a 0.7m telescope in ten spectral regions. A dust storm in moderate latitudes was recorded. It started before Mars passed perigee. During the observation period the atmosphere was gradually clearing. About 3000 pictures of Mars were taken using a 0.5m meniscus telescope during the period of Nobember 19, 1973–February 19, 1974. On November 19 the atmosphere was very hazy and heavy dust clouds were recorded. The second dust storm cleared during December through January.

Ultraviolet spectra of Capella

IN December 1973, during observations from the space observatory Orion 2 on Soyuz 13, three spectrograms of Capella (α Aur, GO III, mv=0.2) were obtained in the wavelength region 2,000–3,000 A. The spectrograms were made by a wide-angle meniscus telescope of the Cassesgrain system, with an aperture diameter of 240 mm, an equivalent focal length of 1,000 mm, and a 4-grade quartz prism objective. The dispersion of the spectrograph was 170, 280 and 550 A mm−1, at wavelengths of 2,000, 2,500 and 3,000 A, respectively.

Dependence of Flare Decay Rates on Flare Luminosities for UV Cet Stars

ON the descendent branch of typical light curves of UV Cet-type star flares one can usually distinguish a fast decay stage (I) that begins just after flare maximum and a following slow decay stage (II)1,2. The dependences of flare decay rates for both stages on flare luminosities at maxima have been studied in ref. 3. We have analysed observations of 13 UV Cet flare stars made at the Crimean Astrophysical Observatory during 1969–1972 with the 64 cm meniscus telescope, in a photometric system close to B. Only flare light curves obtained with certainty have been used in this study.

The Peculiar Stars and Spectral Classification

The spectral classification experiments with the 70-cm meniscus telescope and 8° objective prism of Abastumani Observatory (dispersion 166 Å mm-1) have shown that if we apply the Kodak IIa-O plates at the 0.4 mm widening of spectra and the 20 minutes exposure time, we can successfully classify with relatively high accuracy in two dimensional MK system the stars down to the 11th magnitude, with simultaneous discrimination of peculiars.We have undertaken such determinations first of all in Kapteyn Selected Areas aiming to fill the gaps in existing data for these standard areas.Finally we could mention the high quality of the meniscus telescope optics together with good seeing in Abastumani as favourable factors making the Abastumani spectra of 10–11th magn. stars comparable with the slit spectra of the same dispersion.The Abastumani spectra allow to apply the Morgan and Kitt-Peak criteria of MK classification only with a slight modification.We have two-dimensionally classified in MK system about ten thousand stars down to the 11th magnitude in KA Nos. 2–43 (4.°5 × 4°5 each). Among them 137 peculiar stars have been revealed. They are mainly Ap, Am and BaII (7 stars) and the stars with composed spectra (5). 97 stars have been first identified as peculiars.