About Star Photometry on Digitized Astronegatives

Andruk, V. M.; Pakuliak, L. K.; Golovnia, V. V.; Shatokhina, S. V.; Yizhakevych, O. M.; Protsyuk, Yu. I.; Eglitis, I.; Eglīte, M.; Kazantseva, L. V.; Relke, H.; Yuldoshev, Q.; Muminov, M.

doi:10.15407/scine13.01.015

Cited by 8 publications

(7 citation statements)

References 14 publications

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“…In order to extract the coordinates, FWHMs and r magnitude of each object on the plate, we ran the photometric procedure described by Andruk & Villarroel et al (to be submitted). This procedure builds on the methods of Andruk et al (1995Andruk et al ( , 2017Andruk et al ( , 2019 [7][8][9] , and is adapted for POSS-I red emulsions specifically. We also used the procedure to check for other strong transients on the same plate (see Supplementary Information).…”

Section: Methods and Preliminariesmentioning

confidence: 99%

Exploring nine simultaneously occurring transients on April 12th 1950

Villarroel,

Marcy,

Geier

et al. 2021

Preprint

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Nine point sources appeared within half an hour on a region within ∼ 10 arcmin of a red-sensitive photographic plate taken in April 1950 as part of the historic Palomar Sky Survey. All nine sources are absent on both previous and later photographic images, and absent in modern surveys with CCD detectors which go several magnitudes deeper. We present deep CCD images with the 10.4meter Gran Telescopio Canarias (GTC), reaching brightness r ∼ 26 mag, that reveal possible optical counterparts, although these counterparts could equally well be just chance projections.The incidence of transients in the investigated photographic plate is far higher than expected from known detection rates of optical counterparts to e.g. flaring dwarf stars, Fast Radio Bursts (FRBs), Gamma Ray Bursts (GRBs) or microlensing events. One possible explanation is that the plates have been subjected to an unknown type of contamination producing mainly point sources with of varying intensities along with some mechanism of concentration within a radius of ∼ 10 arcmin on the plate. If contamination as an explanation can be fully excluded, another possibility is fast (t < 0.5 s) solar reflections from objects near geosynchronous orbits. An alternative route to confirm the latter scenario is by looking for images from the First Palomar Sky Survey where multiple transients follow a line.

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Section: Methods and Preliminariesmentioning

confidence: 99%

Exploring nine simultaneously occurring transients on April 12th 1950

Villarroel,

Marcy,

Geier

et al. 2021

Preprint

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“…7. Evaluation of photometric instrumental stellar magnitudes m in the system of photoelectric magnitudes B pe [8].…”

Section: Processing Of Digitized Astroplatesmentioning

confidence: 99%

Test of the scanner for expression the astrometric and photometric parameters from the digitized plates

Yuldoshev

Muminov

Andruk

et al. 2022

УФЖ

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This paper performs to research in detail the Epson Expression 10000XL scanner for photographic astroplate archive of the Ulugh Beg Astronomical Institute (UBAI) of the Uzbekistan Academy of Sciences. For processing the astroplates, it is used special developed software in the LINUX/MIDAS/ROMAFOT. The test plate was digitized with grayscale 8 and 16 bits with various scanner resolutions. Astronomical and photometric parameters were carried out from the plate and an evaluation of the developed method accuracy for determining rectangular coordinates and photometry. The repeatability of astrometric and photometric errors of the scanner for the digitized resolutions, 6 successive scans of every plate with a spatial resolution 600, 900, 1200, 1500, 1800, 2100, 2400 and 2540 dpi were processed.

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“…The size of each processed field is ∼13,000 × 13,000 px (1 pixel = 1. ′′ 46) (Protsyuk et al (), Protsyuk et al ()). Conversion of all images from 16‐bit tagged image file (TIF) format to 8‐bit flexible image transport system (FIT) format using the GNU image manipulation program package to reduce file size. Calculation of the flat field and its correction to digitized images. Calculation of rectangular coordinates ( X , Y ) and the instrumental magnitudes m and diameters f (FWHM) for all registered objects on the digitized images by using software in the MIDAS/ROMAFOT environment. Separation of registered objects into two exposures (Andruk et al ()). Creation of a supplementary data file for identifying rectangular and equatorial coordinates of reference stars. Astrometric reduction for all objects in the equatorial coordinate system ( α , δ ) of the Tycho‐2 catalog at the epoch of observation. Photometric reduction of instrumental stellar values m in the system of photoelectric magnitudes B pe (Andruk et al ()).…”

Section: Processing Of Photographic Platesmentioning

confidence: 99%

“…For the construction of characteristic curves for each photographic plates, the B‐magnitudes of stars from a specially created catalog and software (Andruk et al (), Relke et al ()) were used as photometric standard stars. Convergence between the calculated and the photoelectric magnitudes equals σ B = 0. m 16.…”

Section: The Accuracy Of the New Catalogmentioning

confidence: 99%

Catalog of equatorial coordinates and B‐magnitudes of the Kitab's part of the FON project

Yuldoshev¹,

Protsyuk

Relke³

et al. 2019

Astron Nachr

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We present a catalog of stars with equatorial coordinates α and δ and B‐magnitudes of stars for the Kitab's section of the FON project (FON‐Kitab). The photographic plates of the FON project were exposed on the double telescope Double Zeiss Astrograph (DAZ, D/F = 40/300, 69″/mm) at the Kitab observatory of the Republic of Uzbekistan. A total of 1963 plates, with size of 5.5 × 5.5 degrees (30 × 30 cm or 13,000 × 13,000 pixels) were digitized by Epson Expression 10000XL scanner with 1,200 dpi resolution. The reduction of plates was processed in the four astronomical organizations: Ulugh Beg Astronomical Institute (UBAI) of the Uzbek Academy of Sciences; the Mykolaiv Astronomical Observatory of the Ministry of Education and Science of Ukraine; the Walter Hohmann Observatory of Essen, Germany; and the Main Astronomical Observatory of the National Academy of Sciences of Ukraine. The catalogue contains nearly 13.4 million stars and galaxies from 0° to −20° according to declination down to B = 17. m5 in the middle epoch of observation 1985.0. The coordinates of the stars and galaxies were obtained from the Tycho‐2 catalogue, while B‐magnitudes were determined in the system of photoelectric standards. The mean internal errors of the new catalogue for all objects were σαδ = 0. ′′23 and σB = 0. m15 (for the stars in the range of B = 5m − 14m, the errors are σαδ = 0. ′′085 and σB = 0. m054 for the equatorial coordinates and the B‐magnitudes, respectively). The convergence between the calculated and reference positions was σαδ = 0. ′′042. The convergence with the photoelectric B‐magnitudes is σB = 0. m16. External comparison with UCAC‐4 based on 9,892,697 or 73.8% cross‐identified objects yield σαδ = 0. ′′26.

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About Star Photometry on Digitized Astronegatives

Cited by 8 publications

References 14 publications

Exploring nine simultaneously occurring transients on April 12th 1950

Exploring nine simultaneously occurring transients on April 12th 1950

Test of the scanner for expression the astrometric and photometric parameters from the digitized plates

Catalog of equatorial coordinates and B‐magnitudes of the Kitab's part of the FON project

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