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Ursa Astronomical Association
Kopernikuksentie 1
00130 Helsinki

Ursa Astronomical Association

1477 Bonsdorffia - 3.9.2021 at 21.38 - 3.9.2021 at 21.59 Orimattila, Artjärvi, Tähtikallio Observation number 101028

Visibility III / V

1477 Bonsdorff (1938 CC, 1959 WD) The asteroid on the outer edge of the main zone was photographed on the first night of the September 2021 work. Finland 100 is the target of our project 200. The asteroid was discovered by Yrjö Väisälä on February 6, 1938 in Iso-Heikkilä, Turku. The asteroid is named after the Finnish astronomer Ilmari Bonsdorff (1879-1950). From 1908 he worked as a permanent astronomer at the Pulkova Observatory and as the first director of the Helsinki Geodetic Institute from 1918-1949. Source Wikipedia . Professor Ilmari Bonsdorff was invited to become an honorary member of URSA in 1934. The size of the asteroid is 25.85km and the rotation speed is 7.8h / r. Spectrum class spec_T => XU. When photographed, the asteroid was 1,770au at a distance and closest on October 3, 2021 to 1,666au. The filming already took place in part during Nauttinen twilight.
1Picture. first image in the series1 L60s measured, 2021-09-03UT 18: 38: 24UT 2459461.27666JDUT 23h58m53.29s + 16d09'02.2 "15.509mag Std Dev 432.783 SNR21.635 FWHM3.873", JPL Horizon 18: 38: 24UT 23h58m53.30s + 16d09'01.0 "15.681 mag.
2Picture. last image in the series11 L60s measured, 2021-09-03UT 18: 59: 08UT 2459461.29106JDUT 23h58m52.60s + 16d09'05.2 "15.645mag Std Dev 322.503 SNR46.235 FWHM4.924", JPL Horizon 18: 59: 08UT 23h58m52.63s + 16d09'04.0 "15.681 mag.
3Picture summary image of a stack of L60s 1-20 images, motion is displayed. Asteroid (160678) 2000 CZ140 18,816mag, opaque motion visible. No other asteroids below 20.0 mag are shown. TYC 1722-464-1 v.12.01mag stars used to calibrate the brightness measurement.

Additional information
  • Observation target
    • Asteroid
  • Seeing
    • Average
  • Name of the observation target
    • 1477 Bonsdorffia
Technical information

Alluna RC16, C415 / 3320, Moravian G4-16000EC MkII, filter L, bin3 20 x 60s

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