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Ursa Astronomical Association
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00130 Helsinki

Ursa Astronomical Association

(20971) 1981 DR1 - 2.9.2022 at 22.23 - 2.9.2022 at 23.17 Orimattila, Artjärvi, Tähtikallio Observation number 110876

Visibility I / V

Kari Laihia, Toni Veikkolainen, Porin Karhunvartijat

(20971) 1981 DR1 (1981 DR1) A central main belt asteroid imaged on the first evening of 2022 DS days. When photographing Aquarius NGC 6772 bipolar planetary 12mag nebula, this object came into the picture. The Eunomia family asteroid was discovered by the American astronomer Schelte John "Bobby" Bus (b.1956) at the Australian Siding Spring Observatory on February 28, 1981. Bobby Bus has discovered a total of 1683 asteroids and comet 87P/Bus. Source Wikipedia . The size of the small asteroid is 3.73 km. Spectral class S according to the family. When photographing, the asteroid was at a distance of 1.492au and at its closest on July 14, 2022 at 1.229au. Toni photographed the color series and Kari measured L from the images as an asteroid sensor. The Milky Way posed challenges for measurement!

1Fig. first image of the series L120s measured, 2022-09-02T 19:22:49UT 2459825.30751JDUT 19h15m12.41s -02d59'52.1" 19.092mag Std Dev 94.146 SNR2.072 FWHM1.891" ,JPL Horizon 19:22:39m12.41s -02d59'52.1" 02d59'52.5" 18.009mag .

2Fig. last image of the series L120s measured, 2022-09-02T 20:16:09UT 2459825.34454JDUT 19h15m12.70s -03d00'07.0" 18.960mag Std Dev 57.807 SNR2.915 FWHM1.957" , JPL Horizon 20:16h15m12.70s -03d00'07.0" 1 03d00'07.1" 18.009mag .

3 Picture sum picture L120s 1-11 from a stack of pictures, movement is visible. Bipolar NGC 6772 planetary nebula v. 12.1mag. (50734) 2000 EP153 18.44mag , the movement is weakly visible. There are no other asteroids under 20.6 mag in the picture.

TYC 5133-885-1 v.12.06mag star used for brightness measurement calibration.

Additional information
  • Observation target
    • Asteroid
  • Name of the observation target
    • (20971) 1981 DR1
  • Seeing
    • Good
Technical information

Alluna RC16, C415/3320, Moravian G4-16000EC MkII, filter L, bin3 11 x 120s

Comments: 2 pcs
Toni Veikkolainen - 26.11.2022 at 12.00 Report this

Kuvan planetaarinen sumu on Kotkan tähdistössä ja taustatähtien määrä kentässä tosiaankin melkoinen.

Kari Laihia - 27.11.2022 at 08.50 Report this

Tais kirjoittajalta mennä Aqua ja Aqui lyhytmuistissa sekaisin. Kiitos korjauksesta. Olihan tähtien määrä jonkinmoinen haaste n.10000 tunnistettua tähteä ja joukossa 2 himmeätä kohdetta.

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