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Ursa Astronomical Association
Kopernikuksentie 1
00130 Helsinki

Ursa Astronomical Association

Polaris - 9.3.2021 at 21.45 - 9.3.2021 at 22.45 Tampere Observation number 96760

Visibility III / V

Pekka Rautajoki, Tampereen Ursa

The North Star, or Polaris (bongaa 100 object number 45), is a multiple star whose A-component visible to the naked eye shines with the brightness of the 2nd magnitude. The dim 9th magnitude companion Alfa UMi B is still reasonably easy to see with a small telescope - the difference in brightness between A and B is quite dramatic. Since Polaris is only less than one degree from the celestial pole, the rotation of a pair of stars can be followed as a clear indication of the rotation of the Earth (or of course the rotation of the dome of the starry sky!). A right-turned pair of drawings is made every hour; in the telescope image field, the view was a mirror image. When the A component was kept centered in the center of the image field, the B component rotated in the image field at about five o'clock to six o'clock in the direction of the hour. Bongaa 100 North Star ( #45), Double #37) and Earth's Rotation ( #85) #bongaa100

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Additional information
  • Observation target
    • Deep space object
  • Designation
    • Polaris
    • Keskitaso
  • Constellation
    • Ursa Minor
  • Field of view
  • 0.5 degrees
  • Magnification
    • 100
  • Weather
    • -13C, selkeää
  • Darkness
    • Mediocre
  • Seeing
    • Average
  • Stars
    • Multiple star system info

      Moninkertainen tähtijärjestelmä on sellainen, jossa kolme tai useampi tähteä on painovoiman vuoksi sidoksissa toisiinsa. Tähdet kiertävät yhteistä massakeskipistettä. 

      Jos tähtiä, jotka kiertävät toisiaan, on vain kaksi kappaletta, tällaista järjestelmää kutsutaan kaksoistähdeksi. 


Technical information

TeleVue 85 lens telescope, TeleVue Tele Pod alt-az tripod, Nagler 3-6mm eyepiece (@ 6mm, 100x). Photo: Conte white pen, Daler & Rowney black paper)

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