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Ursa Astronomical Association
Kopernikuksentie 1
00130 Helsinki

Ursa Astronomical Association

Algieba (Gamma Leonis) - 9.5.2022 at 23.40 Vantaa, Pähkinärinne Observation number 106707

Visibility Unclassified

Paula Wirtanen, Ursa (Helsinki)

Two stars are very rarely observed here in the Sky Watch, even though they look pretty nice. The moon was nicely close to Regulus and Algieba yesterday, so at the end of a great lunar observation, I still wanted to explore the often-forgotten great double star, Gamma Leon aka Algieba, the lion's neck star (Algieba means lion's crest).

With a 10x eyepiece at 150x magnification, the star was already clearly visible in two, quite close pairs. At 250x magnification, it already clearly distinguished the difference in the size of the stars. In the most handsome double stars, like Albireo, the colors also stand out perfectly, this pair looked the same color, or more or less white in the telescope.

While in the south, this pair of stars appear on top of each other, now the Lion was already in the southwestern sky in the descending direction.

In the drawing (Figure 1), the binary star as it appeared in my telescope in this direction with an angular prism. Figure 2 map image of the time of the Stellarium.

More similar observations
Additional information
  • Observation target
    • Deep space object
  • Designation
    • Algieba (Gamma Leonis)
  • Constellation
    • Leo
  • Magnification
    • 250
  • Weather
    • +5, ohutta yläpilveä, toukokuinen taivas.

  • Seeing
    • Average
  • Limiting magnitude
    • 3
  • Stars
    • Binary star info

      Binary stars are star systems, where there are two stars close each other. Binary stars are classified to optical or physical binaries.

      In optical binary star systems two stars are apparently close each other, but in reality they are located far each other in different distacies.

      In physical binary systems the stars are bound up with gravity and they are orbiting each other. Stellar systems with more than two stars are called multiple star systems.

      Binary star Albireo in Cygnus in composed of blue and yellow star. It is unknown if this of a physical binary. Image Mauri Korpi.


      M40 eli Winnecke 4 on Messierin luetteloon virheellisesti päätynyt tähtipari. Kyseessä on optinen kaksoistähti. Tähdet eivät siis ole fyysisesti lähekkäin. Kuva Tero Hiekkalinna.

      M40 aka Winnecke 4 is stellar pair incorrectly taken into The Messier catalog. It is an optical binary. Image Tero Hiekkalinna.

Technical information

Sky-Watcher Skymax-127 (M127 / 1500), SP 6 mm, angle prism.

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