9 lines
1.0 KiB
Markdown
9 lines
1.0 KiB
Markdown
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name: Porrima (γ Virginis)
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constellation: Vir
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created_by: 8mag
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created_date: 2022-01-21 17:00:00
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updated_by: skybber
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updated_date: 2022-02-04 20:29:33.840350
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one of the most beautiful double stars in the sky, both yellow-white components have almost the same brightness of 3.5mag and at the same distance of 3" they can be observed with a 6 cm telescope. Their orbital period around their common centre of gravity is 171.85 years. They reached their greatest separation in 1920 - 6.2", so they could be seen in a 5 cm telescope. Meanwhile, their distance from each other is rapidly decreasing. In 1985 the value reached 3.5", in 2000 only 1.8". Therefore, nowadays we need at least 200 mm to distinguish two point stars in good seeing conditions. In 2007 the separation will be even smaller, reaching only 0.3", and therefore we will need a much larger telescope to resolve them. The system is 32 light years away. Five arc degrees to the north lies the brightest quasar - a 13th magnitude, designated 3 C 273, approximately 3 billion light years away. |