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How many degrees above the horizon is Centaurus when seen from the West Midlands?


Matt1979
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I am pretty sure that I saw a few stars in Centaurus at around 11.00-11.45 on 4th May. I had a fairly clear view to the southern horizon from my local hill (the southern horizon from my garden is limited due to the hill) and I saw two fairly bright stars with my 60x spotting scope around two and a half inches above the horizon below and to the left of Spica. I don't know how to measure degrees so would anyone be able help me on this, please?

I have had a good look on Redshift 7 although the horizons aren't always accurate (mountains, city etc.). I used a completely flat horizon although this wasn't 100% accurate as there is still some high ground in the distance from where I observed, although the stars I saw were very low.

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The northern limit of Centaurus is at -30 Degrees. The 2nd magnitude star Menkent is at -36 deg. and most likely to be the one seen. Thus from Birmingham at +52.4 deg. it will only get 1.5 deg above the horizon. There are a few 4th -5th mag stars a few degrees above that but they would need perfect skies to the horizon to be seen with optical aid. At 4 degrees above the horizon the atmospheric extinction is 2 magnitudes. Menkent , at 1.5 deg. will appear as approx mag 4.7.

Nigel

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Subtract your latitude from 90 and this gives you the greatest southern declination you can get (excluding atmospheric refraction). Subtract the declination of the object from this result (assuming it is S decl), and that will give you it's culmination altitude when due south.

HTH

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If you consider that each constellation has got its territory in the sky, together forming a jigsaw, you can see a small fraction of its most northern edge. However no stars brighter than 4.3ish can be seen in practice. The real test is to spot magnitude 2 Menkent (Theta) that in theory you may see. I don't know anyone that spotted it.

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The northern limit of Centaurus is at -30 Degrees. The 2nd magnitude star Menkent is at -36 deg. and most likely to be the one seen. Thus from Birmingham at +52.4 deg. it will only get 1.5 deg above the horizon. There are a few 4th -5th mag stars a few degrees above that but they would need perfect skies to the horizon to be seen with optical aid. At 4 degrees above the horizon the atmospheric extinction is 2 magnitudes. Menkent , at 1.5 deg. will appear as approx mag 4.7.

Nigel

Thanks for letting me know. I haven't been able to look again due to bad weather. I think I probably did see Menkent, as the star did seem a bit loo low to be in Hydra, and Redshift 7 doesn't show any fairly bright stars in the lower part of Hydra - the star I saw was fairly bright given the atmospheric extinction and light pollution.

I have yet to see Lupus, which could be a problem as the part of the constellation visible appears close to the Birmingham skyline from my location. Birmingham is around 12 miles away and you can imagine how light polluted the sky looks.

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