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 Post subject: Low-Down Stars
PostPosted: Fri Feb 16, 2018 3:34 pm 
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Joined: Sun May 11, 2008 6:11 pm
Posts: 3303
Location: Portslade, Sussex Lat 50deg 51min Long 0deg 13mins West
Observing Far-Southern Stars. 15th February 2018, 2230-2300.
After returning home from thursday's meeting of the Foredown Tower Astronomers, the sky was very clear and so I ventured out into the back-garden with the Acuter DS65 spotter c/w 25mm eyepiece (giving a magnification of x15) on a light-weight tripod to look at some southern stars. There is a narrow visiblity gap between the corner of my house and the western edge of the row of houses in the south, which allows a limited view much lower down in the south-west, from my garden. With SIRIUS shining brrilliantly. at southern declination of 16.7 degrees (-16.7 degrees), I headed south in the scope to delta Canis Majoris (called WEZEN), a 2nd magnitude star at declination -26.24 degrees. This led me on to epsilon (called ADHARA) at magnitude 1.5. at declination -28.58 degrees. As time passed and by repositioning the tripod, I was able to then locate eta (ALUDRA), a 2nd magnitude star at declination -29.18 degrees which was across to the east. Finally I came across a rather large-size group of a few faint stars, rather in a rectangular layout, even further south. This was labeled Cr 132. at declination -31.10 degrees in Collinder's catalogue of star-clusters and is about 15 degrees lower down than SIRIUS. This starcluster is slightly further south than the star 2 Lupi (Flamsteed star 2, in Lupus), the only Lupine star I have ever seen!). How far you can see south depends on one's latitude. So on the South Coast we do have an advantage. By deducting the observer's latitude from 90 degrees, we can calculate the theoretical visibility limit for such southern stars. regards maf


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 Post subject: Re: Low-Down Stars
PostPosted: Fri Feb 16, 2018 4:24 pm 
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Joined: Thu Jun 02, 2016 11:32 am
Posts: 478
Location: New Farnley, Leeds lat 53.8N long 1.6W
Mike, a really interesting observation. At your latitude, your southern horizon should be about declination -39 degrees looking due south, if I've got my sums right. Of course that is the maximum southerly declination that will culminate on your horizon; it will of course be less than that figure the further round to the west that you are able to observe from your garden. Sorry to be so boring! But if you could pan down just a few more degrees south of Cr 132 (maybe from the hill or the Tower???), you will come to a very, very interesting group of stars in the field of Pi Puppis (at about 36 south). This is the cluster Cr 135. Pi is an orange looking (supergiant) star of mag 2.7. What makes it interesting is the close proximity of three 4th and 5th mag white stars that make for an eye catching tight little group with pi. Recently they were recognised as a real association from the Hipparcos data, with pi being the most evolved of the cluster. I've seen 'em from more southerly climes but it's a different story from here. Probably not possible.
Kind thoughts, Bob


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 Post subject: Re: Low-Down Stars
PostPosted: Sat Feb 17, 2018 7:27 am 
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Joined: Sun May 11, 2008 6:11 pm
Posts: 3303
Location: Portslade, Sussex Lat 50deg 51min Long 0deg 13mins West
Not boring at all, Bob. this good, important skywatching stuff. One of the advantages of viewing from my garden is that it is rather dark, once venturing without, even to Foredown Hill is all those the dammed lights! From Emmaus, where the FTA meet now, SIRIUS was dancing amongst the trees! regards mike


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