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The SOCIETY for POPULAR ASTRONOMY
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Special Electronic News Bulletin 2005 September 9
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GRAZING OCCULTATION OF KAPPA CAPRICORNI
- September 15, 2005
By Jon Harper Occultation Section
During the evening of Thursday 15th September there will be a lunar
occultation of the m(v)4.7 star Kappa Capricorni (ZC 3175). The graze
line crosses the country from SSW to NNE. In this particular occultation,
Kappa Capricorni appears to graze the gibbous waxing moon's north
western (lunar) limb from the following places: The graze line hits
mainland Britain at Port Talbot in South Wales, it then proceeds via
Brecon, Crewe in Cheshire, Ashton-under-Lyne towards Huddersfield
and Leeds in West Yorkshire. From Leeds, the path of the graze
continues north eastwards to Thirsk in North Yorkshire, until it reaches
the North Sea at Saltburn-by-the-Sea.
Observers south and east of this line will see a full occultation of the
star, but those west and north will see only a close conjunction.
Here are the approximate times: (UT)
Port Talbot ----- 20h 10
Brecon ---------- 20h 11
Crewe ----------- 20h 14
Ashton ---------- 20h 15
Huddersfield --- 20h 16
Leeds ------------ 20h 16
Thirsk ------------ 20h 17
Saltburn --------- 20h 18
(Remember to add 1 hour for BST)
If you wish to observe and record this type of occultation event from a
position near to the graze line, the simplest way is to have a tape recorder
and an audible, accurate time signal being played in the background
(e.g. from MSF Rugby) so that it can be recorded on your tape). In a
grazing occultation, the star seems to skim along the limb of the moon
and can undergo a number of short occultations as the star disappears
behind mountain peaks and reappears over lunar valleys. So as this is
likely to happen several times in quick succession, you verbally record
"OUT" and "IN" as the star disappears and reappears.
If an audible time signal is not available, then record the "OUTs" and
"INs", as above --- but at the first "OUT" start a good
sports stopwatch.
When the grazing occultation is completely over, stop the stopwatch
against an accurate radio controlled clock (at,say 20h 30m 00s UT for
this event) and deduct the elapsed time recorded on the stop watch from
the clock time (when you stopped the stopwatch)). You'll then have the
time when the first occultation event took place and from that you can
use your stopwatch again to measure the intervals of your recording
giving you an accurate time for all the graze events.
If you have clear skies on the 15th. and do manage to observe this event,
be it occultation, graze or appulse then do please report your observation
and send it to my e-mail address: jonvran@aol.com
PHILIP'S NEWISH TITLE
NEW EDITION! PHILIP'S GUIDE TO THE NIGHT SKY (48-page paperback,
£4.99, ISBN 0540087017). SIR PATRICK MOORE takes the novice astronomer
on a guided tour of the stars and constellations of the northern
hemisphere. An accessible work, clearly and concisely written.
Bulletin compiled by Clive Down
(c) 2005 the Society for Popular Astronomy
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