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Re: (meteorobs) Re: UT for Geminids?



G'Day All

I agree with Robert re Singapore and similar latitudes, according to my
calculations for Australia, the radiant rises in the east coast of
Australia at between 9.30 pm and 10.30 pm local time (ignoring daylight
saving) depending on latitude (9.30 around Cairns, 10.30 around Melbourne).
This is 10.30 and 11.30 UT respectively, using Roberts' value of 14.00 UT
time on the 14th for the peak, this is midnight local time (or 1 am for the
daylight saving states) on the 14th/15th border. 

So for people in SE asia, New Zealand and Australia, the night of the
14th/15th will host the peak, with the nights of 13/14 and 15/16 bracketing
the peak.

However, in Southern Australia and New Zealand, the radiant doesn't get
above 15 degrees above the horizon until after midnight local time as well,
so viewing will not be ideal. Won't stop me looking though :-)

At 01:04 PM 12/8/99 -0800, Robert Lunsford wrote:
>Nitpick time!
>
>According to my imprecise calculations using Castor as a guide the
>radiant cumulates in Singapore at 0210 local time. OK then, instead of
>moonset to 0300 I'll say moonset to 0400 is the best time to watch from
>Singapore. One point for Lew :)
>
>As for the 12/13 being better lets do a little calculating using 0200
>local time as the center of our watch since this is the time the radiant
>is highest above the horizon. 
>
>The predicted peak has been stated as occurring anywhere from 1000 to
>1800 Universal Time on December 14. Let's use 1400.
>
>1400 UT in Singapore would be 2100 local time also on the evening of the
>14th. At 0200 local time on the morning of the 15th you would only be 5
>hours after the predicted time of maximum.
>
>On the 13/14 at 0200 you would be watching 19 hours before maximum
>activity.
>
>On the 12/13 at 0200 you would be watching 43 hours before maximum
>activity.
>
>I stand corrected! The night of December 14/15 seems to be the best! Is
>my logic faulty? I'm not use to dealing with locations just west of the 
>International Date Line.
>
>From this it would also seem that the night of 15/16 would be good from
>Singapore. As Norman mentioned though, rates do fall off soon after
>maximum activity so I would presume that rates on the 15/16 would be 
>less than those seen on the 13/14 from Singapore.
>
>From the Americas it would seem that Lew's statement would hold true
>with 12/13 being better than 14/15. I plan to be out all 3 nights to see
>exactly what happens!
>
>Thanks for bringing this up Lew! It seems I goofed on both accounts.
>That's what happens when you open your mouth before totally analyzing
>the situation.
>
>Bob Lunsford
>
>
>Lew Gramer wrote:
>> 
>> As usual, Bob Lunsford concisely stated the key point on the Geminids:
>> get out and observe ALL THREE NIGHTS 12-15 Dec, from moonset onward!
>> 
>> One nit to pick (I know you love when I do this, Bob!):
>> 
>> >concerned with which DAY is best to observe. The Geminids will produce
>> >the most activity between moonset and 0300 local time for EVERYBODY
>> >located ANYWHERE! The best night to watch will most likely be December
>> >13/14 followed closely by the 14/15.
>> 
>> For those in certain longitudes and latitudes, it seems - particularly
>> those in the tropics and Southern Hemisphere - 12/13 Dec *MAY* actually
>> be better than 14/15 Dec - especially if Norman's statement about rapid
>> rate fall-offs after the GEM peak is correct. In Singapore for example,
>> the Geminid radiant is only just culminating at 3am local time!
>> 
>> And of course one thing is for sure: if you decide to skip a clear night
>> on 12/13 Dec, you are tempting the Cloud Gods to hand you a disappointment
>> on the later nights 13/14 and 14/15 Dec... Take it from an observer under
>> the Murky Pond of New England weather - don't tempt fate! Get out on any
>> clear night early next week! :)
>> 
>> Clear skies all,
>> Lew
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