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Re: (meteorobs) Re: (LINMI) Leonids from Hawaii - So Disgusting

I feel the rate prediction was way off. I initially thought the time prediction was a bit off too, but have now reconsidered. Looking at my minute-by-minute data, it appears I saw a "peak" of 4 LEO in 3 minutes centered at 10:59UT. Very poor rate for a LM of 5.3 and radiant elevation about 9 deg., but relative to the rest of the minutes and accounting for radiant elevation, this seems the highest rate period I saw. So, its quite a bit later than what others reported (10:45-10:55UT). 

But, if this stream turns out to be very narrow one, as the data of a sharp peak seems to imply, there could be an explanation for the different peak times. Since the earth moves through space at about 1100miles/minute, it seems plausible that observers to the east would intersect this stream a few minutes earlier. For example the center of the continental US is about 4000 miles east of Hawaii, so it would intersect the stream about 4 minutes earlier. This would account for the mainland observers seeing it around 10:55UT and I saw it around 10:59UT.

In fact, I suppose all the predictions were made using geocentric, so a detailed calculation of the peak times based on specific geographic locations would likely explain the time differences everyone saw.

Still no idea why my rates were so poor. I observed under about the best sky possible. Only my radiant elevation was low, less than 10deg around the peak. It would mean I see about 30% of the rates compared to west coast observers, but I saw much less than that. It wasn't my vision problem, because I saw 24 sporadics in 2.5hours. Apparently, the Leonids stream was just not as dense at that moment when Hawaii hit it..

Mike Linnolt


--- J A <meteorobs@hotmail.com> wrote:
> >>But it soon became clear, as the radiant rose
> higher, that the 10UT "peak" 
> >>just wasn't anywhere near what was predicted.
> 
> 
> Mike,
> 
> I'm sorry that you didnt see any sig activity from
> your great locale..  Are 
> you saying the TIME prediction was way off or the
> RATE predciction were off? 
>   or both?  Seeing 50 between 1015-1030UT under full
> moon was very exciting 
> indeed, tho the average magnitude (which I haven't
> calc'd yet, was around 3. 
>   When I typed in my counts in the Leonid Quick
> Report.. when done, it 
> calc'd MY ZHR at a ~700-800.
> That is certainly sig different that the ZHRs of
> 1000s that I saw predicted.
> 
> How much does the near Full Moon play? and what
> would have been, say, my 
> ZHR, had it ben a moonless night? Do the models,
> Fischer, Jenniskens, etc 
> take into account moonlight?  anyone?
> 
> Just some questions I'm thinking about reading your
> posts ;-)
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