(meteorobs) Large fireball frequency calculations - Needs updating
J.L. Brower
jbrower at meteorchaser.net
Fri Oct 31 10:24:05 EDT 2008
Hi Larry,
I asked Joe Chavez about the amplitude data in the .txt output file
after I caught several fireball events.
Chavez and Spaulding informed me for the Sentinel III camera system
you can move the camera during a full moon and record the response as
you suggested. Then do the following:
If the amplitude response of the full moon to be XM, you can calculate
the magnitude of any event of amplitude X with following formula:
Magnitude = -12.7 – 2.5 * log10( X / XM )
This assumes that the magnitude of the full moon is –12.7
I hope this helps.
Jeff
On 30-Oct-08, at 21:23 , stange wrote:
> Interesting graph.
>
> The problem as I see it is in accurately comparing fireball intensity
> (peaks) against fixed references..
>
> Soon as I get done updating my website of old pic's of 2007 & 2008,
> I want
> to (try) calibrating the Python light curve against moon phases.
> Maybe a
> trial moving of the camera enough to cause a trigger and to get a
> brief
> light curve peak, or an off/on cable connector....something along
> those
> lines. It could work with a static picture but I have not checked
> yet, or
> given it any real thought yet as to best way.
>
> Should work if brightness and contrast settings are not changed
> afterward
> which would change the calibration.
>
> YCSentinel
>
> ----- Original Message -----
> From: "Thomas Ashcraft" <ashcraft at heliotown.com>
> To: "Global Meteor Observing Forum" <meteorobs at meteorobs.org>
> Sent: 2008/10/30 20:42
> Subject: (meteorobs) Large fireball frequency calculations - Needs
> updating
>
>
>>
>>
>> For what it's worth :
>>
>> The fireball frequency calculations that are referred at
>> http://www.spaceweather.com/glossary/frequentfireballs.htm?PHPSESSID=27ojbhs2oliu6kadsjaj0gbhd3
>>
>> seem to me to be way underestimated.
>>
>> "According to his calculations, fireballs as bright as Venus appear
>> somewhere on Earth more than 100 times daily. Fireballs as bright
>> as a
>> quarter Moon occur once every ten days, and fireballs as bright as a
>> full Moon once every five months."
>>
>> My own camera system has captured four -13 magnitude events in the
>> past
>> year.
>>
>> So with fresh data from the various all-sky fireball networks maybe
>> these calculations can be updated to give a more accurate picture.
>>
>> Thomas Ashcraft
>> New Mexico
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