(meteorobs) Origin of ZHR?

[Julian Parks]

If you have something constructive to add then do so, instead of "And thus 
began an endless source of misunderstanding...."

Perhaps you can enlighten us.  Who is Belatrix?

Julian Parks
Rego Park, NY

----- Original Message ----- 
From: "belatrix" <belatrix at ozemail.com.au>
To: "Global Meteor Observing Forum" <meteorobs at meteorobs.org>
Sent: Sunday, May 13, 2007 12:42 AM
Subject: Re: (meteorobs) Origin of ZHR?


And thus began an endless source of misunderstanding to complete
newcomers to meteor/sky watching LOL

On 13/05/2007, at 1:27 AM, Julian Parks wrote:

> Under Section 15.6, Zenithal Hourly Rate, and Zenithal Magnitude,
> p.202, the 1955/1957 ed. of Sedgwick's, " Observational Astronomy for
> Amateurs," and I quote,  "The ZHR is derived from the observational
> data by applying corrections for the altitude of the radiant and for
> moonlight, if any; generally, however, observations for statistical
> purposes are not made when there is strong moonlight."
>
> "If R is the observed hourly rate, then Rc (the HR corrected for
> radiant altitude a) is given by
>
>                         Rc = R cosec (a+6º)
>
> The correction for moonlight depends upon the lunar phase and the
> incidence of diffusing matter in the atmosphere, and must be
> determined empirically by comparing the numbers per magnitude with
> similar figures relating to a previous, moonless, return of the
> swarm."  End quote.
>
> Julian Parks
> Rego Park, NY
>
>
>
>
> --- In meteorobs at yahoogroups.com, meteors at ... wrote:
>>
>> Julian,
>>
>>> From what I've been able to determine, Opik, Porter, and Oliver all
>> addressed parts of the issue, so maybe Sedgwick is the one who put
> it all
>> together. I'll check my County Libtary for the bood.
>>
>> Is there a copy of the formula?
>>
>> Wayne
>>
>>
>>> Rich,
>>>
>>> If you have a copy of Sedgwick's, "Observational Astronomy for
> Amateurs,"
>>> either the 1955/1957 edition or the fourth edition there is a
> reference to
>>> Meteor Counts and Hourly Rates in Section 15.5 and to Zenithal
> Hourly
>>> Rate, and Zenithal Magnitude in Section 15.6 and a Bibliography
> for E.
>>> Opik, J.G. Porter, C.P. Oliver, et. al. who researched this
> area.  From
>>> the Bibliography the dates I see referred to are 1920, 1921,
> 1923, 1930,
>>> 1931.  These cites are from the Harvard Circ. and ``Journal of
> the British
>>> Astronomical Association among others.  There is also mentioned
> in Section
>>> 15.5 statistical work in the mid-nineteenth century by a Gravier
> and
>>> Schmidt.  Whatever that statistical work is I do not know.
> Sounds like a
>>> trip to the library.
>>>
>>> Hope this helps.
>>>
>>> Julian Parks
>>> Rego Park, NY
>>>
>>> ----- Original Message -----
>>> From: "Richard Taibi" <rjtaibi at ...>
>>> To: <meteorobs at ...>
>>> Sent: Friday, May 11, 2007 9:02 PM
>>> Subject: (meteorobs) Origin of ZHR?
>>>
>>>
>>>> Does anyone know who developed the concept of the Zenithal
> Hourly Rate,
>>>> and
>>>> when it was proposed?
>>>>
>>>> Thanks!
>>>>
>>>> Rich
>>>>
>>>>
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>>
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>
>
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