(meteorobs) [Meteorobs] ZHR Table

[Rainer Arlt]

> HR = observed hourly rate; r = population index; LM = your average limiting 
> magnitude; and A = altitude of the shower's radiant above the horizon in 
> degrees
> 
> a) Formula with an LM above 6.5
> 
>        (HR) (r)^1-(LM - 6.5)
> ZHR = ----------------------
>               Sine A
> 
> b) Formula with an LM below 6.5
> 
>         (HR) (r)^6.5-LM
> ZHR = -------------------
>              Sine A

The "above 6.5" formula looks suspicious to me.
Does it actually mean, if LM=7.0, that the
correction is r^(1-0.5) = r^0.5 ? If I am not mis-
interpreting the symbols, it is wrong.

The one and only formula is the second one
>         (HR) (r)^(6.5-LM)
> ZHR = -------------------
>              Sine A

where I have put brackets to make clear the the difference
is taken before the power. At an LM of 7.0, we get
r^(-0.5) which is a number smaller than one. This is
what we want, since an observer with 7.0 sees more meteors
than the "standard" observer at 6.5. Hence the observed
number of meteors is corrected downwards.

Best regards,
Rainer