(meteorobs) Re: Perseid Video Results

[Robert Lunsford]

Mikhail and All,

You are correct, but the purpose this system is to capture meteors, not 
faint stars. With the proper lens it may indeed be possible to observe 13th 
magnitude stars. The field of view though would be very small, not very good 
for capturing meteors.

The published LM was obtained using the area estimates provided by the IMO. 
The stars were counted while viewing the video on a large television. In the 
absence of moonlight the number of stars counted in each area usually 
exceeds the magnitude limit of +7.5 on the IMO charts.

The actual visual limiting magnitude taken out in the field during these 
observations varied from +6.21 to +6.28

Clear Skies!

Robert Lunsford




----- Original Message ----- 
From: "Mikhail Maslov" <ast3 at ngs.ru>
To: "Global Meteor Observing Forum" <meteorobs at meteorobs.org>
Sent: Sunday, August 27, 2006 7:29 PM
Subject: Re: (meteorobs) Perseid Video Results


> Hello, Robert and all,
>
> Perhaps I understand something wrong, but when I read on the page you
> linked here that "Light enters through the external Nikon 50mm F1.4 lens, 
> then is
> intensified approximately 100,000 times as is passes through the Abex
> Grade A X1332 Gen II intensifier", I calculated, that vLM should be
> 12.5 mag (Log(2.512)100,000) higher comparing to visual one. But it
> is obviously not so, as you give vLM values of 6.5 - 6.7 mag. Why am I
> not correct?
> And another queation: what was vusial LM during these vidoe
> observations?
>
> Best regards, Mikhail Maslov