[Aavso-photometry] Short-Exposure Photometry

[Radu Corlan]

On Tue, 13 Jul 2004, Michael Koppelman wrote:

> Thanks to everyone would replied. Yes, it must be scintillation. That 
> sucks because I can't go longer or I'll saturate. I guess I can work in 
> B and see how that works out.

I use the following formula for estimating scintillation (by Dravins i 
think):

scint = (0.09 * A ^ 1.75) / (D ^ 0.66 * sqrt(2 * t))

Where A is the airmass, D is the aperture in cm, t is the integartion time 
in seconds. This formula excludes a correction for altitude (which only 
becomes significant above 1000-2000m or so). Scintillation also depends on 
local conditions, of course - a factor of 0.5..3.0 could apply. But it;s 
never an order of magnitude better (or worse).

Radu

> 
> Thanks!
> Michael
> 
> On Jul 13, 2004, at 10:03 AM, <Arto.Oksanen at tietoenator.com> wrote:
> 
> > Been there and seen the same. It is scintillation or twinking of the 
> > star by atmospheric turbulence. The shorter the exposure the more the 
> > star brighness seem to vary.
> 
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Radu Corlan       Snail Mail: Bucuresti sect. 1, 
rcorlan at pcnet.ro  str. Argentina nr. 28, Romania

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