[vsnet-chat 2093] Re: Plotting light curves

[Gianluca Masi <gianmasi@fr.flashnet.it>]

Arne Henden wrote:
> 
> Gianluca wrote:
> >My CCD spends about 30 secs to download and save an image in full
> >resolution (765*510 pixels) and about 7 secs to do the same in mid res
> >(2*2 binning). On V603 Aql I was working in 2*2 binning, acquiring a new
> >frame every 15 seconds. The software automatically saves the pictures
> >and I can leave the instrument unattended. Unfortunately, to do so I
> >have to limit the integration time to max 10 secs...
>
>   Note that, for your case, you integrate for 10 seconds and then have
> 15 seconds of dead time.  That means you are collecting photons for only
> 40 percent of the time.  

The indicated 15 seconds was a total time, including 7 seconds of
integration and other 8 seconds for downloading, saving and restart a
new frame. A new image was started after saving the previous one. This
for the presented light curve of V603 Aql. The reported 10 seconds where
a guess of my max integration time in 2x2 binning before evident
tracking problems. The dead time, when working in 2x2 binning mode, is
about 7, 8 seconds. My note was not clear on this point.

Very interesting what you say about improving efficiency. Unfortunately,
a mount is sometimes difficult to improve, especially for amateurs. I
was thinking to move to a CCD sensor with higher QE.

In order to optimize to S/N ratio and time resolution, how can one
determine the right integration time for her/his target (not too short,
not too long)? How the background brightness influences this (light
pollution, bright moon...)?

Regards,
Gianluca


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* Gianluca Masi                           "Two things fill the soul   *
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