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Dear all,<br>
<br>
at first sight the setting described by Ewout looks quite ok.<br>
The advantage of full dynamic range (saturation at 65000) is
significant, while the increase in read noise is only marginal when
compared to the few dozen poisson noise on a 300 sec dark sky. <br>
<br>
regards<br>
Edwin<br>
<br>
On 29-4-2011 3:11, helmich wrote:
<blockquote cite="mid:011503d9fc4e9a292f20600b21781ed2@astro.rug.nl"
type="cite">
<p>Hi everyone,</p>
<p>Part of this mail is covered in previous mails. The first day
we have spent mostly on gain, readnoise, quickcheck etc. meant
to determine the best FIERA/preamp settings. I think we have not
reached an optimal solution. Input from Groningen is
appreciated: Olaf & co from ESO are very eager to get this
out of the way, and for us it is best as well if we can settle
on final settings now. With the FIERA filtering changed and the
preamp increased as well, we get saturation at ~65000 ADU. Gain
is relatively high ~2.5e/ADU. Readnoise in ADU is ~2.0 ADU, but
in e is high ~5.0 e- (sometimes higher, and therefore slightly
outside specificiations).</p>
<p>If we cannot accept this, then changes of hardware components
are necessary. Obviously, if we can be satisfied with the
current setup this is convenient.</p>
<p>Yesterday was spent with us doing readnoise, quickcheck, bias,
in the morning while afterwards Olaf worked on the instrument.
In the afternoon Bernard & co arrived and they've been
working on shimming. This will continue today and Bernard
estimates is finished this evening at the earliest. </p>
<p>Regards, </p>
<p>Ewout </p>
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