[Aavso-photometry] Hot pixels and precision.

[Michael Koppelman]

You should also be able to create a bad pixel mask and them replace 
those pixel values with an average or median of the surrounding pixels. 
This should not be a no-no in photometry, AFAIK. Both IRAF and Mira 
have capabilities for this.

Cheers,
Michael Koppelman
http://www.lolife.com/astronomy/



On Feb 16, 2005, at 4:20 AM, Pedro Pastor wrote:

> I have recently acquired a ST-10 camera and I am in the process to get
> to know how it works.
>
> The first thing I did notice is the great number of hot pixels it
> produces (at least compared with my previous MX916).
>
> I’ve tried to eliminate those hot pixels doing many dark frames and
> combining them via “Median combine” or “Sigma reject”. This produces a
> nice Master dark frame, BUT that’s not enough for suppressing the hot
> pixels from the “Light frames”.
>
> If I would be doing “post card” CCD images I’d take many light frames
> and I’d Sigma combine them for eliminating hot pixels, BUT that’s not
> the case for photometry.
>
> The point is: What would you recommend me to do? (Apart from changing
> the CCD camera ;-). Is there any other ST-10 user out there with 
> similar
> problem?
>
> On the other hand, I keep my MX916. One of the reasons for getting the
> ST-10 was the anti-blooming built-in system in the MX916. I think this
> system was affecting my measures but I still don't know how (the
> anti-blooming is only implemented in one specific direction). Could
> someone tell me how MX series anti-bloomming system affect the 
> precision
> of the ADU measures? Is there any good strategy for compensating (or
> correcting) that effect?
>
>
> Thank you very much in advance.
>
> Pedro
>
>
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