[AstroPy] Image combination with sigma clipping
Lisa Alborghetti
lisi.alborghetti at gmail.com
Wed Feb 7 01:33:42 EST 2024
Yes, I think it works now!
Thank you very much.
Lisa
> On 6 Feb 2024, at 17:00, Slavin, Jonathan via AstroPy <astropy at python.org> wrote:
>
> Hi Lisa,
>
> Looks to me like the method sigma_clipping of the Combiner object acts on the data in place and has no return statement (and so returns None).
> If that's true then you want something like:
>
> combiner.sigma_clipping(low_thresh=2, high_thresh=5, func='median', dev_func='mad_std')
>
> combined_average = combiner.average_combine()
>
> Regards,
> Jon
>
>
>> Date: Tue, 6 Feb 2024 16:06:40 +0100
>> From: Lisa Alborghetti <lisi.alborghetti at gmail.com <mailto:lisi.alborghetti at gmail.com>>
>> To: astropy at python.org <mailto:astropy at python.org>
>> Subject: [AstroPy] Image combination with sigma clipping
>> Message-ID: <DB96B4E2-270E-4982-9414-EEAF0B56DC05 at gmail.com <mailto:DB96B4E2-270E-4982-9414-EEAF0B56DC05 at gmail.com>>
>> Content-Type: text/plain; charset="utf-8"
>>
>> Hi everybody,
>> I?m new to AstroPy, and I have what I believe to be a very simple question: I have a .fits file, containing a series of 50 images that I want to combine to create a dark image of my CCD. Before averaging, I would like to perform a sigma_clipping using mad_std.
>> I was trying with something like this:
>>
>> from astropy import units as u
>> from astropy.nddata import CCDData
>> from ccdproc import Combiner
>> import numpy as np
>>
>> ccd = CCDData.read('Dark Current/minus_10/5_sec/Background_fits.fits', unit="adu")
>>
>> combiner = Combiner(ccd)
>>
>> combiner_clipped = combiner.sigma_clipping(low_thresh=2, high_thresh=5, func='median', dev_func='mad_std')
>>
>> combined_average = combiner_clipped.average_combine()
>>
>>
>> But it doesn?t seem to be the right way to do it. In fact, I get:
>>
>>
>> ---> 12 combined_average = combiner_clipped.average_combine()
>>
>> AttributeError: 'NoneType' object has no attribute ?average_combine?
>>
>> Can someone help me with this, please?
>> Thank you!
>>
>> Lisa
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