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Automated image calibration

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dokeeffe
Affiliation
American Association of Variable Star Observers (AAVSO)
Mon, 01/04/2016 - 20:10

Hello all,

I'm starting out in photometry and I've been looking for some software to automate the calibration of images. So far I cant seem to find anything but maybe I'm looking in the wrong places....

I'm mainly interested in Dark subtraction and flat field processing. I was hoping that something like astropy could be used to do the math on the fits image data but I'm not sure. Does anyone have any pointers? I'm looking for something that I would just point to a colleciton of raw image data, appropriate flats and appropriate darks. 

Thanks,

Derek

hambsch
Affiliation
Vereniging Voor Sterrenkunde, Werkgroep Veranderlijke Sterren (Belgium) (VVS)
Tue, 01/05/2016 - 18:01
MUNIWIN

Hi

I would recommend MUNIWIN wich can do what you want to do and is free of charge. It also measures all stars in the field of view as a bonus so new variables can be discovered this way.

http://c-munipack.sourceforge.net/

Josch

TRE
Affiliation
American Association of Variable Star Observers (AAVSO)
Wed, 01/06/2016 - 03:48
linux or WIN

Hi Josch

It does it to come with a windows executable download as the name suggests. No need for a compiler?

The Linux version is fine, but it looks to need compiling. Does it come with a GUI or just command line? Have you used it with Ubuntu?

Are you using linux for both data taking/ telescope pointing and data reduction?

Collin

Would you share your code eventually? I have done some laser profiller image math but it was slow for a single image.

I run Anaconda on the MacBook Air. Have not called astropy yet, I may wait till I get the new Mac because the old one is getting full.

Ray TRE

hambsch
Affiliation
Vereniging Voor Sterrenkunde, Werkgroep Veranderlijke Sterren (Belgium) (VVS)
Wed, 01/06/2016 - 17:18
Windows only

Hi Tre,

 

I am only using windows in V 10 now. MUNIWIN has a GUI and probably the exe is fine to install for Windows, no need for a compiler.

It works perfectly and rather fast on a modern PC (does not take hours even if you have 100dreds of FITS images.

I do not use LINUX in whatever flavor.

Josch

clittlefield
Affiliation
American Association of Variable Star Observers (AAVSO)
Tue, 01/05/2016 - 21:21
Image calibration is straightforward in Python

Hi Derek,

It's relatively straightforward to write a Python script which will open each .fits image in a folder, apply darks and flats, and save the calibrated image. If you're interested, I could help you get started and share some code with you. If you'd prefer to use a GUI, MUNIWIN might be a better bet. Although I haven't used it, I would trust Josch's recommendation.

Josch: Do you know how long it takes MUNIWIN to search an entire time series for new variable stars? I have written some Python code which does this, but it takes around 20 minutes to perform aperture photometry on 800 stars in a time series of 400 images (765 px x 510 px). I'm curious to know if MUNIWIN is faster.

Best Regards,

Colin

 

 

dokeeffe
Affiliation
American Association of Variable Star Observers (AAVSO)
Tue, 01/05/2016 - 22:45
Josh / Colin,
Thanks for the

Josh / Colin,

Thanks for the information! MUNIWIN looks interesting so I'll check that.

Colin I would prefer a script than a GUI so I would be really interested in how you calibrate your images with python. I'm fairly comfortable with python (10+yrs experience with Java). Even if you just pointed me in the general direction. Are you using astropy to do the work on the image data? If you could share some code that would be fantastic :-)

Have you looked at Lemon? https://github.com/vterron/lemon Its supposed to be able to analyse thousands of fits files in 'hours' and do differential photometry. I've installed it but dont have much of my own data yet to try it out for real.

Derek

 

hambsch
Affiliation
Vereniging Voor Sterrenkunde, Werkgroep Veranderlijke Sterren (Belgium) (VVS)
Wed, 01/06/2016 - 17:36
Speed of MUNIWIN

Hi Collin,

I would need to check it out. Of course it depends on your image size. Mine are 4kx4k pixels in 3x3 binning mode. WHen MUNIWIn has done the analysis of all stars and images to switch from one star to the other to check for a periodicity is instantaneous. To process the images is time consuming.

I just tried with 258 V filtered files. It took less than 30 sec to convert them into MUNIWIN format. Running photometry with standard parametrs on the files giving about 750 to 900 stars in the field took about 5 min (a bit more than 1sec per image).

Matching of all imaged to a reference image you have to choose took about 10 sec

To get a light curve took another 5 sec. Changing the aperture is instant as well as selecting variable and comp stars.

I hope this helped.

Josch

 

 

WGR
Affiliation
American Association of Variable Star Observers (AAVSO)
Thu, 01/07/2016 - 01:23
Automated calibration

Hello Derek

Maxim 6 does this auto calibrate nicely.  I have used it for about a year.  Before that, Maxim 5, and it was a bit combursome by comparison. 

Gary

spp
Affiliation
American Association of Variable Star Observers (AAVSO)
Thu, 01/07/2016 - 01:53
AIP

I use AIP (Windows) to do this.  AIP will also stack images at the same time if you like.

Phil