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Workshop on Python and IRAF/PyRAF

Between 12 to 19 of September 2016, we organized the Ondřejov Summer School 2016, which was held at the Stellar Stellar Department of the Astronomical Institute (Czech Academy of Sciences), in Ondřejov. The main aim of the school was to provide students hands-on experience with real observational data, i.e. to understand observations, reduce them, and […]

Issues with IRAF tasks in 64bit machines

I have been working lately with IRAF/daophot with the PyRAF environment in a 32bit machine and everything is smooth except for the fact that it takes many hours to finish the run in each field I examine. As I would like to finish this analysis as soon as possible I opted to use a 64bit […]

Starting IRAF takes too looooong

Does it seams that IRAF is getting too much time to start? And if it starts do you see cannot access host ‘iraf.noao.edu:80’ ? If yes, then if you also try iraf.noao.edu then you will notice that it does take too much time to open (if…it opens!). So, in this case the server is down […]

Ureka – one package to install them all!

Among the simplest installation methods to install IRAF are SciSoft (for RedHat/Fedora based distributions) and Fernando Avila Castro iso files (for Ubuntu/Debian based distributions). However, both require root privileges. What can you do when you do not have these permissions? Ureka [1] comes in rescue! It is easy to install (download and run the installer![2]) […]

Spectrophotometry with IRAF’s sbands

After a long time I finally managed to understand how to use IRAF’s sbands, along with a standard star and a filter. 1. If you want to use a spectrum from the standard star library of IRAF, you have to convert it from a .dat file to an image file .fits – Spectra files located […]

Where are the stsdas/synphot template spectra?

After having looked and searched into the whole IRAF/PyRAF directory to point out the directory that contains the template spectra for the stsdas/synphot package it was just a matter of a quick look at the front page of the package to resolve the issue! As it is said: “Since the data files used by synphot […]

Panic with DAOPHOT’s allstar job

While doing photometry in some rather large images with DAOPHOT, the allstar I experienced a panic from IRAF: PANIC in `/iraf/iraf/noao/bin.linux/x_daophot.e’: Memory has been corrupted By googling the exact error I hit on this post in iraf.net (#136679) where the problem presented was exactly the same. The solution is simple to change the cache parameter […]

About licensing

Stumbled upon the various different licenses I though to write down some conclusions (if I really got into any…). A nice comparison table of free software licenses is given in the Wikipedia where it is easily to see which licenses allow: (i) the link with other licenses and (ii) releasing under different license. So, in […]

IRAF’s error message 502 and pixel value replacement

While running a data reduction of IR observations with IRAF, the ccdproc printed this error: ERROR (502, “floating point invalid operation”) which means that some values of the image used (the flat image in this case) are not suitable for the performing mathematical actions (like division with 0s). Moreover the IR ccds have many bad […]

IRAF’s flatcombine and darkcombine relation with ccdproc

Flatcombine and Darkcombine (based on imcombine both) in IRAF just combine the images given as input to create a master flat / dark image without performing any normalization. This is done when using ccdproc with the parameters flatcor and darkcor set to yes.