Archive for January, 2011

Reverse axis in matplotlib’s plot

Posted January 28, 2011 By grigoris

Ok, maybe this post is not that important but it is one of the things that, although they seem so simple, you struggle to find the answer. After having downloaded matplotlib (a powerful library for 2D plots) my first plot through python was a success. But since I was plotting magnitudes I wanted the axis to be reversed. So, it took almost half a day to find out how :


where “plt” is “matplotlib.pyplot”.

Thanks to JK-2’s answer !!

Book – Skinakas Observatory: A view at the Universe

Posted January 27, 2011 By grigoris

A great new book is available for the Crete Univesrity Press, Skinakas Observatory: A view at the Universe (language: Greek).

It is a photo tour around the Universe through magnificent images obtained from the 1.3m telescope of Skinakas Observatory.

Contents: Introduction / Skinakas Observatory: a short historical review / Skinakas: a great astronomical location / Coloured astronomical images / Solar system / Stars / Emission and reflection nebulae – dark nebulae / Planetary nebulae / Supernovae remnants / Open clusters / Globular clusters / Galaxies

A video made for the Astrophysics group of Crete, presenting the activities of the group (in Greek language only).

AAO’s Configure – fiber arrangement for AAOmega

Posted January 21, 2011 By grigoris

AAOmega is one of the instruments of Anglo-Australian Observatory. It is a multi-purpose, bench mounted, fibre fed, double-beam spectrograph with two main observing modes: i. Multiple-object spectroscopy using the existing 2dF top, ii. Integral field spectroscopy at Cassegrain focus.

In order to use the multiple-object mode you need to know which fiber goes where. Configure is the program that solves for the best arrangement of the fibers (it is also used for 2df, FLAMES and 6df setups). Download the latest version (currently 7.9) from the configure ftp site.

Installing Configure is simple, since you just place the files in a desired directory and run the program! You can make of course all kinds of links and aliases.

But in order for Configure to run properly you need the latest files about the configuration and the status of fibers and system, updated each day with previous’ night configuration.

So, just go to the ftp site where the latest config files are stored and download these files (for AAOmega use):

tdFconstants400.sds <fibers’ configuration
tdFdistortion0.sds  <distortion map for plate 0
tdFdistortion1.sds  <distortion map for plate 1
tdFlinear0.sds  <linear astrometric coefficients for plate 0
tdFlinear1.sds <linear astrometric coefficients for plate 1

After downloading the files you just place them in the same directory and you are finished!

The AAOmega spectrograph of Anglo-Australian Observatory uses the 2dfdr v4 data redution package (version 4 removes most dependencies on STARLINK packages, earlier version will need also the STARLINK to be installed, so it is not recommended).

After downloading the necessary file (ftp and get 2dfdr-linux_x86_RH_5_3-4.0.tgz) you just need to set an environment variable and run the setup script (see also the CookBook):

setenv DRCONTROL_DIR /home/pathtoprogram/2dfdr-linux_x86_RH_5_3
source $DRCONTROL_DIR/2dfdr_setup

[or else edit the ~/.tcshrc file with the above commands in order to have available the program each time you invoke the shell].

So, to start the processing you just have to get to your working directory where there is a set of observations with a particular field plate and type

drcontrol aaomega.idx &

which selects defaults for AAOmega (for more options see CookBook and the v4’s page).

Some times (if not all the times) an extra library is needed: libg2c0, a library needed for GNU Fortran 77 applications linked against the shared library.

In the case of the 32bit machine you just find the the appropriate package containing the library and install it (through any covenient terminal or graphical way).

In the case of 64bit machine the same library has to be downloaded and used, as 2dfdr is a 32bit program. Download the i386 package but this time extract (NOT install) the files (details on extraction from .deb or .rpg files here). Copy (or move) the extracted files to /usr/lib32 directory and you are done! Installing a 64bit version of the library will not solve the problem.

Happy data processing !