Tuesday, January 16, 2007

Getting IRAF the easy way

If you have ever reduced astronomic data, then is almost sure that you know the IRAF package. Despite being old and cumbersome this package is unvaluable for image reduction and analysis in astronomy.

However it's installation is a quite involved ritual, well, not anymore. Realizing that the entry where I discussed a debian package for IRAF was the most visited one, I am posting a much better solution: installation scripts, you can use this scripts for installing IRAF (and related packages like ds9) in ubuntu, and in Scientific Linux (this script should also work in Opensuse and Fedora). Just download them anywere and follow the instructions on screen. This scripts are only small modifications from the original one by amd77. Just make sure you have installed csh (it is in the universe repository in ubuntu and quite probably in the distribution media of Fedora and Opensuse) , you just need to run the comand: bash installiraf_* and enter your password in Ubuntu or the root password in other distro, so here are the scripts (links not working):
After running the script you should run the command mkiraf for creating a login.cl file, I have that file in my home directory but you can put it anywhere, just remember to start iraf (the command is cl) from the same directory.


Since I posted this (quite a long ago) there have been all sort of changes in of libraries/packages included in modern distributions. Since there is no simple way to address this isssue (there are 6 versions of Ubuntu, 6 of Fedora and 5 of opensuse in the past 3 years, and that not counting that both come in 32 and 64 bit versions) I declare the scripts dead.

Nonetheless, an iso image which includes an useful installer is now being offered at: http://www.astro.uson.mx/favilac/downloads/ubuntu-iraf/iso/IRAF_Ubuntu.iso. Just keep in mind that it only works for 32 bit kernels (which are the majority of installed kernels, anyway).

The same autor also offers a (rather outdated) set of rpms at http://www.astro.uson.mx/favilac/downloads/IRAF/ . Find out which one is better suited for your distro and add it to your repos. I have not tried to install from these rpms so I can not comment on them.

For users of 64 bit systems only solution I know is to actually download iraf from iraf.net and proceed to install as detailed in the installation manual.

Wednesday, January 10, 2007

News from the AAS meeting

This week in Seattle,Washington will be held the 209th meeting of the American Astronomical Society. This a very important event and there have been some quite interesting results already anounced.

The findings of the COSMOS team consisting of a weak lensing survey of a 1.6 square degree patch of the sky have gathered a lot of attention. This a rather big portion of the sky (around 9 full moons), this technique measures the distortions (gravitational lenses) produced by the mass between the source objects and the observer, I had already discussed it in relation with the Bullet Cluster. We now have a map of the dark matter in this region of the sky and it shows clearly how the dark matter is getting clumpier by the effect of gravity. I won't go into further details, mostly because many others (Clifford, Phil, Sean, Angela) have already blogged about it.

Another interesting announcement has been the detection of a Triple Quasar using the Keck telescopes and the VLT by a team lead by George Djorgovski. This system known as LBQS 1429-008 was already known to be a doble quasar, but the new deep images show a faint third member. This is interesting mostly because it supports the idea that quasars are more frequent in intereacting enviroments as the gravitational interactions throw large ammounts of material in to the central black holes of this galaxies. You can find more info here.

Stay tuned for more news, this week will surely have more interesting findings!

Watch for comet McNaught, today!

Comet McNaught has brightened this week to the point it is readily observable, even in large cities! If you are living at northern latitutes and have a clear southwestern sky you can try to watch it, it might be a very nice sight. Depending on your latitude you can watch it up to the friday or saturday.

The comet should be very low, close to the horizon, at 15-20 degrees from Venus (depending of your latitude). For more detailed instructions go to SkyTonight.com site, they also have a nice photo gallery.