Archive for 2012

Updating Scisoft in Fedora is rather easy (see the installation details). First if we have already a previous installation we can easily remove it by running (as root): yum remove scisoft-\* and check that the directory /scisoft has been totally removed (if something extra has been added the we should still see the scisoft directory […]

A quick note on how to backup and restore (if necessary) the filesystem. We go to the root directory (/) and as root we run: tar cvpzf backup.tgz –exclude=/lost+found –exclude=/backup.tgz / c: create new archive v: verbose p: preserve permissions z: gzip f: use file (name of file=backup.tgz) We exclude all the directories that we […]

While manipulating some data I came across to, what looked, a strange behavior with the errorbar of matplotlib, when plotting the results from linear to logarithmic scale. Suppose these data: import matplotlib.pyplot as plt import numpy as np s=[19.0, 20.0, 21.0, 22.0, 24.0] v=[36.5, 66.814250000000001, 130.17750000000001, 498.57466666666664, 19.41] verr=[0.28999999999999998, 80.075044597909169, 71.322124839818571, 650.11015891565125, 0.02] plt.errorbar(s,v,yerr=verr) plt.show() […]

Neptune and Triton from Skinakas

By grigoris | Filed in Astronomy

In order to install THELI (GUI version) there is a series of libs and compilers to have already installed prior to THELI (like the fast-fourier transform (fftw), TIFF libraries (libtiff), C and C++ compilers (gcc, g++), Qt3, see the list at the site). Although everything was installed there was still an error in the installation […]

Pluto from Skinakas

By grigoris | Filed in Astronomy

In late August 2012 we (me and Manos Kardasis) tested the video capture method for planetary imaging using the 1.29m Skinakas‘ telescope. Although not aware of what problems to expect we finally didn’t encounter any (as Manos had been really working on this with great care and caution) but for the weather and seeing. So, […]

Blank Fields

By grigoris | Filed in Astronomy

Stumbled upon a very interesting page by Santos Pedraz Marcos with a collection of standard stars, I found this table of blank fields:   Name RA1950 DE1950 Reference Roeser1 00 16 25.0 +16 09 00 CL 0016+16 Cadis1H 01 45 01.3 +02 05 07 Cadis Blank1 04 25 46.0 +54 09 03 PASP 97,363 Cadis9H […]

In the following tables are given the transformation factors of the fluxes from a specific X-ray energy band to the 0.5-7 band, assuming Gamma 1.7 with Nh 6e20 and 0. Table 1 >>> Gamma Nh   MinE MaxE ModeledFx  Fx_in_0.5-7_band 1.7   6.0E20 2.0  25.0 7.4353E-9  1.524470492137473 1.7   6.0E20 0.1  2.0  2.177E-9   0.44635349756468984 1.7   6.0E20 3.0  10.0 3.234E-9   […]

That’s an impressive image of how to clean the main, 3.54m diameter, mirror of the New Technology Telescope (NTT) on La Silla. “This very delicate process is performed using a natural sponge, soft soap and distilled water”, as stated at ESO’s site.  

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