about Grigoris Maravelias
Month: <span>January 2012</span>

Month: January 2012

AAVSO top visual observers

I just stumbled upon an interesting article about Rod Stubbings, a visual observer who made more than 200,000th variable star observations! This, as Mike Simonsen says, places him in top five visual observers in the history of variable star astronomy. An interesting image of the persons and their corresponding number …

PSF or DIA data from OGLE II?

OGLE (Optical Gravitational Lensing Experiment) has a large database of photometry data available to the public. OGLE II data (second phase) are available with option to select the photometry method used, ie. PSF and DIA photometry. PSF, a modified DOPHOT photometry process, was used during the first phase of OGLE, …

VStar conflicts with java used

VStar is a multi-platform variable star visualisation and analysis tool, developed under the CitizenSky project and the AAVSO. Its use is straightforward if java is installed. But you should be carefull what java you are using… I tried to use VStar in two different machines running Ubuntu 10.10 64bit and …

Watec’s illumination issue

During one observing night in December 2011, I noticed a strange “illumination” in the field, as the image from MetRec shows.   What is obvious from the above image is that there is too much light coming from the bottom, which affects the regions of interest, the flat-field image and …