juin 2010

These days Bess observers were asked for Ha spectra coverage of HD171219 in Ophiucus by COROT  team. COROT is a very accurate photometric space telescope. Its primary goal is asteroseismology, star variability and secondary is eclisping exolplanet (16 to date discover) http://corot.oamp.fr/. For a couple of weeks, COROT will measure the tiny star luminosity variation. HD171219 is Be star, view by the equator, shell star, of mV 7.65 ... [Lire la suite]

This new highly variable Be star seems to be very strange. Each six differents spectrums taken between April 25th and June 6th are different ! So fast and intense variation from a Be star are not common. Sheliak is an example, perhaps unique with FF cam.  "6 spectres differents du 25 avril au 6 juin ! Les variations sont rapides et intenses, en profil et en largeur équivalente. Rien de commun avec la majorité des Be. Elle partage cette activité avec Sheliak, un système complexe aux variations similaires."  A period, if... [Lire la suite]

The LhiresIII spectrograph has a built-in neon lamp for calibrating stellar spectrum. Taking one neon spectra before and after stellar exposition is highly recommended in high resolution spectrography cause of the mechanical instability of this "at telescope focus" slit spectrograph. Here is an illustration of the mechanical effect on the shift of the band pass of the neon spectrum.   " Dérive de la bande passante du LhiresIII sur un spectre du néon avec en haut une rotation de 180° en Dec, en bas une rotation de 90° en Ra... [Lire la suite]

Spectroscopy of eps aur in these times is a tought task. I've been able to follow esp aur during end of may and this early June with a higher pier. I've started capture during daylight, with manual autoguiding, having still 40mm before epsaur set behing neirborough houses. My observatory is on the eastern slope of an urban hill and the only possibility for me to do spectra of epsaur is to begin capture during daylight. The difficulty is to spot it. I used a goto mount but it's not a perfect method as i used the moon or the sun... [Lire la suite]