The observation of Angegh–Vulture (Cygnus) constellation in Armenia 32 000 years ago

Scheduling a constellation of agile earth observation satellites with preemption

In this paper, we consider a scheduling problem for a set of agile Earth observation satellites for scanning  different parts of the Earth’s surface. We assume that preemption is allowed to prevent repetitive images and develop four different preemption policies. Scheduling is done for the imaging time window and transmission time domain to the Earth stations as well. The value of each picture ...

SPI / INTEGRAL observation of the Cygnus region

We present the analysis of the first observations of the Cygnus region by the SPI spectrometer onboard the Integral Gamma Ray Observatory, encompassing ∼ 600 ks of data. Three sources namely Cyg X-1, Cyg X-3 and EXO 2030+375 were clearly detected. Our data illustrate the temporal variability of Cyg X-1 in the energy range from 20 keV to 300 keV. The spectral analysis shows a remarkable stabilit...

40 Years Ago

always voice his unhappy or distressing thoughts, and it is often most difficult to recognise the way he is tending, or having recognised it to induce him to seek the help and advice that would save him. And even when his condition has been realised and the man himself persuaded to have treatment, the difficulties in the ^ay of obtaining it for him are often insuperable. Outside of London and a...

Twenty Five Years Ago

so rarely met witH that a description of the following case is not without interest. AEuropean, aged 38, was admitted on the 4th February, 1929, with paresis of the left arm and leg. His previous history showed that he contracted syphilis in 1915, for which he was treated with a full course of murcury and galvarsan. In 1919 his Wasserman reaction was still positive and he had a further course j...

Seventy Five Years Ago