Archive for 2020

Creating OSIRIS mosaic images

Posted September 15, 2020 By grigoris

To properly process data (either imaging or multi-slit spectra) from the OSIRIS instrument at GTC you need first to convert the original data to single images. The raw fits data contain two extensions corresponding to the two CCD sensors. To combine these into a single 2110 X 2051 pixels image (including the gap between the […]

Preparing for MOS observations with the GTC

Posted August 18, 2020 By grigoris

The pandemic of Covid-19 has obviously affected our observing runs also. ESO is (still) totally shut down while GTC after some off period it seems that it is under some limited operation. Our accepted observing program with GTC includes Mulit-Object Spectroscopic observations with the OSIRIS instrument. For this we need to prepare masks, i.e. metal […]

Some 2020 Perseids observed …

Posted August 17, 2020 By grigoris

It has been many many years since my last visual observations of meteors (back in 2010…). Last week I found the opportunity to observe a bit the peak of the Perseid shower. I observed for a couple of hours, just before the moon rise, from my place in the relatively light polluted Heraklion of Crete. […]

eROSITA’s first all-sky image

Posted June 26, 2020 By grigoris

Recently the first all-sky image of the X-ray sky was released by the eROSITA instrument on-board the Spectrum-Roentgen-Gamma” (SRG) mission. It is fascinating that they refer to a million X-ray, which is almost 10 times more than what has been discovered from all X-ray surveys so far, so a bright X-ray future lies ahead! The […]

Evolved Massive Stars at Low-metallicity II. Red Supergiant Stars in the Small Magellanic Cloud Ming Yang, Alceste Z. Bonanos, Bi-Wei Jiang, Jian Gao, Panagiotis Gavras, Grigoris Maravelias, Shu Wang, Xiao-Dian Chen, Frank Tramper, Yi Ren, Zoi T. Spetsieri, Meng-Yao Xue We present the most comprehensive RSG sample for the SMC up to now, including 1,239 […]

Packaging Skinakas’ primary mirror

Posted March 9, 2020 By grigoris

Back in November of 2019, the primary mirror (of 1.3m) at the Skinakas Observatory was dismounted to send it for recoating (a procedure performed once every 4-5 years). The following short clip shows the packaging of the mirror, a very delicate procedure (the whole process took several hours … compressed to a few minutes).

The second nearest exoplanet – Proxima c

Posted January 20, 2020 By grigoris

It is exciting to see that the nearest star to our Sun has more than one planet (Proxima b, [1]). In a paper led by Mario Damasso and Fabio Del Sordo [2] revealed the existence of another one. The Proxima c is a planet with an orbital period of about 1900 days (~5.21 years), a […]