Hi Orestis,
Nice work mate -- good sketch. Alexander, as PGC said, I think Orestis was talking about the Eight-Burst Nebule on the Vela/Antlia border.
Castor is an interesting star. Double in small 'scopes, triple in larger ones and in reality a sextuple system (as revealed by spectroscopy) and part of the "Castor moving group".
http://stars.astro.illinois.edu/sow/castor.html
Best,
Les D