Explanation : Region of the Lambda Orionis is a complex of molecular clouds and H II regions visible in the direction of the northern part of the constellation Orion , a part of the outer regions of the large molecular complex nebulous of Orion, one of the star-forming regions most studied and best known at all, as well as the galactic region closer to the solar system in which it takes place the formation of massive stars . It takes its name from its main star , λ Orionis , a blue giant responsible for the ionization of gas nebulae circostanti.La region is a good study model for understanding the evolution of giant molecular clouds , from the formation of massive stars up to ‘ exhaustion of the phenomena of star formation within them, with the dispersion of the residual gas and the dissolution of the OB associations formed in it.The distance of the region was determined for the first time in the course of the seventies , through the study of the stars of the main sequence , the value obtained was 440 ± 40 parsecs , equivalent to about 1430 ( light years).This value was questioned when the satellite Hipparcos measured the parallax of thirteen of the stars belonging to the association and the measurements in these cases did not receive an accuracy rate of less than 25% and the distance turned out to approximately 380 ± 30 parsecs , rather than reduced with previous estimates . The most widely accepted value for the association is the one obtained through the study of photometry , which provided a value of 450 ± 50 parsecs.This , like the previous measurements , makes the distance of the Region of Lambda Orionis compatible with that of other regions of the nebula of Orion complex , such as the Orion Nebula , whose distance is estimated to be about 443 parsecs, the region of Orion B , located 475 parsecs, and other regions of minors, the maximum distance is of about 500 parsecs. Credit: Wikipedia
OTA: Boren Simon Newton 200 f2.8
Tot. Exp: L 21,2 hours, unb. (H-alpha flt.)
RGB: R 84 min; G (R/B); B: 2,0 hours.
CCD : SBIG ST8300 (unb cooled -15° C)