Acrux, NGC 4609 and part of the Coalsack
Click for hires
Coalsack is one of the most famous dark nebulae of the Southern
Hemisphere. It lies near Alpha Crucis (Acrux), the main star of the Crux
constellation, a double star with nearly equal blue components
separated by 4". At 2° to toward East (here at right) a small open
cluster is present, NGC 4609.
||Pentax 75 apo refractor
||1 h 10 min
(single exp of 10 min)
EOS 5D with Baader filter
(Namibia) at 1350 m height
|31 August 2011
||Lodestar with a small refractor (F.L. 100 mm, aperture 23 mm)
||T= +14°C, RH=27%
|Sky brightness at
zenith (with SQM-L)
||21.6 mag/arcsec^2 (Moon low on the horizon)
image is a collaborative effort of the Namibia 2011 expedition.
Processing: Lorenzo Comolli. Images by: Lorenzo Comolli, Luigi Fontana,
Giosuè Ghioldi, Emmanuele Sordini.