Lorenzo Comolli's Astronomy HomePage

Click on the image for a higher res version - MOUSE OVER for a comparison with a simpler but identical processing

We, observers of the Northern hemisphere, cannot even imagine a globular cluster better than M13 in Hercules. But we're missing that in the deep South some gems are hidden, such a the master of all clusters: Omega Centauri. So bright that, the name reveals, it was mistaken for a star!
This is a not fair comparison because each image was processed independently to extract as much as possible. I've made also a comparison with a simpler but identical processing, and M13 is even more ugly: see mouse over.

For a comparison of the 6 best globular cluster of the whole sky, look at "The best globular clusters"; or for only Omega Cen look at "Omega Centauri globular cluster".

Technical Data
Optics	Takahashi FS152 apo refractor
Focal Lenght	1216 mm (direct focus, no flattener)
Focal Ratio	f/8
Exposure Time	For each image, respectively: 1h30min, 1h30min (single exp of 10 min)
CCD	Canon EOS 5D with Baader filter
Sensitivity	800 ISO
Location	Omega Cen: Tivoli Farm (Namibia) at 1350 m height; M13: Bogli (PC, Italian Apenines) at 1350 m
Date	Omega Cen: 28 August 2011; M13: 2010
Mount	Omega Cen: Fornax 51; M13: 10Micron GM2000
Tracking	SXV-H5 on a Vixen 80/640 apo refractor
Temperature and humidity	T= 15 °C, RH= 27 %
Sky brightness at zenith (with SQM-L)	21.6 mag/arcsec^2
Notes	This image is a collaborative effort of the Namibia 2011 expedition. Processing: Lorenzo Comolli. Images by: Lorenzo Comolli, Luigi Fontana, Giosuè Ghioldi, Emmanuele Sordini. M13 was imaged by Giosuè Ghioldi with the same telescope and camera from the Northern hemisphere.