Omega Centauri Globular Cluster in Centaurus
with 6" f/3.6 Meade Cometracker Astrograph 
Uploaded 5/29/17

This turned out to be quite a project. The pine trees in Payson near out house have grown so much in the past several decades that we can no longer see this cluster from ground level in the back yard observatory. To remedy this and get a new shot of this stunning object, I set up our new Bresser mount on the balcony, which is 14 feet above the ground on the back of the house. The mount tracks superbly and a series of 1 minute unguided exposures were taken. Seven of them out of 30 did not have tree limbs, wood stove vent stacks or other obstructions - but ALL of them had perfectly round stars. Here I stacked 7 of the unobscured shots to produce this portrait.

Color balance at this low elevation is a huge problem, but easy to fix. The cluster came out deep brown/orange from the low altitude haze. To correct the lack of blues and greens at this elevation, I first split the RGB data out as separate channels. Then in Maxim DL, remixed them at different mix ratios other than the 1:1:1 that is the current condition. By setting the mix ratios to 1:1.3:2 the blues and greens were completely restored, and the proper globular colors became visible.

The six inch with the coma corrector produces sharp stars across the field, and no other sharpening or deconvolution is normally required. A nice history on this instrument - which is quite a collectors item now - can be found on our web site here.

Half a dozen galaxies appear in this field, however only the brightest few are seen on the full sized image. Select an image size for a larger view: 1600 x 1200
Instrument: 6" f/3.6 Cometracker Schmidt Newtonian with Baader MPCC Mount: Bresser LDX-75 Camera: Canon XTi DSLR modified by Hutech for full spectrum Guider: None Exposure: 7 mins total Location: Payson, Arizona, Elevation: 5150 ft. Sky: Seeing FWHM = 2 arcsec , Transparency 7/10 Outside Temperature: 55 F Image Processing Tools: Maxim DL6: Calibration, aligning, stacking PixInsight: Curves, Deconvolution Photoshop CS2: Curves, Color Correction, Gradient removal (Grad Xterminator), Cleanup HOME GALAXIES EMISSION NEBS REFLECTION NEBS COMETS GLOBULARS OPEN CLUST PLANETARIES LINKS