"Yet another ball ?,  you decide - NGC 6229", 



"Yet another ball ?, you decide - NGC 6229"

Technical card

Imaging telescopes or lenses: Celestron EdgeHD 800

Imaging cameras: Atik 460 EX Mono

Mounts: Celestron Advanced VX

Focal reducers: TS Optics 2x ED Barlow

Software: PixInsight  ·  CCDciel

Filters: Baader Planetarium Luminance 1.25"

Dates:June 8, 2016June 9, 2016

Frames:Baader Planetarium Luminance 1.25": 176x5" (14' 40") -10C bin 4x4

Integration: 14' 40"

Flats: ~80

Bias: ~100

Avg. Moon age: 4.18 days

Avg. Moon phase: 18.70%

Basic astrometry details

Astrometry.net job: 1137848

Resolution: 437x385


NGC 6229 is a GC in Hercules. Because of a much closer M13 and M92 it isn't a popular target.
The GC was discovered by Herschel. Because of it's roundness Herschel classified it as a planetary nebula. Other observers have mistaken it for a comet.
Finally in 1856, Louis d'Arrest recognized it as a "very crowded cluster"

NGC 6229 is comparable to M5 in metallicity and age (~13Gy)
It contains a population of blue stragglers. Sanna et. al found 64 of them.
Astronomers have several explanations how blue stragglers stars (BSS) are forming.
My favorite BSS theory is a collision of two stars in a dense environmet of a GC.
This ball of stars "floats" in the outer halo of the Milky Way. 100.000 light years away from us...


This time I tried another setup for the image aquisition. I wanted to experiment a little bit.
The original FL of the SCT was extended to 4m with an 2x Barlow.
The CCD was set to a 4x4 binning. It results in a pixel resolution of 0.821 arcsec/pix. The FOV is something like 6.7' x 5.6'

The exposure time was set to 5 sec. I'm considering this setup as a kind of "lucky imaging".
In total, I acquired 2500 frames. With PI's SubFrameSelector , this number was reduced to 170 frames.
The annotated version shows the original, unprocessed image.



  • "Yet another ball ?,  you decide - NGC 6229", 


  • "Yet another ball ?,  you decide - NGC 6229", 


  • Final
    "Yet another ball ?,  you decide - NGC 6229", 




"Yet another ball ?,  you decide - NGC 6229",