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(IAAC) OBJECT: NGC5139 (Omega Cent., Globular)INST: 6" f/5 reflector



Observer:  Todd Gross
Your skill:  Intermediate - Many years
Date and UT of observation: 12/28/99
Location & latitude: Grand Cayman, BWI, 20n
Site classification: Suburban
Limiting magnitude(visual):approx.4.5zenith, 4 nr.object
Seeing (1 to 10 - worst-best): 5
Moon up (phase?): Yes, gibbous
Weather: Clear
Instrument: 6" f/5
Magnifications:34,54,76,88,109,138x
Filters used: none 
Object: NGC5139
Constellation: Cen
Object data: GC
Size(s): 37
Position: 13:27 -47:29
Magnitude: 3.7
Personal "rating" for this aperture: B+
Previously viewed Omega centauri through smaller aperture (80, 85mm 
barely resolved on previous trip) and larger aperture (10" SCT, wow) 
This is an important break-point aperture in these suburban sky conditions. 
Using 109 and 138x, I was able to completely resolve it when it got high 
enough in the sky, but it's uniform and huge starfield 
was still dim. It sprawled over a good chunk of the field of view, unlike 
M3 which I also viewed in the same session - which is tiny and unresolved 
at the same magnifications. 
Huge, round, uniform. I could know I was about to resolve it through 
it's center into individuals when working on seeing the brighter 
outlying members .. concentrating on the N/W side
of the cluster which had borderline 12th magnitude stars. Once able to see 
those,  much of the cluster broke down and swarmed the field.. 
Best resolved in a 5.5mm eyepiece, but more pleasurably bright and framed 
in the 7mm nagler. 
Only "ground sugar" resolution from 9mm on up through 22mm, but still a
pretty 
object due to it's overwhelming presence and increase overall brightness as
one
increases the exit pupil size.
Todd Gross
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