Michael A. Stecker
mastecker@gmail.com


 


M3 photographed from Los Angeles, 4-2023
file: M13-60sX40-AM5ASI533Cel925f7-4152023a3a.jpg
Messier 3 (M3) in the constellation Canes Venatici has an estimated age of 11.4 billion years (nearly 3-times the age of earth).  It is one of the largest and brightest globular clusters of our Milky Way galaxy centered 32,600 light-years (10 kpc) away from Earth.  With about 274 variable stars it has by far the most found in any globular cluster.  M3 has a high metalicity -- abundance of elements other than hydrogen and helium.
 
Photographic data
Telescope:
Celestron EdgeHD 9.25-inch SCT at f/7  (FL=1,650 mm)
with SVBony 60 mm f/4 guidescope (FL=240 mm)
.
Mount:
ZWO AM5 harmonic mount
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Cameras:
Main imaging: ZWO ASI533MC-Pro cooled color camera
Guide camera: ZWO ASI662MC color planetary camera (2.97 micron pixels)
.
Exposure:
60 sec X 40 lights with calibration frames
.
Filter:
Optolong L-Pro