M 10

Click on the image to display it full screen
Date
2015/05/20

Observation place
My permanent observatory in Longueuil
in white light pollution zone

Technical

TelescopeCelestron Edge HD - Diameter 203mm (8``), focal length 2032mm, f / 10
Focal reducerf / 6.3 (63%)
MountCelestron CGEM
Imaging cameraAtik 383 L + monochrome regulated at -20o Celsius
Autoguiding cameraZWO ASI 120MM in parallel with the Orion mini guide
Image typeL (RGB)
ExhibitionLuminance (25 x 1 'bin 2 × 2), R (16 x 2' bin 2 × 2), V (10 x 2 'bin 2 × 2) and B (20 x 2' bin 2 × 2)
Image acquisition softwareMaxim DL
Guidance softwarePHD Guiding 2
PretreatmentMaxim DL
TreatmentPhotoshop and PixInsight

Object description

Object typeGlobular cluster 
ConstellationSerpentary
Visual magnitude6,6
Distance14300 light years
Diameter80 light years
Dimension seen from Earth15,1 arc minutes  
The globular cluster M10 is one of the closest to the solar system since it is located only 14300 light years away. Despite a modest diameter of only 60 light-years, its apparent diameter is therefore quite large and is equivalent to half that of the full moon. The cluster is very poor in variable stars, it contains only 3. The brightest stars of the cluster have an apparent magnitude of 13.  

In a sky with little light pollution and thanks to its magnitude of 6,6, the cluster is easily visible with binoculars in the form of a milky spot. It keeps the same look in a 60mm bezel. From a 150 mm diameter instrument, the cluster begins to resolve into stars and then has a grainy appearance. A 200 mm telescope allows you to have a good view.  

The image presented was taken from my observation site located in Longueuil, in an environment of significant light pollution. I still managed to resolve the cluster well with a beautiful natural saturation of the colors of the stars, which is surprising in my light pollution site.  

This image was acquired with my new Atik 383 L + monochrome CCD camera. I used color filters (red, green and blue) to produce the image in color. I did not use an emission filter. Indeed, for some time, I doubt the effectiveness of these filters for star clusters and galaxies. To combat light pollution, I took a lot of individual short exposure images, which increased the signal from the cluster and reduced the background noise caused by light pollution, a technique that effectively replaces light pollution. 'use of an antipollution filter.
Richard Beauregard
Sky Astro - CCD
My impression "We cannot be alone in this gigantic universe"