Instrument

12.5" RCOS @ ~ f/9 (2880 mm fl) at 0.64 arcsec/pixel. Shown at 0.85 and 1.77 arcsec/pixel.

Mount

Paramount ME

Camera

SBIG STL-11000 w/ FW8 filter wheel & AstroDon Gen-2 LRGB filters.

Acquisition Data

11/8/2016 to 11/14/2016 Chino Valley, AZ.  with CCD Commander & CCDSoft.  AOL guided

Exposure

eXcalibrator RGB ratios are 1.00, 0.99 & 1.16

Software & Processing Notes

• CCDSoft, CCDStack, PixInsight, Photoshop CS6.

• eXcalibrator v5.0 for (g:r) color balancing, using 108 stars from the SDSS-DR9 database.

• CCDBand-Aid to repair KAI-11000M vertical bars.

• CCDStack to calibrate, data reject and combine the sub exposures, create the RGB image and apply a mild  Positive Constraint deconvolution.

• PixInsight for gradient removal, non-linear stretching with HistogramTransformation.

• PhotoShop for the final touch-up.

Comment

The cluster is shown rotated 120° counter-clockwise.

M2 is a globular cluster in the constellation of Aquarius. Its actual position in the galactic halo places it in the southern galactic cap, almost directly beneath the southern pole of our Galaxy, the Milky Way, and at a distance from us of around 47,000 light-years.

M2 is a compact and fairly dense globular cluster. It is one of the richer globulars, containing more than 100,000 stars and stretching more than 150 light-years across. Like other globular clusters, M2 is made up of stars that are all the same age. These are amongst the oldest stars in our Galaxy, at an age of about 13 billion years.

Source: NOAO/AURA/NSF.