Messier 3.

Note
My first "real" LRGB image. Total exposure rather short.
Strong light pollution from the moon was present and the wind disturbed the guiding so there were some issues to deal
with.


About
Messier 3 (also known as M3 or NGC 5272) is a globular cluster in the constellation Canes Venatici. It was discovered by Charles Messier in 1764, and resolved into stars by William Herschel around 1784. This cluster is one of the largest and brightest, and is made up of around 500,000 stars. It is located at a distance of about 33,900 light-years away from Earth. M3 has an apparent magnitude of 6.2, making it a difficult naked eye target even with dark conditions. With a moderate-sized telescope, the cluster is fully defined. It is estimated to be 8 billion years old. It is pretty difficult to spot this object in an amateur telescope without GoTo as it has no nearby pointer stars.
Processing
CCD Stack and CS5

Exposure
Ha: 10x5 min, RGB: 18x3 min

Calibration
Darks, bias and flats.

Filters
Baader LRGB.

Cooling temp
-20´ C

Mean FWHM
3.88"

Date
March 23rd 2011

Location
Krigslida, Stockholm, Sweden.
N59 06 52.4    E 18 03 54.5

Image aqusition
MaximDL Pro

Scope control
Sky X Pro Native drv, and Maxim DL with Astro-Physics V2 drv.

Telescope
TEC APO 140

Mount
Astro-Physics Mach 1 GTO

Camera
QSI 583 WSG

Guiding
OAG guiding with Lodestar Guider

Focus system
Starlight Micro Touch and Focus MAX.


Inverted B/W image