M3 – Globular Cluster Canes Venatici

Telescope: Meade 12” LX850 ACF @ f/8, Orion Atlas EQ-G

Camera: Baader modified Nikon 610; Gain: 200

Filter: High Point 2” IR Blocking Filter

Guide scope: Astro-Tech 60mm, ASI290MM Mini, PHD2

Exposure: 39x60sec, saved as FITS

Darks: 32x60s, saved as FITS

Flats: 32×1/2sec, Tee shirt flats taken at dusk

Average Light Pollution: Red zone, Bortle 8, poor transparency, haze

Lensed Sky Quality Meter: 17.8 mag/arc-sec^2

Stacking: Mean with a 2-sigma clip.

White Balance: Nebulosity Automatic

Software: Backyard Nikon, Deep Sky Stacker, Photoshop

M3 is a beautiful example of a globular cluster in a relatively lonely stretch of sky. The cluster is a member of the galactic halo and spends much of its time orbiting well outside the plane of the galaxy. It is presently 33,000 light years away from us, 40,000 light years from the galactic core, and 33,000 light years ‘above’ the galactic plane. Home to about 500,000 stars, M3 is relatively young as globular clusters go with an estimated age of 8 billion years.

M3 rises in the northeast during the early evening and is high overhead by midnight.