November 11, 2024

M3 – Globular Cluster Canes Venatici

M3 – Globular Cluster Canes Venatici

Telescope: Unitron 155 4” f/15 refractor, Atlas EQ-G

Camera: Canon EOS Ra full frame DSLR

Filter: 2” GSO IR Cut Filter

Guide scope: Orion 50mm Guidescope, ASI120MM, PHD, Dithered every 4 subs

Exposure: 26x120sec, ISO 800, saved as RAW

Darks: Internal (Long Exposure Noise Reduction)

Flats: 32×1/80s tee shirt flats taken at dusk

Average Light Pollution: Bortle 8, poor transparency, haze

Lensed Sky Quality Meter: 18.3 mag/arc-sec^2

Stacking: Mean with a 1-sigma clip

White Balance: Nebulosity Automatic

Software: Backyard EOS, Deepsky Stacker, Nebulosity, Photoshop

This is the first test image taken with my Unitron 155 on my Atlas EQ-G. One thing that impressed me about the 155 was the exceptionally flat field and nearly perfect star shapes across the entire field even with a full-frame camera. The shows a lot of potential for deepsky imaging as well as other tasks such as photometry and astrometry.

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 is currently well placed rising in the northeast during the early evening.