M2 – Globular Cluster in Aquarius

Telescope: Unitron 510 5” f/16 refractor, Atlas EQ-G

Camera: Canon EOS Ra full frame DSLR

Filter: 2” ZWO IR Cut Filter

Guide scope: Williams Optics 50mm Guidescope, ASI290MM, PHD

Exposure: 24x60sec, ISO 1600, saved as RAW

Darks: Internal (Long Exposure Noise Reduction)

Flats: 32×1/10s sky flats taken at dusk

Average Light Pollution: Bortle 8, fair transparency

Lensed Sky Quality Meter: 18.6 mag/arc-sec^2

Stacking: Mean with a 1-sigma clip

White Balance: Nebulosity Automatic

Software: Backyard EOS, Deepsky Stacker, Nebulosity, Photoshop

M2 is a big, beautiful globular cluster that is well placed in the eastern sky in late summer and early fall. It is an easy target for a small telescope. Under dark skies it can even be glimpsed without a telescope or even binoculars. M2 is about 37,500 light years away and lies beyond the galactic center. Like most globular clusters M2 is an ancient relic of the early universe with an estimated age of about 13 billion years.

This is the fourth of 5 test images taken with my Unitron 510. M2 is currently rising in the east in late evening. (Photo credit; John Graham, 7/14/2023)