M5: Globular cluster in Serpens...

[Hallingskies]

• Date: 4th & 5th May 2018
• Equipment: SXV-H9, Vixen 114mm f5.3 ED refractor, NEQ6 mount, guiding with Lodestar X2/PHD  
• Subframes: 50 x 30s, 30 x 100s and 20 x 300s luminance, 25 x 100s each for RGB (2 x 2 binned), 20 flats for each channel.

M5 often seems to be overlooked in favour of its flashier cousin, the "Great Globular Cluster" M13 in nearby Hercules, yet it is only half a magnitude fainter and in many ways is a more rewarding object to view through a telescope.  In my 8-inch Vixen VC200L , M5 shows up as a cluster of pin sharp stars, gradually brightening, yet still resolvable, right the way to its bright core.  M13, although bigger and brighter, doesn't offer as "granular" an appearance, at least not to me.

Luminance stacks of three different exposure lengths were layered and blended in PaintShop, in an effort to give a final luminance frame showing an apparent resolved core of stars.  This was combined with an RGB stack in AstroArt to give the final image.

Skies were very clear for the two nights needed to acquire the frames I wanted, but the seeing seemed a little variable, giving rise to a PHD guiding graph that often resembled an ECG trace.  Still, PHD worked its magic and the stars still came out OK-ish, with only a trace of distortion towards the outermost corners of the final image.  Clear skies also helped keep the background noise down, without having to resort to clipping or smoothing.

And it was so nice be able to sit out at night in the observatory at a balmy 10 degrees...

[des anderson]

That`s one great image, well done. Des

[MarsG76]

What a great image.... thanks for posting.

[celestron8g8]

GCs' are my favorite . Great capture !