15,700 ly

The forecast was a bit iffy (wind and high cloud) but I decided to get my gear out anyway and I’m glad I did as the weather turned out OK. My last attempt on M12 was 4 years ago, and this is a far better image. Wikipedia indicates this globular is more loosely-packed than usual, and has fewer low-mass stars than usual; it is reported to be about 75 ly in diameter. I like the colors it displays, but as usual I’m never too certain that my representation of the colors is accurate, and these are definitely not the same as I got last time with a one-shot-color camera. The star field in this part of the sky is quite dense and rich.

Date: 19 May 2020
Subject: M12
Scope: AT8IN+High Point Scientific Coma Corrector
Filters: ZWO 31 mm diameter unmounted L, R, G, B
Mount: EQ-6 (EQMOD 2.000j)+PEC
Guiding: Orion Thin Off-axis Guider + ASI120MM-mini +PHD 2.6.8 (Win 10 ASCOM)
Camera: ASI1600MM-Cool, -20 °C, Gain 139 Offset 21
Acquisition: Sequence Generator Pro 3.1.0.479
Exposure: 24x180 L, 15x180 R, 15x180 G, 15x180 B
Stacking: Deep Sky Stacker 4.2.3 (64-bit) dark+flat+bias, κ-σ stacking with κ = 1.5
Processing: StarTools 1.6.394RC: Composed L, R, G, & B accounting for total integration times in creating a combined synthetic luminance. Cropped, wiped (vignette), developed (95%), HDR (reveal core), deconvoluted slightly (2 pixels), and untrack denoised. In Photoshop, some levels adjustments to darken the background followed by 1 round of Astronomy Tools’ “less crunchy more fuzzy”. AstroFrame.