NGC6121 or M4 in Scorpius

NGC6121, M4, is a globular cluster in Scorpius.

Visually, M4 is noted for the bar of stars across its core and

a stirrup or arc of stars (above the bar in this picture).

Large telescopes and pictures of M4 are so bright

that these feautres are difficult to see.

Hover over the picture for an annotated version

Date:  10 April 2022 and 24 June 2022

FOV:  approximately 68' × 45'; M4 is approximately 23'

Telescope:  Stellarvue SVX102T + SFFX-1 flattener (714mm, f/7)

Guiding:  ZWO ASI120MM mini mono guide camera,

Stellarvue F050G 50mm guide scope

Computer:  ASIair pro Raspberry Pi

Mount:  iOptron CEM40

Camera:  ZWO ASI071MC Pro Cooled (-10°C) Color CMOS with gain 240

Filter:  Baader Light Pollution Moonglow filter with IR cut

Stacking:  Thirty-nine 240 second frames using Deep Sky Stacker

Total Time:  2 hours 36 minutes

Processing:  Pixinsight – SPCC, DBE, BlurXT, NoiseXT, Mask, GHS, HST,

PMath add Mask + GHS + HST, HDR6, Sat, DynCrop, Scale

Location:  Cherry Springs State Park near Coudersport, PA (10 April 2022)

Darling Hill Observatory near Vesper, NY (24 June 2022)