NGC 6809, Messier 55 in Sagittarius

NGC 6809, M55, is

NGC 6809, M55, is one of the easiest globular clusters

to resolve.  Located in the constellation Sagittarius,

M55 contains 100 000 stars and

is 17.6 kly from us.

Hover over the picture for an annotated version

Date:  3 July 2022

FOV:  approximately 60' × 40'; the angular size of M55 is about 19'

Telescope:  Stellarvue SVX102T + SFFX-1 (737.5mm, 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

Pixel size:  4.78 μm

Resolution:  1.337 arcsec/pixel

Filter:  Baader Light Pollution Moonglow filter with IR cut

Stacking:  Twenty-one 240 second frames using Deep Sky Stacker

Total Time:  1 hour and 24 minutes

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

PMath GHS + Mask + HST, Sat, Bkg, DynCrop/Scale

Location:  Cherry Springs State Park near Coudersport, PA