NGC 6822 in Sagittarius, Barnard's Galaxy

NGC 6822 is a barred irregular galaxy

in the constellation Sagittarius.

Hover over the picture for an annotated version

Date:  23 July 2025 and 13 August 2026

FOV:  cropped to 45' × 30'

Rotation:  −89.998°

Telescopes:  Celestron C14 SCT (3910mm, f/11)

Starizona HyperStar (731.83mm, f/1.9)

Celestron 9.25" EdgeHD SCT (nominally 2350mm, f/10

with Celestron 0.7x reducer, 1680.67mm, f/7) and an

Guiding:  ZWO ASI120MM mini mono guide cameras,

SVBony SV165 Mini 40mm f/4 guide scopes

Computers:  ASIair pro and ASIair plus

Mounts:  iOptron CEM 120 and ZWO AM5N

Cameras:  ZWO ASI2600MC Duo (-10°C) at 0 gain and

ZWO ASI6200MC Pro APS/c (-10°C) at 100 gain

Pixel size:  3.76 μm

Resolution:  2.594 arcsec/pixel and 0.462 arcsec/pixel

Frames:  65 × 300 seconds C14", Optolong UV/IR cut filter,

29 × 300 seconds MK127, Optolong L-eNhance filter

Total Time:  7 hours and 50 minutes

Calibration:  20 flats, 20 dark flats, and 20 darks per session

Processing:  Pixinsight

preprocessing → UV/IR×65 and L-eNhance×29

LeNh:  MGC, DBE, SPCC, BXT, NXT, StarXT → LinearLeNh

UV/IR:  MGC, DBE, SPCC, BXT, NXT → LinearUVIR

LinearUVIR:  StarXT → LinearUVIR_StarXT

LinearUVIR:  MultiAdaptiveStretch → Stars

PixelMath ~(~LinearLeNh*~LinearUVIR_StarXT) →

LinearStarless, HTS, GHS, MStr, MAS,

PixelMath 0.25*(HTS + GHS + MStr + MAS) → Starless

PixelMath ~(~Stars*~Starless), DynCrop/Scale

Location:  Darling Hill Observatory near Vesper, NY