NGC 6820 and NGC 6823 in Vulpecula

NGC 6820 is an emission nebula in the constellation

Vulpecula.  Buried in NGC 6820 is an open

cluster, NGC 6823, about 6 kly away.

Hover over the picture for an annotated version

Date:  14 and 11 August 2026

FOV:  cropped to 75' × 50'

Rotation:  89.994°

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

Guiding:  ZWO ASI120MM mini mono guide camera,

SVBony SV165 Mini 40mm f/4 guide scope

Computer:  ASIair plus 256GB

Mount:  ZWO AM5N

Camera:  ZWO ASI2600 MC Duo Cooled (0°C) Color CMOS gain 100

Pixel size:  3.76 μm

Resolution:  1.053 arcsec/pixel

Filter:  Optolong UV/IR cut on 11 August

Optolong L-eNhance on 14 August

Frames:  56 × 300 second subs on 11 August

59 × 300 second subs on 14 August

Total Time:  9 hours and 35 minutes

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

Processing:  Pixinsight

preprocessing → UV/IR×56 and L-eNhance×59

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

MultiscaleAdaptiveStretch → Stars

Linear, StarXT, MStr, GHS, HTS, MAS, →

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

PixelMath ~(~Stars*~Starless) → Blend, scale

Location:  Darling Hill Observatory near Vesper, NY