NGC 6781, the Snowglobe Nebula in Aquila

NGC 6781 is a small planaetary nebula in the constellation

Aquila.  Located about 1500 ly from us, it appears

very near the celestial equator.  The dense stars in

the Milky Way are responsible for its name.

The south up view makes it look like the

Snowglobe nebula is resting on a stand.

Hover over the picture for an annotated version

Date:  19 July 2026

FOV:  approximately 10' × 6' 40"; the angular size of NGC 6781 is about 1.9'

Rotation:  179.989°

Telescopes:  Orion Apex Mak-Cass (1382mm, nominally 1540mm, f/12.1)

and Celestron 9.25" EdgeHD 925 SCT (1678.39mm, nominally 1645mm, f/7

with Celestron's 0.7 x reducer)

Guiding:  ZWO ASI120MM mini mono guide cameras,

SVBony SV165 Mini 40mm f/4 guide scopes

Computer:  ASIair pro Raspberry Pi

Mount:  iOptron CEM40 2022, ZWO AM5 2025

Camera:  ZWO ASI071MC Pro Cooled (-10°C) Color CMOS with gain 90 (Mak-Cass)

and a ZWO ASI6200MC Pro Cooled (-10°C) Color CMOS with gain 100 (C-9.25")

Pixel size:  4.78 μm (Mak-Cass, 3.76 μm, (C-9.25")

Resolution:  0.713 arcsec/pixel (Mak-Cass), 0.462 arcsec/pixel (C-9.25")

Frames:19 July 26,44 × 300 seconds ×90 gain, Mak-Cass,

19 July 26,68 × 300 seconds × 100 gain, C-9.25" EdgeHD

Filter:  none for the Mak-Cass, Optolong L-eNhance for the C-9.25"

Stacking:  one hundred and twelve 300 second frames using Pixinsight

Calibration frames: 20 dark, 20 flat, 20 dark flat per session

Total Time:  9 hours and 20 minutes

Processing:  Pixinsight

preprocessing → NoFilter×44 and L-eNhance×68

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

MAS, CurvesTransformation → Starless

NoFilter:  MGC, SPCC, DBE, BXT, NXT → LinearStars

MultiscaleAdaptiveStretch, Sat → Stars

PixelMath ScreenBlend(Stars, Starless), DynCrop/Scale

Location:  Darling Hill Observatory near Vesper, NY