Lower’s Nebula (Sh2-261): A Subtle Emission Nebula in Orion

Lower’s Nebula, also cataloged as Sh2-261, is a faint emission nebula located in the constellation Orion, embedded within a region rich in ionized gas and interstellar dust.

The nebula is named “Lower’s Nebula” after astrophotographer Dennis Lower, whose detailed images helped bring attention to this otherwise subtle object. Scientifically, it was cataloged in 1959 by Stewart Sharpless as part of his survey of H II regions across the Milky Way.

Captured in narrowband hydrogen-alpha (Hα), sulfur-II (SII), and oxygen-III (OIII), this image reveals the nebula’s softly layered structure. The warm hydrogen emission outlines dense clouds of ionized gas, while oxygen and sulfur trace regions shaped by energetic radiation from nearby young stars. Together, these elements illustrate a quiet but ongoing interaction between stellar radiation and the surrounding interstellar medium.

Unlike brighter and more dramatic nebulae, Lower’s Nebula is defined by its delicate glow and smooth gradients, offering a glimpse into a calmer phase of stellar feedback within Orion’s vast star-forming environment.

Telescope: Sky-Watcher Evostar 72ED APO Refractor
Mount: iOptron HAE43
Camera: ZWO ASI183MM Pro (cooled, monochrome)

Filters:
Hydrogen-alpha (Hα)
Sulfur-II (SII)
Oxygen-III (OIII)

Guiding: Svbony Mini Guide Scope 30mm
ZWO ASI120MM guide camera

Capture Software: ASIAir Plus

Processing Software: PixInsight, Photoshop

📊 Exposure Details
Hα: 30 × 180s (1h 30m)
SII: 30 × 180s (1h 30m)
OIII: 30 × 180s (1h 30m)
Total Integration: 4h 30m