Deep Sky Object in Winter
Sh2-291 (Diffused Nebula in Monoceros)


Date & Time: Dec 27 2025, from 24:33 to 25:28 JST(+0900)
Composed 10 shots with 6 minutes exposed
Optical: Meade 25cm(10") Schmidt-Cassegrain with conversion lens (f=1600mm, F6.3)
with IDAS LPS-P1 Light-pollution suppression filter
Auto-guided with Meade LX200 Equatorial & Lacerta M-GEN
Digital Camera: Nikon D810A
Location: Ooizumi, Hokuto city, Yamanashi pref.

Camera Settings: Recording Format...14bit CCD-RAW, converted to 16bit TIFF(4080×4080)
Device Size...20×20mm
Sensitivity...ISO4000, White Balance...Daylight


Sh2-291 / Diffused Nebula, type 5 E
R.A.06h 55m 21.9s (2000.0)
Dec.-08°00' 25" (2000.0)
Apparent Size9.4'
Real Size75 light yrs.
Magnitude -
Distance27700 light yrs.
Sh2-291 is a faint diffuse nebula located about 1.8°: west of the open cluster M50 in the southern part of Monoceros. It has a roughly circular shape with a diameter of just under 10 arcminutes, and its distance is estimated to be about 27,000 light-years. Because it has low surface brightness, the nebula appears faint, but dark nebulae seem to form an intricate, interwoven structure within it.

→Wide-field around Sh2-291



Around M50, Sh2-291
Sh2-299, Sh2-300

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